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  • Title: Your Genes, Your Health
    Descriptive info: .. NEW! Your Genes, Your Health Blog!.. Bad Cholesterol.. When someone mentions cholesterol many will say, how is your HDL? Cholesterol travels through the blood attached to lipoproteins.. From a health prospective we try to maintain the good cholesterol (High density lipoproteins or HDL) and decrease the bad cholesterol (Low density lipoproteins or LDL).. The HDL aids the body in removal of bad cholesterol.. GO TO BLOG.. Explore.. Inside Cancer.. : A Multimedia Guide to Cancer Biology..  ...   within this web site is for educational purposes only, and should not be used as medical advice.. A physician should be consulted for any diagnosis and treatment options.. Visit the companion site!.. www.. dnaftb.. org.. 2002, Cold Spring Harbor Laboratory.. All rights reserved.. DNA Learning Center Home.. MORE DNALC SITES:.. DNA Interactive.. Eugenics Archive.. DNA from the Beginning.. Genes to Cognition Online.. CSHL Home.. About CSHL.. Research.. Education.. News & Features.. Campus & Public Events.. Careers.. Giving..

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  • Title:
    Descriptive info: Your feedback is highly appreciated and will help us to improve our ability to serve you and other users of our web sites.. For your convenience, we provide you the following two options:.. A questionnaire.. which will provide us with specific information needed to maintain the educational services and products we offer.. The average time for the completion of this survey is 2 min.. A comment form.. if you would prefer to send us a brief comment only.. Common Questions/Comments and Responses:.. Please add _____________ disorder to this site.. YGYH focuses on 15 disorders, which were  ...   Although we would like to help anyone looking for more information on other disorders, limits on funding and staff time shaped the site to the 15 disorders presented.. Can I download YGYH or is there a CD version of the site?.. YGYH is not available to download, nor is there a CD version.. We encourage you to link to the site for inclusion in classroom presentations.. Can I include a link to YGYH on my web page?.. We encourage links to YGYH that will bring information to people who want to learn more.. about genetic disorders..

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  • Title: Your Genes, Your Health
    Descriptive info: HOME.. Your Genes, Your Health.. is brought to you by:.. President.. Cold Spring Harbor Laboratory.. James D.. Watson.. Executive Editor.. David A.. Micklos.. Scientific Editor.. Jan Witkowski.. Writer/Managing Editor.. Shirley Chan.. Researchers/Writers.. Susan Conova.. Margaret Woodbury.. Design Director.. Susan M.. Lauter.. Media Designers.. Chun-hua Yang.. Wen-Bin Wu.. Eun-sook Jeong.. Computer Therapists.. Simon Ilyushchenko.. Adrian Arva.. Copy Editor.. Lynne Cannon-Menges.. Indispensible Interns.. Elizabeth Thomas.. Matthijs Muller.. Tony Chen.. Felix Hu.. Tracy Mak.. Regina Hu.. Ariel Gitlin.. Ray Zhang.. Copyright/Permissions.. Unless stated otherwise, all material appearing on this web site is:.. Copyright DNA Learning Center, Cold Spring Harbor Laboratory.. The images  ...   be consulted for any diagnosis and treatment options.. Material may be used in reports, research, and other noncommercial projects provided that proper attribution with the copyright notice accompany the material.. An acceptable copyright notice is as follows:.. Noncommercial, educational use only.. Material in.. may not be used in any form by organizations or commercial concerns, except with express permission.. All material appearing on this web site and not generated by the DNA Learning Center is accompanied by its own disclaimer and copyright notice.. Permission for reuse of such material must be obtained from the source.. Visit the companion site:.. http://www..

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  • Title: Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: Alzheimer Disease.. Duchenne/Becker Muscular Dystrophy.. Down Syndrome.. Fragile X Syndrome.. Marfan Syndrome.. Hemophilia.. Cystic Fibrosis.. Polycystic Kidney Disease.. Beta-Thalassemia.. Sickle Cell.. Huntington Disease.. Tay-Sachs.. Neurofibromatosis.. Phenylketonuria.. Hemochromatosis..

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  • Title: Alzheimer Disease - Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: To date, researchers do not know the precise cause of Alzheimer disease (AD).. They do not fully understand all the factors that start the disease process or what makes it progress.. However, scientists have been able to separate the disease into two distinct forms: sporadic Alzheimer disease and familial Alzheimer disease (FAD).. Both forms of AD are associated with the same structural, chemical, and clinical abnormalities exhibited with the disease.. The two structures in the brain that signal the presence of AD are amyloid plaques, found between neurons in the brain, and neurofibrillary tangles, found within neurons in the brain.. Both are clusters of proteins and can form as part of the usual process of aging.. However, in AD these proteins accumulate in greater quantities in two specific brain regions: the hippocampus and the cerebral cortex.. Amyloid plaques consist of beta-amyloid, a protein fragment of another larger protein called amyloid precursor protein (APP).. APP is found in most cell membranes in our bodies and is approximately 765 amino acids long.. The exact spot where the APP molecule is cut in nerve cells influences whether or not the beta-amyloid protein fragment is formed.. If it is first cut just outside the cell membrane, by an enzyme called alpha-secretase, the plaque-causing beta-amyloid fragment is not formed.. But if APP is first cut a bit farther away from the cell membrane by an enzyme called beta-secretase, the beta-amyloid fragment is formed.. The beta-amyloid fragment is either 40 or 42 amino acids long.. (The version most toxic to neurons seems to be A-beta 42.. ) Once formed, beta-amyloid is either degraded and cleared from the brain, or it remains in the brain, accumulating in clumps between neurons to become plaques.. The accumulation of these amyloid plaques seems to trigger the onset of AD, but researchers are still unsure if the plaques are the cause of the disease or simply a by-product of AD.. Neurofibrillary tangles, the other abnormal cluster of proteins associated with AD, occur within neurons.. These intracellular tangles consist of twisted threads of a protein called tau.. Normally the tau protein has a clear-cut function in the human nervous system it regulates the assembly of a neuron s internal structure and its nutrient transport system.. But in AD, the tau protein is chemically changed (extra phosphate groups are added to the protein) and this causes tau to become sticky.. When this happens, tau proteins pair up and twist around one another, forming a helical shape.. Clumps of this helical tau form the neurofibrillary tangles seen in AD.. Researchers are not sure exactly what triggers this change in the tau protein, but once it occurs the transport system of affected nerve cells collapses.. This leads to miscommunication between nerve cells and eventually cell death from lack of nutrition.. When enough neurons in an AD brain are damaged or destroyed, chemical imbalances begin to happen.. The most significant chemical change is a loss of the neurotransmitter acetylcholine, which serves to transmit messages from one neuron to another.. In AD, as damage to neurons in the brain increases, the ability to produce acetylcholine decreases.. This chemical loss means important messages are not transmitted in regions of the affected brain.. The end result of the structural (plaques and tangles) and chemical (decreased amount of neurotransmitter available to nerve cells) changes in the AD brain is progressive cell death and an overall shrinkage of brain tissue.. This culminates in the progressive clinical symptoms of AD such as mental decline, agitation, and delusions.. An absolute diagnosis of Alzheimer disease can only be made after the death of the patient.. At that time, an autopsy is performed and brain tissue is examined by a pathologist who looks for the plaques and tangles in the regions of the brain that are characteristic of AD.. However, trained doctors are able to correctly diagnose AD in living patients up to 90% of the time.. This is done in a two-step process: In the ruling-out phase ( possible AD), doctors look at several possible causes of a patient s mental symptoms.. Things such as drug reactions, brain tumors, strokes, thyroid problems, or chronic infections can all mimic the symptoms of AD.. When all other causes of a patient s symptoms are ruled out, a diagnosis of probable AD is made.. Currently there is no test that marks the presence of AD in the living patient, but brain images taken by magnetic resonance imaging (MRI) may show shrinkage of the hippocampus in AD patients.. Also, there is new evidence to suggest that MRI images of another area of the brain the entorhinal cortex may be able to predict who will develop mild cognitive impairment and then AD later in life.. The entorhinal cortex is a pre-processing center for memory formation and cups the hippocampus like a baseball mitt holds a ball.. In AD, shrinkage of this area occurs prior to changes in the hippocampus.. Another imaging technique used in the living brain is called positron emission tomography (PET).. Researches have found that people in the earliest stages of AD have decreased levels of sugar uptake in certain brain regions.. A PET test can show glucose uptake changes in the brain before symptoms appear, thus this and other tests in the pipeline may lead to earlier diagnosis of AD.. While no current treatment can stop the inexorable progression of AD, early  ...   has.. It may be useful to think of the Punnett square as a roulette wheel: Each child is a separate "spin of the wheel," so each child has a 50% chance of receiving the mutation.. In this family, one in four children has inherited FAD.. Other couples with the Alzheimer's mutation may have two, three, four, or even no children with FAD.. When people exhibit symptoms consistent with AD, doctors perform tests to exclude other causes of dementia or cognitive problems.. If no other reason is found, a tentative diagnosis is made a conclusive diagnosis of AD can only be made by direct examination of the patient s brain for characteristic plaques and tangles after death in an autopsy.. Alzheimer disease (AD) is characterized by progressive destruction and death of nerve cells in the brain.. This leads to shrinkage or atrophy in certain regions of the brain and a decrease in chemicals called neurotransmitters that ferry important messages between nerve cells.. The result of these cell and chemical losses is a steady decline in mental function.. Currently, there is no treatment that will stop or reverse the symptoms of Alzheimer disease.. However, the Food and Drug Administration has approved the use of three drugs that attempt to slow the progression of the disease.. These drugs work to maintain levels of critical message-sending chemicals in the brain called neurotransmitters.. The brains of people with Alzheimer disease (AD) exhibit two significantly different structures: amyloid plaques and neurofibrillary tangles.. Both the plaques and tangles consist mostly of protein and are thought to interfere with brain function and contribute to the dementia that is a hallmark of AD.. People with Alzheimer disease have two distinct sets of symptoms: cognitive and behavioral.. The severity of the symptoms increases over time.. Cognitive symptoms: Memory lossDisorientation ConfusionDifficulty with reasoned thought Behavioral symptoms: Agitation / Anxiety Delusions / Hallucinations Depression Insomnia Wandering Age is the major risk factor for Alzheimer disease (AD).. It is the most common cause of dementia in people over 65.. As many as 4 million Americans currently suffer from AD, and as the U.. S.. population ages that number is expected to rise significantly.. Some 10% of people over age 65 are afflicted with AD; of those age 85 or older the incidence increases to 50%.. Frequency: Dr.. Shelanski talks about the frequency of Alzheimer disease in populations of 60.. Aluminum & Alzheimer: Dr.. Shelanski speaks about whether aluminum is a factor associated with Alzheimer disease.. Head injuries & Alzheimer: Dr.. Shelanski talks about certain types of head injuries and how some of the symptoms are similar to Alzheimer.. Preventing Alzheimer Disease: Dr.. Shelanski discusses the relationship between anti-inflammatory drugs and Alzheimer disease.. Identifying Gamma Secretase: Dr.. Shelanski describes the link between gamma secretase and important enzyme in the plaque formation in patients with Alzheimer and mutations of the presenilin genes.. Diagnostic Challenges: Dr.. Shelanski talks about determining the risks for developing AD and the pros and cons of predictive diasgnostics.. Drug Therapy: Dr.. Wisniewski, Associate Professor of nerology, pathology, and psychiatry at New York University School of Medicine, talks about drug therapy to treat memory loss in Alzheimer patients.. Mild cognitive Impairment (MCI): Dr.. Wisniewski talks about the connection between mild cognitive impairment and Alzheimer disease as well as early identification of those with MCI.. MCI and forgetfulness: Dr.. Wisniewski differentiates between MCI and normal forgetfulness associated with aging.. Diagnosis: Dr.. Wisniewski talks about the process of ruling out other causes of dementia in patients with cognitive decline.. Alzheimer & Cell Death: Dr.. Wisniewski explaines why cell suicide may lead to the symptoms seen in Alzheimer disease.. Cholesterol and Alzheimer Disease: Dr.. Wisniewski explains why keeping your cholesterol levels low may be important in preventing Alzheimer disease.. Behavior Changes: Ro Johnson s mother suffers from Alzheimer disease.. Ms.. Johnson recalls when she first noticed something amiss in her mother s behavior.. Modifying Lifestyle: Ro Johnson describes how she undertook the initial steps to assist in her mother s care.. Deterioration: Ms Johnson struggles with her emotions as she describes her mother s decline and how she copes with the losses.. Financial struggles: Ms Johnson discusses the financial strains infolved in coping with Alzheimer disease.. Testing: Ms Johnson talks about the progressive memory testing her mother underwent, and whether she, herself, will undergo testing to determine her genetic risk for Alzheimer disease.. Safe Return: Ms Johnson describes the safe return program for Alzheimer patients and their caregivers.. The diagnosis: Julie Zale was diagnosed with Alzheimer disease in 1998.. She explains what led her to seek a diagnosis for her ongoing mental changes and lists some of the testing involved.. Coming to Terms: Ms Zale explains why being diagnosed with Alzheimer disease brought her a strange sense of relief the relief of finally knowing! Adapting: Ms Xale talks about how she sought to gain knowledge about her disease and support for herself.. Building a team: Ms.. Zale explains how she went about assigning people to handle her affairs as her health declines and the sense of empowerment that brought her.. Family: Ms Zale discusses why she does not wish to burden her daughter with her future care.. Last Days: Ms Zale anticipates the end stages of her disease and talks about the people who will make decisions for her at that point, including when to place her in a care facility..

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  • Title: Duchenne/Becker Muscular Dystrophy - Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: Duchenne muscular dystrophy (DMD) is a genetic disorder that causes progressive muscle weakness as individual muscle cells die.. The cause of DMD's progressive muscle wasting can be traced back to a small mutation in one gene on the X chromosome.. Inside this gene, many separate chunks, called exons, contain instructions for producing an important muscle protein called dystrophin.. Each exon must be read in order, from 'start' to 'end,' to properly construct the protein.. Most boys with DMD (about 75%) are missing one of these exons.. Not only does this remove some of the instructions for making the muscle protein, it also garbles the code inside exons further downstream.. A small bit of the garbled code stops further reading of the gene.. A closer look at this process shows that the stop signal arises because the exon's removal shifts the remaining genetic code out of its usual alignment, as represented by the gray boxes.. After the code shifts, different letters appear in the boxes.. In DMD, one of these boxes contains the code letters T-A-G; this code tells dystrophin production to stop.. As dystrophin's production machinery tries to read the gene s instructions starting at exon 1 and proceeding to exon 75 the new stop signal halts the machine in mid-gene.. Only a shortened version of dystrophin is formed.. Since the rest of the exons are ignored, the dystrophin is much shorter than normal.. The cell recognizes the protein isn t right and immediately degrades it.. In the other cases of Duchenne, all exons are present, but smaller changes in the gene like a change in one letter of code critically alter the shape of the dystrophin protein, or generate a stop signal in the middle of the gene.. (In the latter case, gentamycin may help by letting the dystrophin production machinery skip over the premature stop signal.. ) Without dystrophin, vital connections between proteins in the cell membrane and other proteins inside the cell are lost.. No one knows exactly how, but these changes weaken the membrane of the muscle cell and make it more prone to rupture.. When the membrane ruptures, molecules that normally stay inside the cell flow out, and molecules that normally stay outside the cell flow in.. One of the molecules that flows in (calcium) causes the muscle cell to contract in the area near the damage.. The localized contraction (unlike a contraction along the entire length of the muscle) breaks the fibers inside the cell.. When damage to the cell is severe, the cell dies.. Macrophages and other cells arrive to clean up the remnants.. After the clean-up, many "satellite" cells appear and group together to build a new cell.. Though dead cells are replaced by new ones when a boy is very young, as he gets older the number of dying cells overwhelms the repair capacity of the satellite cells.. The cells simply stop creating new muscle.. Instead, fat and connective tissue fill in the spaces left by the dead muscle cells.. Becker muscular dystrophy (BMD) is a similar disorder that is also caused by a mutation frequently an exon deletion in the dystrophin gene.. The progression of the disorder is much the same except it proceeds more slowly.. The critical difference is that the exon deletion in BMD does not produce a stop signal inside the gene.. A closer look at the exon loss in Becker shows that the stop signal fails to appear, because the genetic code stays in alignment after the deletion.. When the protein production machinery reads the gene, all remaining exons are read to form the protein.. The dystrophin produced from this gene is slightly shorter than normal and does not function as well.. But because it manages to perform some of dystrophin's duties, muscle is lost more slowly than in Duchenne.. If a physician suspects Duchenne or Becker muscular dystrophy after examining the boy, she will use a CPK test to determine if the muscles are damaged.. This test measures the amount of the CPK enzyme (creatine phosphokinase) in the blood.. In a boy with Duchenne or Becker, CPK leaks out of the muscle cells into the bloodstream, so a high level confirms that muscle damage is present.. The level of CPK in the blood can be measured in several different ways.. All of them show that a boy with DMD or BMD will have 50 to 100 times more CPK in his bloodstream than a boy without DMD.. Because most boys with DMD or BMD have lost an exon from their dystrophin gene, a rapid DNA test can quickly identify the missing exon and confirm a diagnosis.. The test produces a vertical "line-up" of the exons within the boy's gene.. When an exon is present, it appears as a dark rectangular-shaped stain at a particular height in the picture.. When an exon is absent, the stain is missing.. The test below shows a boy who's missing exon 50.. This picture is produced after DNA is isolated from a small blood sample taken from the boy.. The test is based on just a small portion of the gene around an exon.. A geneticist can detect the presence of this particular exon by using a chemical reaction called PCR.. In PCR, two short "primers" are added to the boy's DNA sample.. When the exon is present, the two primers attach to the DNA.. The red primer attaches to the right side of the exon, while the blue primer attaches to the left side.. When the exon is absent, the primers fail to attach.. In essence, after the primers attach, the DNA between the two primers is copied millions of times.. Millions of DNA pieces accumulate when the exon is present, but nothing happens when the exon is absent.. The geneticist will see the difference between these two tubes when he concentrates the DNA pieces in one spot in a slab of gel.. In practice, many different pairs of primers each pair specific for a separate exon are thrown into the same reaction mixture with  ...   in the child, and the entire square contains all possible combinations.. Next, we count the boxes that contain the Duchenne-causing genotype (XDY), and divide this number by the total number of boxes.. There is only one Duchenne genotype, so every child of this couple has a 1-in-4 (25%) chance of being a boy with Duchenne.. Each child also has a 25% chance of being a girl who carries the mutated gene (XXD).. The most important thing to remember about these odds is that they apply to every child this couple has.. It may be useful to think of the Punnett square as a roulette wheel.. Each child is a separate "spin of the wheel," so each child has a 25% chance of being a boy with muscular dystrophy (or an unaffected boy, or an unaffected girl, or a carrier girl).. In this family, two out of four children have muscular dystrophy.. Other couples with the mutation may have one, three, four, or even no children with the disorder.. A Punnett Square also shows us the children a man with Becker muscular dystrophy can have.. Usually, his partner will be a woman who does not carry a dystrophin mutation.. As before, we move the parents' chromosomes to the outer edges of the square, and then copy and paste them into the inner boxes.. Two out of four boxes are unaffected boys, so there is a 50% chance this couple will have an unaffected boy (rollover the XY boxes).. The other two boxes contain a carrier (XDX), so there is a 50% chance of having a girl who carries the mutation for Becker muscular dystrophy.. Duchenne muscular dystrophy (DMD) is a typical sex-linked disorder affecting only boys.. Becker muscular dystrophy (BMD) is a milder form of the same disorder.. A boy inherits DMD or BMD when he receives an X chromosome with a mutated dystrophin gene from his mother.. Boys with Duchenne lose muscle throughout their lives, but this is usually not detected until a parent notices unusual walking or running and/or a difficulty talking around the age of 3.. The calves may also be unusually large and firm.. The muscle weakness in Becker is usually noticed later in childhood.. Duchenne muscular dystrophy is the most common of the more than 20 different muscular dystrophies.. About 1 in every 3,500 boys is born with Duchenne, and about 1 in every 18,000 boys is born with Becker a milder form of the disorder.. All ethnic groups are equally affected by both disorders.. Three tests are commonly used to diagnose Duchenne and Becker.. A CPK (or CK) assay will detect muscle damage, but not its source.. A DNA test or muscle biopsy can point directly to Duchenne or Becker.. CPK and DNA tests can also detect many carriers.. Duchenne and Becker muscular dystrophies are caused by a mutation in a gene that produces an important muscle protein called dystrophin.. In Duchenne, no dystrophin is produced, while in Becker, a distorted version is produced.. Without fully functional dystrophin, the muscle cells gradually die.. There are no cures for Duchenne or Becker muscular dystrophies.. Treatment consists of physical therapy to avoid tightening of the muscles, braces and wheelchairs to keep the boy mobile, spinal surgery for scoliosis, and breathing aids.. Steroids may be used to slow the progression of the disorder.. Clinical Features: Dr.. Alfred Spiro discusses the first physical signs of DMD, how a doctor tests muscle strength during an office visit and differences between Duchenne and Becker.. CPK Assay (Flash Animation) This blood test determines if muscles are being damaged by measuring the amount of muscle enzyme (CPK) spilled into the bloodstream.. DNA Testing: A DNA test used after a CPK assay frequently confirms a diagnosis of DMD in boys who are missing an exon.. Muscle Biopsy ( Flash Animation) If the DNA test fails to detect a missing exon, DMD or BMD and be confirmed with a sample of muscle.. Prenatal Testing: Testing prior birth via amniocentesis is not a routine test except in women with a family history of muscular dystrophy.. Initial Reactions: Suzanne Burger and Margaret Cohan discuss their first reactions after getting the diagnosis and how they dealt with it.. Grief and Sadness: Parents of boys with Duchenne discuss cycles of grief and how they cope with the diagnosis.. Support Groups: Support groups can help parents deal with anger, school issues, and personal relationships.. Your friends: Suzanne Burger comments on changing friendships and how to help if a friend has a son with muscular dystrophy.. Your Child s Questions: Margaret Cohan and Suzanne Burger discuss how they answer their sons question and when they give them information.. His Friends: Margaret Cohan discusses her son s friends and what she does to help stimulate new friendships.. Protecting Your Child: Margaret Cohan warms against over-protecting your son and discusses the importance of Joe s activities to her family.. School Advocacy: Getting your son s school to respond to his needs may be hard, but there are groups and people that can help.. Special School Events: Margaret Cohan relates her son s experience on a team building field trip and how the teachers responded.. Wheelchairs: Suzanne Burger and Margaret Cohan discuss planning for the wheelchair and how to make the transition.. Getting Away: Suzanne Burger discusses the importance of getting away with short vacations or through your own activities.. Progression of DMD: Though muscles of the boy are affected by DMD at birth, overt signs are not obvious until the boy is between 4 and 7.. Dr.. Spiro discusses the progression of the disorder after age 7.. Contractures: Dr.. Spiro discusses contractures, the tightening of the boy s joints, and what can be done about them.. Dardiac and Respiratory Muscles: In later stages, heart and breathing-related muscles weaken.. Spiro discusses the first signs of cardiac and respiratory involvement and way to address them.. Slowing Progression: Dr.. Spiro discusses the use of prednisone to slow progression of muscles weakness and Suzanne Burger relates her son s experience with the drug..

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  • Title: Down Syndrome - Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: Children born with Down syndrome (DS) have an excessive amount of the chromosome 21 in some or all of their cells.. This chromosomal abnormality often causes characteristic physical traits in people with DS as well as developmental delays and mental retardation.. Single deep crease across the palm.. Joint Laxity.. Excessive space between 1st and 2nd toe.. Small mouth enlarged tongue.. small nose with depressed nasal bridge.. upward slant to the eyes.. Abnormally shaped ears.. The vast majority of people with DS carry an extra copy of chromosome 21 in every cell in their bodies.. Normally, human cells all contain 23 pairs of chromosomes for a total of 46.. AN UNAFFECTED MALE KARYOTYPE: 46, XYA MALE DOWN SYNDROME KARYOTYPE: 47, XY, +21There are three genetic forms of Down syndrome: non-disjunction, mosaicism, and translocation.. Non-disjunction is the most common, and individuals with this form have an entire extra chromosome in all their cells.. Non-disjunction is a result of faulty chromosome separation during cell division in egg or sperm cell production.. This type of cell division is called meiosis.. As the cells divide, the 23 pairs of chromosomes are supposed to split up and head to opposite sides in the dividing cell.. (In the cell below, only one chromosome pair is shown.. ) Meiosis involves a series of stages that ultimately reduce the number of chromosomes from 46 to 23.. Meisois ensures that the resulting gametes, sperm or egg cells, will have 23 single chromosomes.. (In cells below, we only show one chromosome.. But remember, there are actually 23 in each newly formed cell.. ) When fertilization occurs, the resulting embryo will have a total of 46 chromosomes ø 23 pairs.. But things can go wrong during meiosis.. The initial stages of meiosis may run smoothly.. however; sometimes in later stages, one pair of chromosomes fails to separate and both chromosomes go to one side of the dividing cell.. This cell-division mistake is called non-disjunction.. When non-disjunction occurs, the resulting gametes will have an abnormal chromosome count.. One cell will have 22 single chromosomes and the other will have 24.. Non-disjunction results in Down syndrome when an egg or sperm cell with two 21 chromosomes merges with a normal mate (one 21 chromosome).. 24 SINGLE CHROMOSOMES IN EGG CELL 23 SINGLE CHROMOSOMES IN SPERM CELL As the embryo develops, the extra 21 chromosome is replicated in every cell of its body.. Fertilization of an egg cell by a faulty sperm cell can cause Down syndrome, but recent research implicates abnormal egg cells in the majority of cases.. Despite years of research, no one knows what causes non-disjunction to occur.. Mosaic Down syndrome (mosaicism) is rare and accounts for only 1% to 2% of those with DS.. As the name implies, those affected have a mixture of cell types in their bodies.. Some cells are normal and contain 46 chromosomes, while others contain 47, carrying an extra copy of chromosome 21.. Mosaic DS is further sub-divided by how the mixture of cells occurs in the body.. When different cells of the same type are mixed this is called cellular mosaicism.. NERVE CELLS WITH 46 CHROMOSOMES NERVE CELLS WITH 47 CHROMOSOMES When one set of cells (kidney for example) has the normal number of chromosomes, and another cell set (say nerve cells) has an extra chromosome 21, this is called tissue mosaicism.. NERVE CELLS WITH 47 CHROMOSOMES KIDNEY CELLS WITH 46 CHROMOSOMES Mosaicism results from a non-disjunction error that occurs immediately after fertilization.. Recent research seems to indicate that the majority of cases of mosaicism happen when a zygote with the most common form of DS (non-disjunction trisomy 21) loses the extra 21 chromosome in certain dividing cells.. This creates "lineages" of cells with or without the extra chromosome.. The third form of DS results from what is known as a Robertsonian translocation, and accounts for approximately 4% of DS cases.. Translocation DS occurs when part of the chromosome 21 breaks off during meiotic cell division and latches onto another chromosomal body (usually number 14).. When a gamete with such a translocation error merges with a normal egg or sperm cell, the result is a triplication of chromosome 21 material.. However, because the extra portion of chromosome 21 is fused with chromosome 14, the total number of chromosomes in each cell is a normal count of 46.. Translocations resulting in DS can either be sporadic, chance events of faulty cell division or may be inherited.. TRANSLOCATION KARYOTYPE Doctors often suspect the diagnosis of Down syndrome at birth from the physical appearance of the newborn.. When Down syndrome is suspected, a genetic test is done to study the baby's chromosomes.. This test is called a karyotype, and it represents the entire chromosomal makeup of an individual.. To perform a karyotype, cells that divide often are needed.. Because lymphocytes divide readily and are easy to obtain from blood, these cells are frequently used to test for Down syndrome.. Heparin, an anti-clotting agent, is added to this blood sample, which is then put into a centrifuge.. The blood sample is then spun in the centrifuge, thus separating out the various blood cell types.. Once separated, these lymphocytes are placed on a growth culture and encouraged to divide (undergo mitosis).. Because dividing cells show off their chromosomes best at the mid-stage of cell division called metaphase, a drug is added to the dividing cells to halt  ...   baby with Down syndrome.. When a woman with Down syndrome produces egg cells during meiosis, half of her eggs will have an extra 21 chromosome.. Thus, if fertilization occurs there is a 50% chance that her fertilized egg will contain an extra chromosome 21.. Most cases of Down syndrome result from faulty gamete cell division and are not inherited.. But a small percentage of those with Down syndrome did inherit the chromosomal defect from either their mother or father.. Inheritance symptoms treatment incidence cause testing and screening Children born with Down syndrome vary widely in their symptoms.. The most common symptoms include: mental retardation, an upward slant to the eyes, decreased muscle tone, flattened facial profile with depressed nasal bridge and small nose, small mouth and abnormal shape to the ears, and laxity around the body s joints.. Down syndrome (DS) is one of the most commonly occurring genetic birth defects, and it is the most common genetic reason for mental retardation.. About 1 in 900 people are born with this disorder.. Because of higher fertility rates in younger women, the majority of DS children are born to mothers under 35 years of age; however, the likelihood of having a child with DS increases with advancing parental age.. Prenatal testing can be done to determine if a fetus has Down syndrome (DS).. Babies born with DS usually have physical characteristics that lead to a suspicion of the disorder.. Diagnosis is confirmed with a test called a karyotype that gives a complete picture of an individual s chromosomes.. People with Down syndrome (DS) have an excess, or redundancy, of genetic material in their cells specifically, an excess of chromosome 21.. The vast majority, approximately 95%, have a complete extra chromosome 21.. Others with DS, 4%, have an extra bit of chromosome 21 attached or translocated onto another chromosome usually chromosome 14.. And some, 1%, have a mixed or mosaic pattern of cells in their bodies where some cells have normal amounts of genetic material and other cells have an extra chromosome 21.. There is no cure for Down syndrome (DS) nor are there effective medical treatments at the present time.. However, because of conditions common to those with DS, such as heart defects, hearing deficits, and developmental delays, good medical and supportive care is essential to this population.. How is Down syndrome diagnosed? Characteristics: Dr.. Judith Willner, the Director of Clinical Genetics at Mount Sinai School of Medicine in New York, discusses the typical characteristics of those born with Down syndrome (DS).. Intelligence quotients: Dr.. Willner talks about intelligence quotients and mental retardation in people with Down syndrome.. Genetic Counselors: Ms Zinberg, Director of Genetic Counseling at Mount Sinai School of Medicine in New York, discusses the role genetic counselors play in helping families understand and cope with Down syndrome.. Prenatal Testing for DS: Ms Zinberg talks about chorionic villus sampling (CVS) and amniocentesis procedures as ways to diagnose DS in a fetus.. Risks of Prenatal Testing: Ms Zinberg talks about risk of spontaneous abortion associated with chorionic villus sampling and amniocentesis.. CVS vs.. Amniocentesis Ms Zinberg discusses women s choices in determining which prenatal test is best for them.. (CVS is typically performed between 8 and 12 weeks of gestation; amniocentesis, between 12 and 20 weeks.. ) New DS Prenatal Test: Dr.. Willner discusses a new testing technique being studied that is less invasive and can be done early in the pregnancy.. How is down syndrome treated? Treatment Dr.. Judith Willner, the Director of Clinical Genetics at Mount Sinai School of medicine in New York, discusses treatment options for those with Down syndrome (DS).. Monitoring Dr.. Willner talks about the importance of monitoring those with DS for specific health problems.. Hypothyroidism Dr.. Willner talks about hypothyoidism in people with Down syndrome.. Alzheimer an DS Dr.. Willner explains why those with Down syndrome are at increased risk for developing Alzheimer disease.. Theory Dr.. Willner puts forth a theory as to why older women are more likely to carry a DS pregnancy to term.. What is it like to have Down syndrome? Diagnosis: Jim and Sheila McHale share their feelings and experiences upon learning that their first child had Down syndrome.. Child with DS The McHales discuss the evolution of their feelings in raising a child with Down syndrome.. Telling Others Jim McHale explains his sensitivity to others reactions upon learning that three of his children have Down syndrome.. Adoption The McHales talk about the youngest of their two adopted children with Down syndrome, Kate.. The Future Jim and Sheila McHale discuss the future of their children with DS.. Everyone s Own Life The McHales talk about all their children and how each should live their own life.. School The McHales share their thoughts on whether or not to mainstream children with DS into traditional classrooms.. Group Home Jeanne McHale is the oldest daughter of Jim and Sheila McHale.. She and her father discuss her transition to the group home setting and some of her experiences there.. Boyfriend Jeanne McHale and her father talk about Jeanne s boyfriend.. Family Trip Kate McHale is one of two children with DS that Jim and Sheila McHale adopted.. She and her mother recall their trip to Disney World.. Sexuality Sheila McHale discusses the sexuality of her children with DS and her oldest daughter s male friendships.. Jeanne McHale has a long-time boyfriend, Peter..

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  • Title: Fragile X Syndrome - Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: All the symptoms of Fragile X can be traced back to a mutation in one gene called FMR1 on the X chromosome.. People who have Fragile X carry an FMR1 gene that is much bigger than usual.. The gene is bigger in a region where three bases CGG are repeated.. The number of repeats varies from person to person, usually ranging from 7 to 60 repeats in people without Fragile X.. The most common version of the gene has 30 repeats.. People with Fragile X have 200 or more repeats.. In this case, the gene is called a "full mutation.. " When there are so many repeats in the gene, other molecules called methyl groups attach to the cytosine (C) bases in the repeats.. The added methyl groups inactivate, or "turn off," the gene, and the gene fails to produce its protein FMRP (Fragile X Mental Retardation Protein).. Without this protein, a person develops the mental impairment and other characteristics of Fragile X.. Exactly how this happens is unclear, but scientists believe FMRP helps produce other proteins.. Without FMRP, these other proteins are never made.. In the following audio sections, Fragile X researcher Dr.. Esther Nimchinsky explains how the absence of these proteins affects cells in the brain.. Ironically, when we re young, we have more connections between our brain cells than when we're older.. As we grow and mature, unnecessary connections are cut in a process called pruning.. In people with Fragile X, the connections are not pruned.. Geneticists frequently use two DNA tests to diagnose Fragile X.. Both of these tests measure the size of the FMR1 gene but they cover different ranges.. One test PCR detects normal-sized genes and pre-mutations, while the other Southern blot detects larger, full mutations.. The patient need only supply a blood sample to take both tests.. Technicians isolate and purify the DNA from the white blood cells after the sample is sent to a lab.. First we'll explain the PCR test.. In this test, a small segment of DNA containing the FMR1 gene is isolated from the sample and copied millions of times.. The next procedure in the test measures the size of the gene.. The geneticist loads the DNA into the top of a slab of gel.. (The gel looks remarkably like Jello but doesn't taste as good).. Several different samples can be loaded into the same gel.. After the samples are loaded, electric current "pushes" the DNA fragments down the length of the gel.. (Not sideways, not up, just down).. As the pieces move down the gel, they wind their way through the tangled gel matrix.. Small pieces do this easily so they zip through the gel quickly.. Big pieces have a harder time so they move more slowly.. After a set period of time, small pieces have migrated to the bottom of the gel, while big pieces have remained near the top.. The DNA is invisible but shows up as dark "bands" after it is dyed.. This is a real gel showing DNA from two males.. (Males have one X chromosome, so they only have one band).. The male on the left, with the lower band, has the smaller number of repeats.. The male on the right has a larger gene (a pre-mutation) with more repeats.. The female patterns are more complicated.. Each female has two bands representing her two X chromosomes.. The first female has two normal-sized genes with slightly different numbers of repeats.. The second female has one normal-sized gene and one pre-mutation with about 58 repeats.. Though the PCR test can pick up normal-sized genes and pre-mutations, it can't detect full mutations (200 or more repeats).. Geneticists use another test Southern blot analysis to detect these larger mutations and diagnose Fragile X.. Though the details differ from the PCR test, the gist of the test remains the same: measuring the size of the FMR1 gene.. First, enzymes cut the DNA on both sides of the gene.. In the diagram below, the enzymes free a small fragment containing a FMR1 gene with 7 repeats.. In the diagram below, the enzymes free a small fragment containing a FMR1 gene with seven repeats.. When the FMR1 gene has 200 repeats or more, the enzymes free a much larger fragment.. In essence, identifying a person with Fragile X is easy.. The geneticist simply looks for the presence of this very large fragment on a gel.. The large DNA fragment with a full mutation shows up as a fuzzy smear above the dark blue line.. The line is a size marker.. The blue arrow points to a male with a full mutation (notice he has no other bands), and the red arrow points to a female with a full mutation.. She has additional bands representing her other X chromosome.. If you're wondering why the full mutation band is so much fuzzier than the others (and if you're not you can quit now), the answer lies in the source of the DNA.. Each band is filled with DNA from many different cells.. When every cell in the sample contains the same-sized gene, all the DNA fragments migrate to the same spot in the gel, and make a distinct band.. When cells have different-sized FMR1 genes as the cells of most people with Fragile X do the sample contains DNA fragments of various sizes.. These migrate to different locations, and the end result is a diffuse smear.. Fragile X is just like any other sex-linked disorder, because the "Fragile X" gene (FMR1) is on the X chromosome.. The X is one of two types of sex chromosomes: X and Y.. A girl has two X's, and therefore, she has two copies of the FMR1 gene.. If one is mutated, she can fall back on the unmutated copy.. A boy has only one X.. If he has a mutated copy, he has no other copy to fall back on.. A boy gets Fragile  ...   does not necessarily develop Fragile X.. ) When the mother carries a pre-mutation on one of her X chromosomes, she also has a 50% chance of passing the pre-mutation to her child.. Remember, though, that the pre-mutation can expand into a full mutation in the early embryo.. The chance of this happening depends on the number of repeats in the pre-mutation.. Let's say the mother has a pre-mutation with 65 repeats.. To calculate her chance of having a child with a full mutation, we multiply the chance of having a child with a pre-mutation (50%) by the expansion risk, in this case 17%.. If the mother has a different number of repeats in her pre-mutation, we repeat the math to find out her odds of having a child with a full-sized mutation.. (Remember, though, a girl with a full mutation does not necessarily develop Fragile X.. ) The most important thing to remember about these numbers is that they apply to every child this couple has.. This concept is easiest to understand when we consider the following couple that has a 50% chance of passing a full mutation to their child.. Each child is a separate "spin of the wheel," so each child has a 50% chance of receiving the full mutation.. In this example, one in four children has Fragile X.. It's also possible that this couple could have four unaffected children or four children with Fragile X.. Notice what the 50% chance does not mean.. It does not mean that precisely 50% of this couple's children will have the full mutation.. And it does not mean that a second child will have a full mutation if the first one lacks it.. (Or vice versa; it does not mean that a second child will lack the full mutation if the first child has it.. ) Fragile X gets its name from the broken appearance of the X chromosome in people with the disorder.. The break is where the Fragile X gene, FMR1, is found.. Fragile X individuals are mentally impaired, with problems ranging from slight learning disabilities to severe mental impairment.. They may be hyperactive and hyper-sensitive to external stimuli and have short attention spans.. Physically, a Fragile X individual may have a long, narrow face, prominent ears, nose and forehead, enlarged testicles and loose joints.. Fragile X is the most common inherited cause of mental impairment.. An estimated 1 in 2,000 boys are mentally impaired because of Fragile X.. Girls are also affected, but the incidence rate is lower and the effects are usually milder.. DNA tests identify persons with the disorder and women who are carriers.. Approximately 1 in 260 women carry a pre-mutated FMR1 gene.. Fragile X is caused by a mutation in the FMR1 gene on the X chromosome.. The mutation turns off the production of the FMR1 protein, which is implicated in the development of neuronal connections in the brain.. There is no known cure for Fragile X.. Current drug therapies are available to improve attention span and decrease hyperactivity.. Early intervention and special education programs, including speech and physical therapy, are often beneficial.. Treatment Facts and Theories Symptoms Incidence Cause Testing and Screening What is it? What causes it? How is it inherited? How is it diagnosed? What is it like to have it? For more information Acknowledgments Overview of Treatments Dr.. Ted Brown, Director of the New York State Institute Developmental Disabilities, talks about the treatments available to ameliorate Fragile X symptoms.. Occupational Therapy Dr.. Vicki Sudhalter, a clinical psycholinguist, talks about the need for occupational therapy, whick improves the physical coordination of children with Fragile X.. Speech Therapy Classical methods of teaching language do not work with Fragile X children.. Vicki Sudhalter talks about how speech therapy can help.. Behavior Therapy Dr.. Vicki Sudhalter talks about therapy of the most prevalent behavior: anxiety.. Medicines Drugs that regulate hyperactivity and anxiety help 90% of children with Fragile X, according to Dr.. Vicki Sudhalter.. Gene Therapy Prospects Inserting a new gene into people with Fragile X may provide a complete treatment in as soon as ten years.. Early Symptoms Dr.. Ted Brown, director of the NYS Institute of Developmental Disabilities, talks about early symptoms in Fragile X individuals.. Katie Clapp and Debbie Stevenson talk about symptoms in their sons, Andy and Taylor.. Behavioral Severity Debbie Stevenson and Dr.. Ted Brown talk about the severity of behaviors in Fragile X individuals.. Kinds of Behavior Katie Clapp and Michael Tranfaglia talk about different kinds of behavior in Fragile X individuals and in their son, Andy.. Dealing with Meltdowns Debbie Stevenson and Michael Tranfaglia talk about meltdowns (tantrums) in their sons, and how to deal with them.. Dealing with others Datie Clapp talks about how strangers react to her son Andy, and what she does about it.. Laura Tranfaglia talks about her friends reactions to her brother, Andy.. Laura Tranfaglia talks about her brother, Andy, who has Fragile X.. Debbie Stevenson talks about how her son, Taylor, who has Fragile X, interacts with her son, James.. Blame and Guilt Katie Clapp and Michael Tranfaglia talk about their feelings of blame and guilt for their son, Andy, who has Fragile X.. Family History Dr.. Ted Brown talks about the family history of individuals with Fragile X.. Mary Lou Supple and Debbie Stevenson talk about Fragile X in their extended families.. Telling Family Katie Clapp and Debbie Stevenson talk about telling other family members and helping them understand their risk of having a child with Fragile X.. Older Kids Mary Lou Supple talks about her 13-year old son, James, who has Fragile X.. Michael Tranfaglia talks about older children and adults with Fragile X.. Expectations Katie Clapp, Debbie Stevenson, and Mary Lou Supple talk about their expectations for their sons: Andy, Taylor, and James, who have Fragile X.. Future Debbie Stevenson, Michael Tranfaglia, and Katie Clapp talk about planning for the future of their children with Fragile X..

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  • Title: Marfan Syndrome- Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: Marfan s syndrome Marfan syndrome is a disorder that weakens the connective tissue of the body.. Connective tissue is not a single entity, but a catch-all term for everything in your body that keeps you from falling apart.. The familiar tendons and ligaments keep bones and muscles together, but other connective tissue is more obscure, like the elastic fibers in the aorta that keep it soft and rubbery.. Even bone is a connective tissue.. Marfan syndrome affects all of these structures.. People with Marfan syndrome have loose tendons and ligaments, less elasticity in the aorta, and longer arms and legs.. All of these seemingly unrelated characteristics are caused by a mutation in a single gene on chromosome 15.. The gene is named FBN1 for the protein it encodes, fibrillin-1.. The precise order of the A's, C's, T's, and G's in the gene determines the composition of the protein.. The cell's protein-production machinery embodied by the funny green guy reads the code in the gene and then adds the proper amino acid to the growing protein.. Each amino acid is encoded by a different 3-letter code.. The gene produces lots of copies of the fibrillin protein, and these join together with other components to form a long, stringy structure called a microfibril.. In people with Marfan syndrome, a mutation (a misspelling) in the gene changes the shape of the fibrillin protein.. There are many mutations that can cause Marfan syndrome, but most are single letter changes that lead to a single amino acid change in the protein.. The change in the amino acid alters the shape of the fibrillin proteins.. The irregularly-shaped proteins then assemble into an irregularly-shaped microfibril.. Microfibrils show up in all kinds of connective tissues, but for people with Marfan syndrome, the microfibrils in the aorta are most important.. In the wall of the aorta (the large blood vessel that carries blood out of the heart), microfibrils combine with elastic fibers to make the aorta stretchy.. When the heart ejects blood into the aorta, the force of the propelled blood causes the vessel to expand, stretching the elastic fibers.. The elastic fibers then return to their original size, bringing the aorta back to its unstretched diameter.. In people with Marfan syndrome, the microfibrils do not help the elastic fibers spring back, and the aorta gets stretched out over time (like an old rubber band) by the force of the blood.. As it widens, the aorta also weakens.. This puts people with Marfan syndrome at risk for aortic dissection, a tear in the vessel s inner layer.. In a dissection, blood flows into the space between the layers of the aorta.. The blood pools and may block normal blood flow through the vessel.. An untreated dissection will form an aneurysm, weakening the outer wall and leading to a complete rupture of the aorta.. A complete rupture is usually fatal.. Mitral valve prolapse, a type of heart murmur, is another common cardiovascular condition in people with Marfan syndrome.. In mitral valve prolapse, the flaps between the left atrium and the left ventricle are too big and floppy.. The flaps normally keep blood from flowing backward into the left atrium when the heart contracts.. When the flaps are too big and floppy, they don t close properly, and some blood can flow back into the left atrium.. This is called regurgitation.. When the backflow is large, blood flow to the rest of the body decreases, and the heart may pump harder to compensate.. If the heart is working too hard, it can eventually fail.. Cardiovascular health is the main health concern of people with Marfan syndrome, but skeletal problems can also be debilitating.. People with Marfan syndrome are frequently tall and skinny, with disproportionately long arms and legs, from faster bone growth.. As bones grow, they pull on the ligaments that connect one bone to another.. The combination of fast bone growth and weak microfibrils in people with Marfan syndrome stretches their ligaments out.. The ligaments become too loose to keep vertebrae in place, and the vertebrae get out of line.. (Similar loose ligaments in the fingers cause "double-jointedness").. A side-to-side curve to the spine is called scoliosis.. The spine may also bend forward or backward away from its natural curvature.. When the curve is severe, the spine can impinge on the lungs and impair breathing.. People with Marfan syndrome are also frequently near-sighted due to elongated eyeballs that move the retina away from the focused image.. A more unique problem is lens dislocation, where the ligaments centering the lens  ...   inheriting Marfan syndrome is also 2 out of 4, or 50%.. The same chance applies in the opposite situation when the woman has the Marfan mutation and the man does not.. Two out of four boxes contain the Marfan-causing combo (Mm or mM), so the chance of this couple's child inheriting Marfan syndrome is also 2 out of 4, or 50%.. It may be useful to think of the Punnett Square as a roulette wheel.. Each child is a separate "spin of the wheel," so each child has a 50% chance of receiving the mutation.. In this family, one in four children has Marfan syndrome.. Other couples with the mutation may have two, three, four, or even no children with Marfan syndrome.. What is it? What causes it? How is it inherited? How is it diagnosed? How is it treated? What is it like to have it? For more information Acknowledgments Facts and Theories Many people think that Abraham Lincoln had Marfan syndrome based on his lanky body and the fact that a distant relative had the disorder.. DNA tests are not yet good enough to confirm or refute this suspicion.. Symptoms People with Marfan syndrome have weak connective tissues in the heart, skeletal system, eyes and other organs.. The aorta may enlarge, the spine may curve and the eye lens may dislocate.. These symptoms are quite variable among people with Marfan syndrome and can range from mild to severe.. Marfan syndrome affects both sexes and all ethnic groups, but it is relatively rare.. About 1 in 5,000 people are born with the disorder.. Physicians familiar with marfan syndrome make a diagnosis based on the co-existence of several features.. There are no DNA- based tests for diagnosis, because nearly every family with Marfan syndrome has their own unique mutation in the fibrillin gene.. Marfan syndrome is a genetic disorder caused by a mutation in the fibrillin gene.. The misshapen fibrillin produced fom the mutated gene weakens the tendons, ligaments, and other connective tissues in the body.. Treatment for cardiovascular problems is critical, and the aorta must be monitored for weakness.. Drugs can help reduce the stress experienced by the aorta, but surgery may be needed eventually to replace the vessel.. Variability of Symptoms Dr.. Richard Devereux is a cardiologist at the New York Presbyterian Hospital.. He talks about the variability of symptoms among people with Marfan syndrome.. Physical characteristics.. Devereux lists some of the physical characteristics associated with Marfan syndrome.. Diagnosis Dr.. Devereux talks about how he would proceed with a Marfan syndrome diagnosis.. DNA Diagnosis Since the fibrillin gene has been cloned, Dr.. Devereux discusses the development and use of DNA tests for diagnosis.. Diagnosis in Children Dr.. Devereux talks about how to diagnose children with Marfan syndrome, specifically comparing the length of growing bones.. Aortic Dissections Dr.. He talks about the dangers of aortic dissections and the various treatment options.. Elective Heart Surgery Dr.. Devereux discusses surgery as an option for those who have enlarged aortas.. Preventing Heart Problems Dr.. Devereux talks about ways to reduce stress on the aorta and the heart.. Eye Conditions Dr.. Devereux discusses the possibility of eye problems, such as lens displacements, in people with Marfan syndrome.. Skeletal Problems Dr.. Devereux talks about skeletal problems common among people with Marfan syndrome.. Skeletal Treatments Dr.. Devereux talks about different ways to deal with skeletal problems.. Medication Joe Gagliano, president of the National Marfan Foundation (NMF), and Julie Kurnitz talks about adjusting to the medications they take.. Exercise Joe Gagliano talks about the need to balance the level of exertion and physical activity with quality of life.. Managing Healthcare Joe Gagliano and Julie Kurnitz talk about the need for extra specialists to treat Marfan syndrome.. A team of doctors is necessary for this multi-system disorder.. Educating Others Julie Kurnitz talks about the need for people to be aware of the serious health risks of Marfan syndrome, and what she has done to try to raise awareness.. Post-diagnosis Feelings 1 Joe Gagliano and Julie Kurnitz talks about how they felt after being diagnosed with Marfan syndrome.. Post-diagnosis Feelings 2 Joe Gagliano and Julie Kurnitz talks about how they dealt with their feelings after being diagnosed with Marfan syndrome.. Support Julie Kurnitz talks about Marfan support groups: the information and the emotionl support they can provide.. Parental Guilt Joe Gagliano talksabout how his father felt knowing that his children inherited Marfan syndrome from him.. Abraham Lincoln Richard Devereux, professor of medicine at Cornell University, talks about evidence that historical figures, like Abraham Lincoln, had Marfan syndrome..

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  • Title: Hemophilia - Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: Hemophilia is caused by a dysfunctional or absent blood-clotting protein.. Without this protein, stable clots do not form quickly over wounds.. Weak clots form, but they are easily dislodged, so that people with hemophilia can bleed for days as clot after clot is dislodged from place.. To understand why these changes cause hemophilia, and to understand the difference between hemophilia A and hemophilia B, we need to look at the details of clotting.. The clotting process starts after the wall of a blood vessel is breached.. The vessel constricts to reduce blood flow, and the platelets (bits of larger bone marrow cells) congregate at the damaged site.. Though the platelets stop the bleeding, at this stage they are easily dislodged, and bleeding can resume.. As the platelets arrive, molecules released from the damaged vessel activate clotting Factor 12.. Factor 12 then activates another clotting protein by snugly fitting into the molecule, as a key fits inside a lock.. Activated thrombin then snips small pieces off another protein called fibrinogen.. When lots of fibrinogen is cut, the pruned molecules cover the platelets and stabilize the clot.. To form a stable clot, all the molecules in the cascade must be present and properly shaped.. In people with mild or moderate hemophilia A, Factor 8 is present but has a slightly dysfunctional shape that sometimes doesn't fit into the next molecule.. Because the mutated Factor 8 succeeds in activating Factor 10 some of the time (doctors say its activity is between 5 and 35 percent of normal), people with mild or moderate hemophilia A don't bleed as long when injured and only rarely, or never, bleed spontaneously.. People with mild hemophilia A have mutated Factor 8 proteins.. This is due to a small mutation in their Factor 8 gene, located on the X chromosome.. The gene's code carries the instructions for building the protein, so a minor change in the instructions causes a minor change in the shape of the protein.. For people with severe hemophilia A, Factor 8 is usually absent, and the clotting cascade comes to a complete halt.. Factor activity is less than one percent of normal.. People with severe hemophilia A bleed spontaneously and can bleed for days after minor injuries.. In people with severe hemophilia A, Factor 8 is not present, because their gene contains a much bigger mutation, like an inversion, that completely garbles the instructions for the protein.. No Factor 8 can be produced from the garbled gene.. When Factor 8 is normal, but the person still has hemophilia, a change in Factor 9 is usually the culprit.. The disorder is called hemophilia B.. In mild or moderate hemophilia B, a small mutation in the gene leads to a slightly dysfunctional Factor 9.. The protein works occasionally to activate thrombin, and stable clots are eventually formed.. When hemophilia B is severe, a more critical mutation in the gene completely misshapes the Factor 9 protein.. The protein either can not be activated or can not activate the next molecule in the cascade.. Before effective treatments were developed in the late 1960s, people with severe hemophilia died young (median age 11) from bleeding.. With effective treatment, life expectancy is nearly normal, but repeated bleeding episodes can cause disabling arthritis in the joints.. Damage to the joints (mainly knees, elbows, and ankles) starts when the synovium a thin lining inside the joint capsule thickens to absorb blood lost from the vessels.. As the synovium thickens, it also acquires more blood vessels that make the joint prone to further injury.. Another injury means more blood to absorb, and the synovium thickens again.. With frequent re-injuries, the synovium never shrinks and remains swollen.. Enzymes from the swollen synovium eat away at the cartilage that cushions the ends of the bones in the joint.. The longer the synovium stays swollen, the more damage occurs.. Eventually, the cartilage is eaten away, and bone begins to grind against bone, causing pain and reducing the joint's range of motion.. Before making a diagnosis of hemophilia, a doctor will have to perform several blood tests to rule out other disorders that share symptoms with the disorder.. The final blood test a Factor activity test confirms the person has hemophilia and also determines the type (A or B) and severity.. This test determines how well each Factor performs relative to that of an unaffected person.. A fully functional Factor has 100% of normal activity, while a completely non-functional Factor has 0% of normal activity.. The amount of activity determines the severity of the disorder.. The technical details of the test involve separating the patient's blood sample into red blood cells and plasma, and then adding a sample of the patient's plasma to another tube of normal plasma.. But first, Factor 8 (represented by the blue dots) is removed from the normal plasma.. A sample of the patient's plasma is then added to the tube.. When the patient has hemophilia A, and therefore little or no Factor 8, the test tube still lacks sufficient amounts of the clotting protein.. After a reagent is added to start the clotting cascade, white blood cells begin to clump together and form clots, which sink to the bottom.. When the patient has hemophilia A, the absence of Factor 8 slows this process.. If the patient has hemophilia B instead, his blood contains a normal amount of Factor 8, and the plasma clots quickly after the clotting reagent is added.. To confirm the diagnosis of hemophilia B, another test measures the activity of Factor 9.. This test is exactly the same as the hemophilia A test, except Factor 9 (represented by the red dots) is removed from the normal plasma instead of Factor 8.. When the patient has hemophilia B, his plasma does not add any (or much) Factor 9 to the tube after a sample is transferred.. Because there is little Factor 9 in the tube, clots form slowly, and the patient is diagnosed with hemophilia B.. Once one person in a family has been diagnosed with hemophilia, it may be desirable to pinpoint the mutation so  ...   partner.. Each parent donates only one of their two sex chromosomes to the child, so we place one of the father's and one of the mother's into each box.. Each box, or genotype, is equally likely, so there is a 1-in-4 (25%) chance that this couple will have a boy with hemophilia (rollover the XHY combo).. There's also a 25% chance this couple will have an unaffected boy (XY), an unaffected girl (XX), or a girl who is a carrier (XXH).. Each child is a separate "spin of the wheel," so each child has a 25% chance of being a boy with hemophilia (or an unaffected boy, or an unaffected girl, or a carrier).. In this family, two out of four children have hemophilia.. A Punnett Square also shows us the potential children a man with hemophilia can have.. Usually, his partner will be a woman who does not carry the mutation.. The other two boxes contain girls who carry the hemophilia mutation (XHX), so there is also a 50% chance this couple will have a girl who is a carrier.. In the early 1980s, most people with hemophilia were infected with HIV, because the factors used for treatment were isolated from infected human plasma.. Since then, virus-sterilizing techniques and the use of artificial factors have greatly reduced this risk.. People with hemophilia bleed longer because their blood does not clot well.. Without treatment, a person with severe hemophilia can bleed to death.. With treatment, internal bleeding in the joints is the most problematic complication, because it leads to painful arthritis.. Hemophilia is a sex-linked disorder that affects males of all races and ethnic groups.. About 1 in 4,000 males are born with the disorder.. Females can have the disorder but it is significantly rarer.. A physician will use several blood tests to rule out other blood disorders before diagnosing hemophilia.. The final test determines which factor is responsible and the factor's activity level.. Genetic testing can uncover carriers and people with mild hemophilia.. Hemophilia occurs when a person has a mutation in one of the clotting factor genes.. Approximately 90% have a mutation in the Factor VIII gene (hemophilia A), 9% have a mutation in the Factor IX gene (hemophilia B), and 1% have a mutation in another clotting gene.. People with hemophilia inject themselves with purified clotting factors to prevent or stop bleeding episodes.. Additional treatment is necessary if the person's immune system attacks the injected clotting factors.. What is it? What causes it? How is it inherited? How is it diagnosed? How is it treated? What is it like to have it? For more information Acknowledgments Characteristics Dr.. Catherine Manno, Associate Director of the Hemophilia Program at the Children s Hospital of Philadelphia, talks about bleeding episodes and two kinds of hemophilia.. Symptoms Dr.. Catherine Manno talks about symptoms in infants.. Bleeds Dr.. Catherine Manno talks about delaying bleeding and other kinds of bleeding.. Mutations Dr.. Catherine Manno talks about the severity of levels of hemophilia and the relation of severity levels to mutations.. Factor Therapy Dr.. Catherine Manno recommends recombinant concentrates.. She discusses what it does and the age at which it would be used.. History Dr.. Catherine Manno discusses how treatments have evolved due to the risk of virus transmission.. Easier Injections Dr.. Catherine Manno talks about surgically implanted solutions and their risks.. Spontaneous Bleeds Dr.. Catherine Manno discusses spontaneous bleeds and locations in the body.. Inhibitors Dr.. Catherine Manno talks about the risks of developed antibodies and the treatments for them.. Joint Disease Dr.. Catherine Manno talks about chronic joint disease and its treatments.. Mild Cases Dr.. Catherine Manno talks about how desmopressin acetate (DDAVP) can be used to release stored Factor 8 in cases of mild hemophilia.. Gene Therapy Dr.. Katherine High, Medical Director of the Coagulation Laboratory at The Children s Hospital of Phladelphia, talks about gene therapy and why hemophilia is a good model disease.. Type B vs.. A Dr.. Katherine High explains the differences between hemophilia A and hemophilia B.. AAV Dr.. Katherine High talks about the advantages of using adeno-associated virus (AAV).. Immune Response Dr.. Katherine High discusses issues concerting the development of inhibitors.. Muscle vs.. Liver Dr.. Katherine High explains the difference between injecting the vector intramuscularly and injecting the vector directly into the liver.. Dog Trials Dr.. Katherine High discusses results from working with hemophilic dogs to test the adeno-associated virus (AAV).. Germline Transfer Dr.. Katherine High talks about conflicts concerning delivering the vector to reproductive cells.. Timeline Dr.. Katherine High discusses the timeline in which their method of gene therapy must be validated so that it can be available to everyone.. Bleeds and Treatments Paul talks about the experience of bleeds and how he prefers episodic treatment.. Greg Price and his mother Linda talk about Prophylaxis treatment and how bleeds may occur.. Advice for Parents (1) Paul supports the idea of a hemophilic child exploring his or her own boundaries of physical activity.. Greg Price and his mother discuss physical freedom.. Advice for Parents (2) Linda Price talks about issues concerning the manufacturers of treatments.. Benefits of Summer Camp Greg Price explains how camp gave him exposure to illnesses other than hemophilia.. Paul recalls how he found companionship with people who dealt with similar difficulties.. Friends and School Greg Price talks about his experiences in school.. Paul sometimes felt left out of the crowd because of hemophilia.. Injections Paul explains how his mother would inject him when he was an infant.. Linda Price talks about her son s self-injections.. Paul talks about learning to inject himself at a camp in Colorado.. Expenses and Insurance Linda Price talks about issues concerning insurance and how only specific job positions will offer the insurance coverage they need.. Carrier Testing Linda Price discusses the importance of carrier testing and her concerns for relatives.. Treatment Centers Dr.. Catherine Manno talks about the advantages of a hemophilia treatment center.. Greg Price and his mother discus the treatment center that they attend.. Diagnosis Feelings Linda Price speaks about the unexpectedness and the life-changing effects of her son s diagnosis..

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  • Title: Cystic Fibrosis - Your Genes, Your Health - DNA Learning Center - Cold Spring Harbor Laboratory
    Descriptive info: All the characteristics of cystic fibrosis from the lung infections, to the digestive difficulties, to the salty skin arise from a mutation in a single gene on chromosome 7.. This gene contains instructions for building a protein called the cystic fibrosis transmembrane conductance regulator.. That's quite a mouthful, so we'll just call it CFTR for short.. When there is no mutation in the gene, the instructions produce a CFTR that sits in the membrane of certain cells and controls the passage of chloride ions in and out of the cell.. When the gene is mutated, as it is in people with CF, the faulty instructions produce a CFTR that doesn't work, and chloride ions can not pass through the membrane.. In some cases, CFTR doesn't work because it won't open, as shown below.. But in 70 to 80 percent of CF cases in the United States, CFTR doesn't work because it's completely missing from the membrane! This radical change in the membrane is caused by a very small change in the CFTR gene.. Only three letters of code out of the gene's total of 6100 have disappeared.. But without this triplet, the instructions for putting the amino acid phenylalanine in position 508 in CFTR are missing.. (Thus, the name of this mutation is delta-F508).. A shortened CFTR is made, but the cell's quality-control system sees this as an error as the protein prepares to travel from its birthplace (the endoplasmic reticulum) to the cell membrane.. Quality-control flags the protein for destruction.. A missing (or malfunctioning) CFTR has many different effects on the body.. In the sweat glands, the missing protein causes the production of saltier sweat.. Sweat production begins in the tangled end of the gland where cells secrete water into the gland's duct.. As the sweat rises toward the skin, cells lining the upper duct reabsorb sodium ( ) and chloride ( ) ions, and other molecules in the sweat.. When CFTR is missing, chloride ions are not reabsorbed.. The loss of CFTR also stops the reabsorption of sodium ions, and the sweat that leaves the body is five times saltier than normal.. The loss of so much salt alters the balance of ions in the blood and can lead to abnormal heart rhythms.. CFTR also shuttles chloride ions in other organs, including the pancreas, where it ultimately prevents digestive enzymes from reaching the intestine.. Cells in the pancreas produce digestive enzymes and secrete them into the pancreatic duct for export to the intestine.. The chloride-pumping actions of CFTR cause water to follow the chloride into the duct, where the watery slurry flows out of the duct and into the intestine carrying the enzymes.. When CFTR is missing, the chloride and water stay in the cells.. There is no slurry to carry the enzymes away, so the enzymes begin to digest the pancreas itself.. This leads to inflammation, and thick mucus plugs the duct.. The organ that suffers most from the missing CFTR, though, is the lung.. It is not exactly clear how the absence of CFTR leads to lung damage, but mucus in the lung becomes very thick.. The lung becomes prone to bacterial infection because this mucus can support bacterial growth.. The thick mucus is hard to clear so it builds up in the bronchioles and reduces the surface available for oxygen exchange.. At the same time, infections damage lung tissue when the body's own immune cells release enzymes to kill the bacteria.. The enzymes incidentally kill lung cells, so chronic infections seriously damage the lung.. The severity of symptoms in CF varies from person to person, but over 90% of people with CF have measurably saltier sweat than people without CF.. Doctors use the "sweat test" which measures the amount of salt in the sweat to diagnose most cases.. Sweat is collected from the forearm with the help of a weak electric current and a sweat-inducing chemical called pilocarpine.. An electrode filled with pilocarpine is placed on the inner forearm, while the other electrode is placed on the outer forearm.. Current runs for five minutes making the arm feel tingly or warm to deliver the pilocarpine under the skin.. Once the electrodes are removed and the arm rests for four minutes, a piece of filter paper soaks up the sweat where the pilocarpine-filled electrode was attached.. The filter paper is placed into a flask after 30 minutes of sweat collection, and the sweat is rinsed from the filter.. A machine called a digital chloridometer measures the concentration of chloride ions in the sample.. A reading above 60 mmol/liter indicates the person has CF.. In cases where the sweat test is inconclusive or impossible to administer (as in infants), genetic testing can diagnose the disorder.. Because there are over 900 mutations that can cause CF, geneticists begin testing by searching for the most common mutation  ...   gene, there is no chance any of your children will inherit cystic fibrosis.. (In this case, the father has CF and the mother doesn't carry the gene).. Cystic fibrosis is a recessive disorder.. That is, a person gets cystic fibrosis only when he or she inherits two copies of the mutated gene, one from each parent.. Children should be tested for cystic fibrosis if they have persistent diarrhea, smelly and greasy stool, frequent pneumonia, chronic coughing, salty skin, or poor growth.. Cystic fibrosis (CF) affects about 1 in 2,500 births in the U.. and it affects males and females equally.. About 5% of the U.. population are unaffected carriers of the disorder.. CF is most common in Caucasians (1 in 3,300) and some Native Americans (Pueblo: 1 in 4,000; Zuni: 1 in 1,500).. It is less common in Americans of Hispanic (1 in 8,000), African (1 in 15,000, and Asian (1 in 32,000) descent.. People with cystic fibrosis have saltier sweat than others, so, the simple and inexpensive "sweat test" that measures the amount of salt in a person's sweat, is used for diagnosis.. Carriers of the cystic fibrosis gene can be detected with DNA testing, but the test can only pick up 80 to 85 percent of carriers of northern European descent.. Cystic fibrosis occurs when a genetic mutation stops the production of a protein in cells of the lung, pancreas, and other organs.. The absence of the protein impairs the cell's ability to transport chloride ions into and out of the cell.. This sets up secondary conditions, including the thick mucus and bacterial infections in the lung.. Nutritional problems from the lack of digestive enzymes are usually solved with enzyme supplements.. Lung problems are treated, but not cured, with chest percussions or other methods of clearing mucus, drugs that help break up the mucus, and antibiotics.. When the lungs begin to fail, a lung transplant can extend life.. Early signs of CF: Chronic respiratory and digestive problems are frequently the first signs of CF.. Prognosis: With today s treatments, prognosis is steadily improving year by year.. The CF Lung: Mucus & Infection: Dr.. Clement Ren describes the reasons why the lungs become infected and produce thick mucus.. The CF Lung: Inflammation: Damage to the lung occurs not from the bacterial infection itself, but from the inflammation caused by the immune system s attack on the bacteria.. Variability of CF: Dr.. Ren discusses the wide range of symptoms in CF and the varying severity from person to person.. Treatments: Present and Future: The mainstays of CF treatment include moving mucus out of the lungs and using antibiotics to control infection.. Care at CF Centers: Frequent check-ups at CF centers make sure the child is eating well and the lungs are functioning well.. Course of Bacterial Infections: The bacteria that infect the people with CF change as the person ages.. B.. cepacia: Though infection with this bacteria is not very common, it is much more aggressive than more common bacterial infections.. Lung Transplant: A transplant is an option after the lungs have become badly damaged.. As CF Population Ages: With more and more people with CF living into the middle age, diabetes and osteoporosis become additional problems.. Can people with CF have kids? Hundreds of women with CF in the United States have had children, but men are usually infertile and need in-vitro services.. CF and Ethnicity: Some ethnic groups have higher incidences of CF, but no one really knows why.. How is cystic fibrosis treated? What is it like to have cystic fibrosis? Feelings at Diagnosis: Getting updated information can help lessen the devastating feelings that come after diagnosis.. Treating a 2-year-old: The challenges of treating a 2-year-old with CF.. Daily Treatments: Fitting vest sessions or chest percussions into the daily routine.. Struggling with Weight: Supplements can help children with CF gain needed pounds but they re not always interesting to eat.. Doctor Visits: How many times the child need to see the CF doctors and what goes on during visits.. Telling Child about CF: What does a 6-year-old with CF need to know about her disorder.. Physical Activity: CF doesn t have to limit the child s physical activities, but the child should control his or her level of participation.. Child s Feelings: Helping a child with CF deal with the attention of other children and feelings of unfairness.. Siblings: Parents try to share their attention equally among all children.. School Interaction: Interacting with the child s class at the beginning of the school year can remove the stigma of being different and alert the teacher to the child s specific needs.. Having More Children: Issues the Sneddons Faced when they considered having another child.. Support Groups: Through support groups organized by the Cystic Fibrosis Foundation, you can meet other people with CF or other parents..

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