21. SAPL Catalog - Database Login 0www.nlm.nih.gov.sapl.sat.lib.tx.us/ medlineplus/ency/article/001668.htm - Similar pages Characteristics of fragile x syndrome - Fragilex.orgfragile x syndrome affects individuals in a wide variety of ways. Some individuals experience significant challenges because of the effects of fragile X, http://0-www.nlm.nih.gov.sapl.sat.lib.tx.us/medlineplus/ency/article/001668.htm

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22. Diagnosis And Management Of Fragile X Syndrome - July 1, 2005 - American Family fragile x syndrome is caused by an expansion mutation in the Fragile X mental retardation 1 (FMR1) gene located on the X chromosome. http://www.aafp.org/afp/20050701/111.html

Advanced Search AAFP Home Page Journals Vol. 72/No. 1 (July 1, 2005) Diagnosis and Management of Fragile X Syndrome DANIEL J. WATTENDORF, MAJ, MC, USAF, and MAXIMILIAN MUENKE, M.D., National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland This article exemplifies the AAFP 2005 Annual Clinical Focus on the legal, social, clinical, and ethical issues of medical genomics. See editorial on page 33 A glossary of genomics terms is available online A PDF version of this document is available. Download PDF now (3 pages /162 KB). F ragile X syndrome is caused by an expansion mutation in the Fragile X mental retardation 1 gene located on the X chromosome. It characteristically leads to some degree of mental retardation. The phenotype is subtle, with minor dysmorphic features and developmental delay during childhood. Characteristic features during adolescence are an elongated face, prominent jaw, large ears, macro-orchidism, and a range of behavioral anomalies and cognitive deficits (Figure 1).

23. Fragile X fragile x syndrome is the most common cause of inherited intellectual disability (mental People affected by fragile x syndrome are generally healthy. http://www.fragilex.org.au/

Fragile X Association of Australia Home Contact us at 1300 FXINFO Incorporating the NSW Parents Support Group Fragile X Syndrome - An Introduction What is Fragile X Syndrome? Fragile X syndrome is the most common cause of inherited intellectual disability (mental retardation). It is a disabling genetic condition which results in serious problems with learning and behaviour. Fragile X is found worldwide, in all ethnic groups and throughout society. Every week in Australia one child is born who is fully affected and twelve children are born who are carriers.* All males who carry the mutation will pass it to their daughters. And females have a 50% chance of passing the condition to their children. There is currently no cure for Fragile X but special therapies, methods of teaching and medication all provide real benefit to people with the syndrome and help them perform the best they can. *(Average based on International statistics indicate that 1 in 3600 males and 1 in 4000-6000 females are affected, 1 in 260 females and 1 in 800 males are carriers) Intellectual Characteristics Developmental delays are the most significant characteristic of those with fragile X. The range of learning problems is wide. Some are affected in fairly small ways, while at the other end of the scale, especially with males, there can be severe intellectual disabilities. Most affected males fall somewhere in the middle. Learning disabilities are often accompanied by delays in speech and communication skills. There can also be delays in both gross motor (such as sitting and walking) and fine motor (such as holding a pencil) skills. In general, females are not as delayed as males.

24. Fragile X A boy with fragile x syndrome. Note the prominent and elongated ears and This diagram displays fragile x syndrome. This occurs in about 1 in 1500 males. http://medgen.genetics.utah.edu/photographs/pages/fragile_x.htm

Fragile X Syndrome view 110KB version view 8KB version A boy with fragile X syndrome. Note the prominent and elongated ears and long face. Children from different ethnic groups have similar characteristics. This picture shows a Caucasian boy. view 1378 KB version view 5KB version This picture is of an Asian boy with fragile X syndrome. view 1864 KB version view 13 KB version This picture is of an Hispanic boy with fragile X syndrome. This diagram displays fragile X syndrome. This occurs in about 1 in 1500 males. Affected female carriers are typically normal. Most of the affected males have mental retardation, and their testes are larger than normal. Examinations Photographs Movies Links ... noJava Home

25. Facts About Fragile X Syndrome Information on fragile x syndrome including diagnosis, treatment, research, language and parent resources. http://www.childdevelopmentinfo.com/disorders/facts_about_fragile_x_syndrome.htm

Keeping Parents Informed Search our site: Find help for: Select A Topic ADD/ADHD Anxiety Aspergers Autism Bedwetting Behavior Problems Bipolar Disorder Depression Dyslexia Fears Homework OCD Reading School Problems Shyness Sibling Rivalry Sleep Problems Tourettes FREE Monthly Newsletter: Home Development Parenting Psychology ... [Parent Mart] Facts About Fragile X Syndrome Fragile X syndrome is the most common genetically-inherited form of mental retardation currently known. In addition to intellectual disability, some individuals with Fragile X display common physical traits and characteristic facial features, such as prominent ears. Children with Fragile X often appear normal in infancy but develop typical physical characteristics during their lifetime. Mental impairment may range from mild learning disability and hyperactivity to severe mental retardation and autism. This genetic syndrome is caused by a defect on the X chromosome. Because of scientific advances, improvements in genetic testing, and increased awareness, the number of children diagnosed with Fragile X has increased significantly over the last decade. Inheritance Testing for Fragile X Carrier A simple test is now available that can determine if a woman is carrier of the Fragile X gene. A drop of blood can be taken from the woman's finger and analyzed quickly and inexpensively. If a woman who is found to be a carrier is pregnant, she can arrange for testing of the fetus, as described below. For a woman with a family history of retardation, testing before pregnancy will help determine if she is at risk.

26. Fragile X Syndrome: Gene Fix? fragile x syndrome, linked to autism, may be eased by targeting a gene that makes the protein mGluR5, experts note in the journal Neuron. http://www.webmd.com/brain/news/20071219/fragile-x-syndrome-gene-fix

var s_furl = "/brain/news/20071219/fragile-x-syndrome-gene-fix"; var image_server_url = "http://img.webmd.com/dtmcms/live"; var priTopId = "1628"; var secTopId = ""; document.write(wmd_today); Bookmark This Page Site Map Sign up for WebMD Newsletters WebMD Home ... Drug News document.write(''); Women's Health Home Balance Fitness Parenting ... Pregnancy document.write(''); Men's Health Home Balance Fitness Parenting document.write(''); Children's Health Home Fitness Parenting Pregnancy ... WebMD Home Email a Friend Print Article Font Size A A A Fragile X Syndrome: Gene Fix? Tweaking a Certain Gene Eases Fragile X Symptoms in Lab Tests on Mice By Miranda Hitti WebMD Medical News Reviewed by Louise Chang, MD Dec. 19, 2007 Scientists may have found a genetic key to treating fragile X syndrome. Fragile X syndrome is the most common form of inherited mental retardation and is associated with autism "These findings have major therapeutic implications for fragile X syndrome and autism," the researchers write in tomorrow's edition of Neuron Such therapies aren't ready for use in people yet.

27. BBC - Health - Conditions - Fragile X Syndrome The causes and symptoms of fragile x syndrome. fragile x syndrome (or MartinBell syndrome) is the most common inherited cause of learning disability. http://www.bbc.co.uk/health/conditions/fragilex1.shtml

@import '/includes/tbenh.css'; Home TV Radio Talk ... A-Z Index 24 January 2008 Accessibility help Text only BBC Homepage Lifestyle ... Contact Us Like this page? Send it to a friend! Fragile X syndrome Dr Trisha Macnair Fragile X syndrome (or Martin-Bell syndrome) is the most common inherited cause of learning disability. In this article What causes it? What are the symptoms? Who's affected? How is it diagnosed? ... Advice and support What causes it? In fragile X, one of the genes on the X chromosome is faulty. A constriction can be detected near the tip of the X chromosome, which makes it fragile and susceptible to breakage. Boys are usually more severely affected by the syndrome, as they have only one X chromosome. Girls have a second X chromosome, which can be used instead of the faulty one, and may have only mild disabilities. They may also be silent carriers of the condition. What are the symptoms? The main problem in fragile X is mental impairment. This may range from a normal IQ to severe learning disabilities. Other symptoms include hyperactivity, attention deficit disorder, emotional and behavioural problems, anxiety and mood swings. There may also be characteristic facial features, such as a long face and large ears. Other physical features include flat feet and hyperextensible joints.

28. Genome.gov | Learning About Fragile X Syndrome fragile x syndrome is the most common form of inherited mental retardation in males and is also a significant cause of mental retardation in females. http://www.genome.gov/19518828

Home About NHGRI Newsroom Staff ... Specific Genetic Disorders Learning About Fragile X Syndrome Learning About Fragile X Syndrome What is fragile X syndrome? What are the symptoms of fragile X syndrome? What does it mean to have a fragile X premutation? How is fragile X syndrome diagnosed? ... Additional Resources for Fragile X Syndrome What is fragile X syndrome? Fragile X syndrome is the most common form of inherited mental retardation in males and is also a significant cause of mental retardation in females. It affects about 1 in 4,000 males and 1 in 8,000 females and occurs in all racial and ethnic groups. Nearly all cases of fragile X syndrome are caused by an alteration (mutation) in the FMR1 gene where a DNA segment, known as the CGG triplet repeat, is expanded. Normally, this DNA segment is repeated from 5 to about 40 times. In people with fragile X syndrome, however, the CGG segment is repeated more than 200 times. The abnormally expanded CGG segment inactivates (silences) the FMR1 gene, which prevents the gene from producing a protein called fragile X mental retardation protein. Loss of this protein leads to the signs and symptoms of fragile X syndrome. Both boys and girls can be affected, but because boys have only one X chromosome, a single fragile X is likely to affect them more severely. Top of page What are the symptoms of fragile X syndrome?

29. Fragile X Syndrome Corrected In Mice Discovery may lead to treatments for the genetic disease, a leading cause of mental retardation. http://health.usnews.com/usnews/health/healthday/071219/fragile-x-syndrome-corre

@import url(/usnews/v3/css/global.css); @import url(/usnews/v3/css/article.css); @import url(/usnews/v3/css/health.css); @import url(/usnews/v3/css/article-print.css); dblclick('leaderboardA'); dblclick('badgeA'); Thursday, January 24, 2008 Subscribe Contact Us Search U.S. News Health Education Opinion Science ... Rankings Health Article Index Subscribe USN Current Issue Home Health Print E-mail ... Reddit Fragile X Syndrome Corrected in Mice Discovery may lead to treatments for the genetic disease, a leading cause of mental retardation By Steven Reinberg Posted 12/19/07 WEDNESDAY, Dec. 19 (HealthDay News) By targeting one gene, scientists have been able to correct many of the abnormalities associated with fragile X syndrome, the most common inherited form of childhood retardation. Related News Join a Discussion More from Health Fragile X syndrome is caused by loss of the gene for "fragile X mental retardation protein" (FMRP). It affects about 100,000 people in the United States and is also a leading known genetic cause of autism. There is currently no treatment or therapy for fragile X syndrome. Symptoms include mental retardation, epilepsy, and abnormal body growth.

30. Neuron -- Dölen Et Al. fragile x syndrome (FXS) is the most common form of heritable mental retardation and the leading identified cause of autism. http://www.neuron.org/content/article/abstract?uid=PIIS0896627307009646

31. What Is Fragile X? fragile x syndrome is the leading inherited cause of developmental disabilities and mental impairment worldwide. It affects 1 in 2000 males and 1 in 4000 http://www.fraxsocal.org/

For September 28th Conference Brochure and Registration Form, click on EXCEPTIONAL STRATEGIES for SUCCESS below. FraxSoCal presents Exceptional Strategies for Success with Fragile X Syndrome An educational conference about Fragile X featuring Marcia L. Braden, PhD and Diane Simon Smith, MFT Friday, September 28, 2007 - 8am to 4:30pm California Senate and Assembly declare APRIL 18th of each year as CALIFORNIA FRAGILE X AWARENESS DAY U.S. House of Representatives DECLARES OCTOBER 05, 2002 AS NATIONAL FRAGILE X RESEARCH DAY (click on 4 links above to view Information, Resolutions or Registration) What is Fragile X syndrome? (for brochure, click here) Fragile X syndrome is the most common inherited cause of mental impairment, affecting approximately 1 in 3,600 males and 1 in 4,000 to 6,000 females with the full mutation worldwide. It is estimated that 1 in 250 females and 1 in 700 males are carriers of the premutation. It is second only to Down Syndrome as a cause of mental retardation. Both males and females may be affected by a wide variety of symptoms. Fragile X syndrome appears in children of all ethnic, racial and socio-economic backgrounds.

32. Fragile X Syndrome: Fundamental Brain Defect And Probable Drug Target Identified Scientists have discovered how the gene mutation responsible for fragile x syndrome the most common inherited form of mental retardation alters the http://www.sciencedaily.com/releases/2007/09/070917173149.htm

Science News Share Blog Cite Print Email Bookmark Fragile X Syndrome: Fundamental Brain Defect And Probable Drug Target Identified ScienceDaily (Sep. 18, 2007) See also: Down's Syndrome Birth Defects Gene Therapy Autism ... Sex linkage The research was led by Stephen T. Warren, PhD, Timmie professor and chair of human genetics in Emory University School of Medicine, and Gary J. Bassell, PhD, Emory professor of cell biology. It will be reported in the Proceedings of the National Academy of Sciences the week of Sept. 17. Lead author is Emory genetics postdoctoral fellow Mika Nakamoto. "We have now explained the fundamental defect in the brain in fragile X syndrome and, most importantly, found that we can correct this problem in the laboratory," says Dr. Warren. "This is quite exciting, progressing from the identification of the gene in 1991 to now believing we will be able to treat a previously untreatable condition. Our next steps will be to continue screening and identifying the best drugs to try and correct the deficiencies that result from fragile X syndrome." Fragile X syndrome is caused by a mutation in the FMR1 gene on the X chromosome. A region of the mutated FMR1 gene repeats a trinucleotide sequence of DNA basesCGGbetween 200 and 1,000 times, rather than the normal 6 to 55 repeats in normal individuals. The abnormal trinucleotide repeats cause the absence of the FMR protein normally produced by the gene.

33. Fragile X Retardation Syndrome Corrected In Mice Researchers working with mice have significantly alleviated a wide range of abnormalities due to fragile x syndrome by altering only a single gene, http://www.eurekalert.org/pub_releases/2007-12/cp-fxr121407.php

Public release date: 19-Dec-2007 E-mail Article Contact: Cathleen Genova cgenova@cell.com Cell Press Fragile X retardation syndrome corrected in mice Researchers working with mice have significantly alleviated a wide range of abnormalities due to fragile X syndrome by altering only a single gene, countering the effects of the fragile X mutation. They said their achievement offers the potential for treatment of the disorder, the most common form of inherited mental retardation and a leading identified genetic cause of autism. There is currently no treatment or therapy for fragile X syndrome, whose symptoms include mental retardation, epilepsy, and abnormal body growth. Mark Bear and colleagues reported their findings in an article in the December 20, 2007, issue of the journal Neuron, published by Cell Press. Fragile X syndrome is known to be caused by loss of the gene for “fragile X mental retardation protein” (FMRP), which is believed to act as a brake on protein synthesis in specific areas of brain circuitry. The authors’ idea was that loss of the “brake” would allow another protein that stimulates this process, called metabotropic glutamate receptor 5 (mGluR5), to function unchecked. In their experiments to test this idea, the researchers studied mice that produce many of the characteristic pathologies of fragile X in humans due to a loss of the FMRP gene. The critical test, though, was when they also created double mutant mice that lacked both the FMRP gene and had a 50% reduction in mGluR5. They chose only to reduce the activity of the metabotropic glutamate receptor gene, rather than eliminate it, in order to reflect what might be achieved using drug treatment for fragile X in humans.

34. Fragile X Syndrome Update fragile x syndrome (FXS) is the most common cause of inherited mental impairment. This impairment can range from learning disabilities to more severe http://www.geneticsandhealth.com/2007/08/19/fragile-x-syndrome-update/

b5media.com Advertise with us Enjoying this blog? Check out the rest of the Genetics and Health Subscribe to Genetics and Health Add Genetics and Health to del.icio.us Add Genetics and Health to Google Reader Fragile X syndrome update by Elaine on August 19th, 2007 Fragile X is a family of genetic conditions, which can impact individuals and families in various ways. These genetic conditions are related in that they are all caused by gene changes in the same gene, called the FMR1 gene. Fragile X associated tremor/ataxia syndrome (FXTAS) is a condition which affects balance, tremor and memory in some older male gene carriers. These age 50+ men exhibit Parkinsonian type symptoms and a marked reduction in memory and cognitive abilities. Fragile X associated  premature ovarian failure (POF) a problem with ovarian function which can lead to infertility and early menopause in some female gene carriers. http://www.neuron.org    Sofola et al and Jin et al Penny Share This Related Stories Genetic disorders that are written on our faces Partington Syndrome and Blog of the Week: Dream Mom MeCP2 Gene and Rett Syndrome POSTED IN: Genealogy and DNA General Genetics and Health Genetic Engineering Genetic Future ... Genetic Testing 4 opinions for Fragile X syndrome update Aug 21, 2007 at 10:58 pm

35. Health Supervision For Children With Fragile X Syndrome -- Committee On Genetics Automatic download Begin manual download. Downloading the PDF version of AAP Policy Committee on Genetics 98 (2) 297. (725K) http://aappolicy.aappublications.org/cgi/reprint/pediatrics;98/2/297

HOME HELP E-MAIL ALERTS SEARCH ... Email this article to a friend Similar articles found in: AAP Policy Online PubMed PubMed Citation Download to Citation Manager PDF Version Automatic download Begin manual download Downloading the PDF version of: AAP Policy Committee on Genetics 98 (2): 297. This file is in Adobe Acrobat (PDF) format . If you have not installed and configured the Adobe Acrobat Reader on your system, see Help with Printing for instructions. Having trouble reading a PDF? PDFs are designed to be printed out and read, but if you prefer to read them online, you may find it easier if you increase the view size to 125%. Having trouble saving a PDF? Many versions of the free Acrobat Reader do not allow Save. You must instead save the PDF from the AAP Policy Online page you downloaded it from. PC users: Right-click on the Download link and choose the option that says something like "Save Link As...". Mac users should hold the mouse button down on the link to get these same options. Having trouble printing a PDF?

36. Fragile X Syndrome fragile x syndrome is a genetic condition involving changes in the long arm of the X . It is characterized by mental retardation. http://adam.about.com/encyclopedia/001668sym.htm

zGCID=" test0" zGCID=" test0 test14" zJs=10 zJs=11 zJs=12 zJs=13 zc(5,'jsc',zJs,9999999,'') You are here: About Healthcare Center Healthcare Center Healthcare Center ... Help ENCYCLOPEDIA INDEX Injury Disease Nutrition Poison ... Z Fragile X syndrome Overview Symptoms Treatment Prevention Alternative Names: Martin-Bell syndrome; Marker X syndrome Symptoms: Family history of fragile X syndrome, especially a male relative Mental retardation Large testicles (macro-orchidism) Large size Tendency to avoid eye contact Hyperactive behavior Large forehead and/or ears with a prominent jaw Signs and tests: A specific genetic test (PCR) can now be performed to diagnose this disease. This test looks for an expanded mutation (called a triplet repeat) in the FRAXA gene. Formerly a specific type of chromosome analysis was done and this may still be available. There are very few outward signs of Fragile X syndrome in babies but one is a tendency to have large head circumference. Measurement of oversized testes in males can also suggest the diagnosis. An experienced geneticist may note subtle differences in facial characteristics. Mental retardation is the hallmark of this condition and, in females, this may be the only sign of the problem.

37. Fragile X Syndrome: Chromosomal And Genetic Abnormalities: Merck Manual Home Edi The symptoms of fragile x syndrome are caused by abnormalities in DNA on the X chromosome. Usually, affected boys inherit the condition from their mothers. http://www.merck.com/mmhe/sec23/ch266/ch266c.html

Search Recent Searches Index Sections A B ... view all sections In This Topic Fragile X Syndrome Back to Top Section Children's Health Issues Subject Chromosomal and Genetic Abnormalities Topics Introduction Down Syndrome Fragile X Syndrome Klinefelter Syndrome Long QT Syndrome Noonan Syndrome Triple X Syndrome ... XYY Syndrome Fragile X Syndrome drawAdBox(adPath, numberOfAds, false); Buy the Book Print This Topic Email This Topic Pronunciations autism mitral mitral valve mitral valve prolapse Fragile X syndrome is a genetic abnormality in an X chromosome that leads to delayed development and other symptoms. The symptoms of fragile X syndrome are caused by abnormalities in DNA on the X chromosome. Usually, affected boys inherit the condition from their mothers. Many children with the syndrome have normal intelligence. However, the syndrome is the most commonly diagnosed genetic cause of mental retardation besides Down syndrome. The severity of symptoms, including mental retardation, is worse in boys than in girls with the disorder. Symptoms, which are often subtle, include delayed development; large, protuberant ears; a prominent chin and forehead; and, in boys, large testes (most apparent after puberty). The joints may be abnormally flexible, and heart disease (mitral valve prolapse) may occur. Features of autism may develop. Women may experience menopause in their mid 30s. The presence of abnormal DNA on the fragile X chromosome can be detected by tests before or after birth. The greater the number of abnormal repetitions of DNA found, the more likely the child will have symptoms.

38. PA-06-429: Shared Neurobiology Of Fragile X Syndrome And Autism (R03) NIH Funding Opportunities and Notices in the NIH Guide for Grants and Contracts Shared Neurobiology of fragile x syndrome and Autism (R03) PA06-429. NIMH. http://grants.nih.gov/grants/guide/pa-files/PA-06-429.html

Part I Overview Information Department of Health and Human Services Participating Organizations National Institutes of Health (NIH) ( http://www.nih.gov Canadian Institutes of Health Research (CIHR), ( http://www.cihr-irsc.gc.ca/e/193.html Health Research Board, Ireland (HRB), ( http://www.hrb.ie/ FRAXA Research Foundation (FRAXA), ( http://www.fraxa.org Cure Autism Now (CAN), ( http://canfoundation.org/ National Alliance for Autism Research (NAAR), ( http://www.naar.org/ Autism Speaks ( http://www.autismspeaks.org/ Components of Participating Organizations National Institute of Mental Health (NIMH) ( http://www.nimh.nih.gov National Institute for Neurological Disorders and Stroke (NINDS), ( http://www.ninds.nih.gov/ http://www.nichd.nih.gov Institute of Neurosciences, Mental Health and Addiction (INMHA), ( http://www.cihr-irsc.gc.ca/e/8602.html Institute of Genetics (IG), ( http://www.cihr-irsc.gc.ca/e/13147.html Title: Shared Neurobiology of Fragile X Syndrome and Autism (R03) Announcement Type This is a reissue of PA-05-108 , which was previously released May 12, 2005, and is now divided into separate FOAs for R01, R21, and R03 funding mechanisms.

39. What Is Fragile X? - Fragile X Program - Clinical Services - Children's Hospital fragile x syndrome (FXS) is a hereditary condition that can cause Not everyone with fragile x syndrome will have all of the mentioned characteristics. http://www.childrenshospital.org/clinicalservices/Site2242/mainpageS2242P4.html

advanced search or find by letter: A-F G-L M-R S-Z Fragile X Program Fragile X Program What Is Fragile X? The Program Experience Meet the Team Frequently Asked Questions Resources ... Find Us Return to Genetics Home Clinical Services Fragile X Program What Is Fragile X? What Is Fragile X? Fragile X syndrome (FXS) is a hereditary condition that can cause learning and behavioral problems in both males and females. It is the most common known cause of mental impairment. The range of impairment seen in those with fragile X is very broad, including those with normal IQ and mild learning disabilities to mental retardation and autism. In addition, certain behavioral and emotional problems such as hyperactivity, social anxiety and mood disorders may be present. Characteristics of FXS Those with fragile X syndrome have certain physical, behavioral and intellectual characteristics seen in both males and females. Not everyone with fragile X syndrome will have all of the mentioned characteristics. Physical characteristics Males with fragile X often have the following: large ears a long and narrow face prominent foreheads and chins flat feet large testicles (macroorchidism) Females with fragile X may also show distinct physical characteristics, including:

40. MSRGSNet/Genetic Drift/Management Of Common Genetic Disorders fragile x syndrome is the most common cause of inherited mental retardation with fragile x syndrome is responsible for approximately 10% of all cases of http://mostgene.org/gd/gdvol16d.htm

Previous Section This Issue- Table of Contents Next Section Management of Common Genetic Disorders Vol. 16: Summer, 1998 Fragile X Syndrome Introduction Fragile X syndrome is the most common cause of inherited mental retardation with an incidence of approximately 1 in 2000 male, and 1 in 2500 female, live births. The carrier frequency in females is 1/259 and in males is 1/755. Fragile X syndrome is an X-linked disorder and occurs with equal frequency in all ethnic groups. Fragile X syndrome is responsible for approximately 10% of all cases of inherited mental retardation and 30% of cases of X-linked mental retardation. The gene responsible for fragile X syndrome is located on the X chromosome and is known as the Fragile X Mental Retardation 1 (FMR1) gene. Within the FMR1 gene is a specific region of CGG repeats. Individual with fewer than 40 repeats are not at risk to pass on fragile X syndrome to their offspring. Individuals with 55 to 200 repeats are said to carry the FMR1 premutation. Male individuals with more than 200 repeats have fragile X syndrome. Females with more than 200 repeats have a 50-70% risk to have a low or borderline IQ and a 30-50% chance to have a normal IQ. Approximately 60% of females with more than 200 repeats and a normal IQ have learning problems and emotional or behavioral difficulties. There are a few reports in the literature documenting fragile X syndrome due to deletions of the FMR1 gene, but the vast majority of cases are the result of expansion of the CGG triplet repeat within the FMR1 gene. Expansion occurs when the gene mutation is passed from the mother to the child.

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