$Unique_ID{BRK03752} $Pretitle{} $Title{Fragile X Syndrome} $Subject{Fragile X Syndrome X-linked Mental Retardation and Macroorchidism Marker X Syndrome Fraxa Martin-Bell Syndrome Repenning Syndrome Autism} $Volume{} $Log{} Copyright (C) 1988, 1989, 1990, 1991 National Organization for Rare Disorders, Inc. 586: Fragile X Syndrome ** IMPORTANT ** It is possible that the main title of the article (Fragile X Syndrome) is not the name you expected. Please check the SYNONYM listing to find the alternate names and disorder subdivisions covered by this article. Synonyms X-linked Mental Retardation and Macroorchidism Marker X Syndrome Fraxa Martin-Bell Syndrome Information on the following diseases can be found in the Related Disorders section of this report: Repenning Syndrome Autism General Discussion ** REMINDER ** The information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Fragile X Syndrome is a defect of the X chromosome which causes mild mental retardation. The disorder occurs more frequently and severely among males than females. This condition is the leading known familial cause of mental retardation in the U.S. Language delays, behavioral problems, autism or autistic-like behavior (including poor eye contact and hand-flapping), enlarged external genitalia (macroorchidism), large or prominent ears, hyperactivity, delayed motor development and/or poor sensory skills are among the wide range of symptoms associated with this disorder. Symptoms Fragile X Syndrome is characterized by connective tissue abnormalities such as joints which may be extended beyond normal limits (hyperextensible) and heart problems including mitral valve prolapse. Flat feet, large external genitalia (macroorchidism), large ears, and/or frequent ear infections (otitis media) also occur. Additionally, low muscle tone, a long narrow face, high arched palate, dental problems and an inability of the eyes to look in the same direction (strabismus) are common characteristics. Delayed motor development, hyperactivity, behavior problems, toe walking, and/or occasional seizures can also occur in some patients. Autism (a neurological behavior disorder) or autistic like behavior may include poor eye contact, hand flapping, and/or self-stimulating behaviors. (For more information about Autism, please choose "Autism" as your search term in the Rare Disease Database.) Poor sensory skills and mathematical ability are sometimes found in conjunction with good reading skills. Speech and language problems can include automatic repetition of words or phrases (echolalia), inability to mentally move from one idea to another (perseveration), poor language content, and/or dropping of letters or syllables when speaking (cluttering). The I.Q. of people with this disorder is generally lower than normal, although some people may have average intelligence. Causes Fragile X Syndrome tends to affect babies born to women later in life, usually past the age of 35. The condition results from a breakdown of certain areas on the X chromosome. Males have only one X chromosome while females have two. Therefore, when an X chromosome in a female is affected by this syndrome, the normal X chromosome can compensate for the defect, while males tend to have the more severe form of the disorder. In 1991 scientists discovered the gene on the X chromosome that results in Fragile X Syndrome. Researchers are hopeful that this will soon lead to genetic testing for the defect. Affected Population Fragile X Syndrome occurs with more frequency and severity among males than females. In 1986, scientists estimated that one in 981 males and one in 677 females have the fragile X Chromosome. Some of these people do not have symptoms, and many are only mildly mentally retarded. Related Disorders Symptoms of the following disorders can be similar to those of Fragile X Syndrome. Comparisons may be useful for a differential diagnosis: Renpenning Syndrome is a form of inherited X-linked mental retardation due to the presence of the genetic defect at a different site than that of Fragile X Syndrome (marXq28). This disorder occurs more frequently in males, although some females may also be affected. The following disorder may be associated with Fragile X Syndrome as a secondary characteristic. It is not necessary for a differential diagnosis: Autism is a lifelong neurological disorder characterized by onset before thirty months of age, retarded development of communication and language and lack of normal response to people. About seventy-five percent of Autistic children have lower than normal IQ's. Occasionally, an Autistic child shows distinct and unusual skills in music, mathematics, or in using spatial concepts. Autistic people live a normal life span. The prognosis for normal adaptation appears to vary with the level of functioning, intelligence and the educational methods applied. About 5 in 10,000 children have the fully expressed syndrome; 15 in 10,000 children show 2 or more of the main characteristics of autism. Boys are affected four times more frequently than girls. (For more information on Autism, please choose "Autism" as your search term in the Rare Disease Database.) Therapies: Standard Treatment of Fragile X Syndrome includes special education, speech, occupational, and sensory integration training, and behavior modification programs. Genetic counseling will be of benefit for families. Other treatment is symptomatic and supportive. Surgical correction of heart defects may sometimes be necessary. Therapies: Investigational Folic acid has been found to improve hyperactivity and attention deficits in some pre-adolescent males with Fragile X Syndrome. However, further study of this treatment is warranted to determine long-term benefits and possible side effects. Families with children who have the Fragile X chromosome are asked to contact Valerie Simon, Michael Reiss, M.D., and Lisa Freund, Ph.D. at the address below to participate in clinical research. Female children are especially needed. Valerie Simon, Michael Reiss, M.D., and Lisa Freund, Ph.D. The Kennedy Institute Behavioral Genetics Unit, Room 103 707 North Broadway Ave. Baltimore, MD 21205 (301) 550-9321 or (301) 550-9313 (collect) This disease entry is based upon medical information available through June 1991. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Fragile X Syndrome, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 Fragile X Foundation P.O. Box 300233 Denver, CO 80220 Fragile X Association of Michigan 1786 Edinborough Dr. Rochester Hills, MI 48064 (313) 373-3043 Fragile X Syndrome Support Group P.O. Box 3177 Camden, NJ 08181 Institute for Basic Research in Developmental Disabilities 1050 Forest Hill Road Staten Island, NY 10314 (718) 494-0600 NIH/National Institute of Child Health & Human Development (NICHHD) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5133 For Genetic Information and genetic counseling referrals: March of Dimes Birth Defects Foundation 1275 Mamaroneck Avenue White Plains, NY 10605 (914) 428-7100 Alliance of Genetic Support Groups 35 Wisconsin Circle, Suite 440 Chevy Chase, MD 20815 (800) 336-GENE (301) 652-5553 References GENETICS AND EXPRESSION OF THE FRAGILE X SYNDROME: W.T. Brown, et al.; Ups J Med Sci [Suppl] (1986, issue 44). Pp. 137-154. FOLIC ACID AS AN ADJUNCT IN THE TREATMENT OF CHILDREN WITH THE AUTISM FRAGILE-X SYNDROME (AFRAX): C. Gillberg, et al.; Dev Med Child Neurol (October 1986, issue 28(5) ). Pp. 624-627. MENDELIAN INHERITANCE IN MAN, 7th ed.: Victor A. McKusick; Johns Hopkins University Press, 1986. Pp. 1418-1421.