Fragile+X+Syndrome

= **Fragile X Syndrome** = Fragile X syndrome is a genetic condition involving changes in part of the X chromosome. It is the most common form of inherited intellectual disability (mental retardation) in boys. **Etiology** Fragile X syndrome is caused by a change in a gene called FMR1. **Type of gene mutation** A small part of the gene code is repeated on a fragile area of the X chromosome. The more repeats, the more likely there is to be a problem. **Epidemiology** The FMR1 gene makes a protein needed for your brain to grow properly. A defect in the gene makes your body produce too little of the protein, or none at all. **Type of gene relationship** Boys and girls can both be affected, but because boys have only one X chromosome, a single fragile X is likely to affect them more severely. You can have fragile X syndrome even if your parents do not have it. A family history of fragile X syndrome, developmental problems, or intellectual disability may not be present. **Symptoms** Behavior problems associated with fragile X syndrome include: Physical signs may include: Some of these problems are present at birth, while others may not develop until after puberty. Family members who have fewer repeats in the FMR1 gene may not have mental retardation, but may have other problems. Women with less severe changes may have premature menopause or difficulty becoming pregnant. Both men and women may have problems with tremors and poor coordination. **Diagnosis** There are very few outward signs of Fragile X syndrome in babies. Some signs may include: In females, excess shyness may be the only sign of the disorder. Genetic testing can diagnose this disease. **Treatment** There is no specific treatment for Fragile X syndrome. Instead, training and education have been developed to help affected children function at as high a level as possible. **Prognosis** How well the patient does depends on the amount of intellectual disability (mental retardation). **Prevention** Genetic counseling may be helpful if you have a family history of this syndrome and are planning to become pregnant. **References**
 * Delay in crawling, walking, or twisting
 * Hand clapping or hand biting
 * Hyperactive or impulsive behavior
 * Mental retardation
 * Speech and language delay
 * Tendency to avoid eye contact
 * Flat feet
 * Flexible joints and low muscle tone
 * Large body size
 * Large forehead or ears with a prominent jaw
 * Long face
 * Soft skin
 * Large head circumference in babies
 * Mental retardation
 * Large testicles after the start of puberty
 * Subtle differences in face features
 * 1) Shapiro BK, Batshaw ML. Intellectual disability. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. //Nelson Textbook of Pediatrics//. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 33.
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