Fragile X Syndrome
Category : Articles
Fragile X Syndrome is an x-linked trait and the second most common identifiable cause of genetic mental retardation after Down syndrome (Wyndbrandt & Ludman, 2008). It is a very unpredictable and unpreventable disorder which not only touches those who suffer from it, but those around them as well. Its affect, is sometimes devastating. When analyzing Fragile X Syndrome it is crucial to examine its inheritance pattern, the genetic mutation which causes the disease, the signs and symptoms of the disorder.
Foremost, Fragile X Syndrome is caused by a break of weakness on the long arm of the X chromosome. It can be traced back to a mutation in a gene called the FMR-1 gene. With Fragile X, the FMR-1 gene is much bigger than normal where the CGG is repeated. The average number of repeats is 30 for a normal person. A carrier of fragile X will usually have 50-200 repeats. A person with Fragile X has 200 or more repeats. A person with Fragile X has a ???full mutation???. When there are so many repeats in the gene, methyl groups attach to the cytosine and turn the gene off. The gene then cannot produce any FMRP (Fragile X Mental Retardation Protein). If a person doesn??™t have the protein, they can develop mental impairment and other characteristics (Alanay, 2007).
Fragile X is estimated to occur in 1 in 1,200 males and 1 in 2,500 in females. It occurs in all racial, ethnic, and socioeconomic groups. It is the most common genetic disease and is the most commonly inherited cause of learning disabilities and mental retardation, accounting for approximately 40 percent of cases with X-linked mental retardation. A screening study in a U.S. public special education population suggests that approximately 1 in 400 males receiving special education services are affected the Fragile X syndrome (Crawford, 2001). Although the Fragile X Syndrome occurs in both male and females, females have usually milder symptoms.
Furthermore, when discussing Fragile X Syndrome, it becomes obvious that the signs and symptoms of this disease are important topics that must be looked into. The most important thing to realize is that this genetic disease usually manifests itself in the form of mental retardation. The classic phenotype of Fragile X Syndrome in males includes:
??? mental retardation, with an average IQ of 50 and a range of 25-90, with most under 70 (Alanay: 2007)
??? behavioral features similar to those seen in autism
??? characteristic facies including long narrow face with prominent chin, tall forehead, flat nasal bridge, and large pinnae (these features may be subtle)
??? flexible finger joints and flat feet
??? post pubertal macroorchidism
Females with Fragile X Syndrome generally have milder manifestations, although they may have:
??? some similar physical features, particularly large or prominent ears, flexible finger joints, and flat feet
??? learning problems in the majority
??? short attention span
??? moodiness, shyness, anxiety
??? mental retardation in 30%
Next, detection in the carrier is relatively new. However, in 1991, scientist discovered the gene FMR-1 that has led to the development of improved testing for both carriers of the syndrome and those affected. The testing is done by DNA and is a blood test which requires sending blood to a lab which specializes in DNA studies. The test is very accurate and can be used for prenatal diagnosis. In addition, fetal testing can be done through either amniocentesis or earlier in pregnancy through chronic villus sampling (Crawford, 2001).
Finally, at this time, there is no cure for fragile X syndrome. However, special education, speech and language therapy, occupational therapy and behavioral therapies are helpful in addressing many of the behavioral, and cognitive issues in fragile X syndrome. In addition, medical intervention including medications can be helpful for aggression, anxiety, hyperactivity and poor attention span. Because the impact of fragile X is so varied, it is important to do a careful evaluation of the individuals abilities and difficulties to tailor a treatment plan to address specific needs.
The outlook for children with fragile X syndrome is better when the disease is diagnosed early. Among people with a full fragile X mutation, about half of females and almost all males have lifelong mental retardation. People with fragile X syndrome usually have a normal lifespan (Crawford, 2001).
In conclusion, it becomes very apparent that Fragile X Syndrome is a very complicated and harsh genetic disorder that touches the lives of thousands of people. It is a disease than cannot be prevented or cured. Fragile X Syndrome is a very important genetic disorder which has, and will continue to have a terrible impact on society for as long as it exists. Through analyzing the Fragile X Syndrome gene and mutation, the protein and cell metabolism of this disease, the signs, symptoms, and phenotype of Fragile X Syndrome, the lifestyle, emotional effects, and view of society concerning this genetic disorder, and the diagnosis, treatment which deal with this Syndrome, it becomes very obvious that Fragile X Syndrome is a problem that needs to be solved.