Autism-World

Mutations in the FMR1??gene cause fragile X syndrome.FMR1 is a ??fragile area on the X chromosome.It repeats in the genetic code.Normally, this DNA segment is repeated from 5 to about 40 times.The more repeats, the more likely there is to be a problem.In people with fragile X syndrome, however, the CGG(the DNA segment) 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 or a shortage (deficiency) of this protein leads to the signs and symptoms of fragile X syndrome.

In a small percentage of cases, other types of mutations cause fragile X syndrome. These mutations delete part or all of the FMR1 gene or change one of the building blocks (amino acids) used to make the fragile X mental retardation protein. As a result, no protein is produced, or the protein is disabled because its size or shape is altered.

This entry was posted on Wednesday, March 21st, 2007 at 9:45 pm and is filed under Fragile X Syndrome.