Description

Fragile X syndrome (FXS) is a rare genetic disease associated with mild to severe intellectual deficit that may be associated with behavioral disorders and characteristic physical features. FXS is caused by the transcriptional silencing of the FMR1 gene (Xq27.3) due to the progressive expansion and subsequent methylation of (CGG)n trinuleotide repeats in the 5′-untranslated region of the gene. These full mutations originate from unstable alleles called premutations (55-200 CGG repeats), also associated with other phenotypes, including a risk of primary ovarian insufficiency in women and the fragile X-associated tremor/ataxia syndrome (FXTAS). In some rare cases, FXS was shown to result from intragenic FMR1 point mutations or deletions.

External Information

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