PCR based diagnosis of fragile X syndrome

Abstract

Fragile X syndrome, a common cause of mental retardation in males and milder learning problems in females, is related to CGG trinucleotide repeat expansion in the FMR1 gene. Premutations are a cause of premature ovarian failure in females and adult-onset syndrome of ataxia, tremor, and cognitive decline (FXTAS) in males. Clinical testing for premutations can be achieved by PCR amplification of the CGG repeats in a denaturing buffer and size fractionation on an ethidium bromide-stained gel. Full mutations are detected by Southern blotting of the PCR products and probing with a CGG oligonucleotide.