Fragile X Syndrome is one of the most commonly inherited diseases caused by CGG trinucleotide repeat expansions in the promoter region of the fragile X mental retardation-1 (FMR1) gene. The AmplideX® FMR1 PCR reagents are the latest research tools for the detection of CGG repeats in the fragile X mental retardation (FMR1) gene. These reagents can detect full mutations up to at least 1300 CGG repeats, accurately size up to 200 CGG repeats, detect interrupting AGG sequences and resolve female zygosity. These reagents have been evaluated in a peer-reviewed publications and tested in dozens of laboratories in the US and abroad. Either PCR format can reduce the number of samples required for Southern blot analysis by as much as 50-fold.