Clinical Utility and Performance of Methylation-Specific Triplet-Primed PCR for Fragile X Syndrome Diagnosis

Fragile X syndrome (FXS) is the most common cause of intellectual disability. It is usually caused by the expansion of the CGG trinucleotide repeat (>200 repeats) in FMR1, resulting in DNA hypermethylation and gene silencing. Conventional FXS diagnosis is based on a combination of PCR and Southern blot (SB) analysis, which is technically challenging and labor-intensive. Methylation-specific triplet repeat-primed PCR (msTP-PCR) has been proposed to overcome these limitations in detecting FMR1 expansion and methylation status.