Historically, screening and diagnostic techniques for FXS can include prenatal testing, specifically amniocentesis and chorionic villus sampling, recommended for families with a history of FXS or related symptoms, or postnatal testing such as polymerase chain reaction (PCR) combined with Southern blot analysis and triplet-primed PCR (TP-PCR) for identifying FMR1 gene mutations. The gene discussed is FMR1; the disease is fragile X syndrome.