Test Details: Prader–Willi syndrome (PWS) is a genetic disorder caused by a loss of function of specific genes on chromosome 15 of the SNRPN gene. The disease is characterized by weak muscle tone , feeding difficulties, poor growth, and delayed development. This MS PCR-based assay evaluates the methylation status of the CpG island of the SNRPN gene and allows for rapid molecular diagnosis of Prader Willi Syndrome.MSPCR can be used to detect all presently testable causes of PWS (deletion, uniparental disomy, and imprinting mutation) in an efficient first step for stepwise diagnostic testing.