The genotype and phenotype correlation of Prader-Willi syndrome

Prader-Willi syndrome (PWS) is a multifaceted congenital disorder resulting from the absence of paternally imprinted genes on chromosome 15q11.2-q13.1. Its clinical features vary with age, initially presenting as severe hypotonia and feeding difficulties in infancy, followed by hyperphagia in early childhood, ultimately leading to significant obesity. According to the underlying mechanism, the PWSs are divided into three main types. The deletion type with only one maternal copy accounts for 65%-75% of patients and may be divided into subtypes I to IV. Maternal uniparental disomy (mUPD) has two maternal copies, accounting for 20%-30% of patients, and is divided into the isodisomy subtype and heterodisomy subtype. Imprinting defects account for less than 5% of patients and are divided into epimutation and imprinting center deletions. The genotype-phenotype correlation has recently been investigated. Differences in the frequency and severity of specific features among various genotypes, particularly between deletion and mUPD types, have been reported. Herein, we reviewed the current literature and evidence on the genotype-phenotype correlation in PWS, which may help us to understand the mechanism and reasonable management of PWS.