Prader-Willi syndrome (PWS) is an imprinting neurodevelopmental disorder resulting from loss of function of
paternal PWS critical genomic region on chromosome 15q11-q13. The clinical course in PWS is characterized by
neonatal hypotonia with feeding difficulties and failure to thrive. This is followed by onset of hyperphagia leading to
obesity. Patients with PWS have several neurobehavioral and psychiatric features including learning disability, autism
spectrum disorder, temper tantrums, repetitive behaviors, skin picking, affective disorders and psychosis.
In this review, we focus on genotype–phenotype correlations in PWS. We also describe the current protocol for genetic
testing to establish the diagnosis, the differential diagnosis of PWS, and the neurobehavioral and psychiatric
manifestations and their management.