Prader-Willi syndrome

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 16 Mar 2025

Last updated: 20 Jun 2023

Prader-Willi syndrome (PWS; also known as Prader-Labhart-Willi syndrome) is a rare, complex, multisystem, neurological disorder caused by loss of paternally expressed genes on chromosome 15q11-q13.

Diagnosis is by identification of characteristic features with confirmation by genetic testing. Signs and symptoms may be extensive and wide-ranging; in general, however, consider genetic testing in an infant or young child with hypotonia, difficulty feeding, and/or hypogonadism. Depending on the age of the patient, other presenting features may include weight gain, hyperphagia, developmental delay, cognitive disability, sleep abnormalities, characteristic behaviours, and psychiatric disorders.

PWS presents less commonly in adolescence or early adulthood, with features including new-onset type 2 diabetes, constant hunger and food-seeking behaviours, short stature, obesity, learning difficulties, speech articulation problems, and autistic spectrum behaviours.

Features of acute illness may be subtle or atypical.

Management throughout the patient's life requires a multidisciplinary approach.

Patients with PWS have a shorter life expectancy than the general population, mainly due to complications of hyperphagia and obesity. However, with effective weight control management, patients with PWS may live into their seventh decade.

Definition

PWS (also known as Prader-Labhart-Willi syndrome) is a rare, genetically inherited complex neurological disorder caused by absence of expression of paternally inherited imprinted genes on chromosome 15q11-q13.[1][2] The syndrome typically occurs due to one of three genetic mechanisms: paternal deletion of involved genes, maternal uniparental disomy, or imprinting centre defects.[2][3] PWS is the most common known genetic cause of life-threatening obesity in humans.[4] Patients with PWS have a shorter life expectancy than the general population, which is mainly due to complications of hyperphagia and obesity.[5][6][7][8][9][10]