Prader-Willi syndrome (PWS; also known as Prader-Labhart-Willi syndrome) is a rare, complex, multisystem, neurologic 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 behaviors, 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 behaviors, short stature, obesity, learning difficulties, speech articulation problems, and autistic spectrum behaviors.
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.
PWS (also known as Prader-Labhart-Willi syndrome) is a rare, genetically inherited complex neurologic disorder caused by absence of expression of paternally inherited imprinted genes on chromosome 15q11-q13. The syndrome typically occurs due to one of three genetic mechanisms: paternal deletion of involved genes, maternal uniparental disomy, or imprinting center defects. PWS is the most common known genetic cause of life-threatening obesity in humans. Patients with PWS have a shorter life expectancy than the general population, which is mainly due to complications of hyperphagia and obesity.
History and exam
Key diagnostic factors
- central hypotonia
- poor suck
- weak cry
- feeding difficulties
- weight gain and hyperphagia
Other diagnostic factors
- developmental delay
- cognitive disability
- endocrine disorders
- sleep abnormalities
- behavioral abnormalities
- psychiatric disorders
- short stature
- small hands and feet
- ocular problems
- spinal deformities
- decreased fetal movements
- developmental dysplasia of the hip
- premature adrenarche
- older maternal age (>35 years)
- hydrocarbon exposure
- conception using assisted reproductive technology
- sibling with Prader-Willi syndrome (PWS)
1st investigations to order
- DNA methylation testing
Investigations to consider
- further genetic testing
with acute illness
without acute illness
- Spinal muscular atrophy
- Angelman syndrome
- Temple syndrome
- Guides for doctors: consensus documents
- Health supervision for children with Prader-Willi syndrome
Weight problems in adults: questions to ask your doctor
Weight problems in children: changing unhealthy habitsMore Patient leaflets
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