Prader-Willi syndrome

Prader-Willi syndrome is a rare genetic disorder. It is the most common cause of obesity caused by a genetic syndrome.

Clinical presentation

Prader-Willi syndrome is primarily characterized by:

• neonatal hypotonia

• sexual infancy: hypogonadism

• obesity

  • morbid obesity resulting from hyperphagia is amplified by decreased energy expenditure and reduced physical activity

  • hyperphagia has often been proven refractory to all psychopharmacological interventions

• intellectual disability

• short stature

Pathology

Genetics

Prader-Willi syndrome results from a mutation (deletion or partial deletion) in the molecular composition of a critical region of chromosome 15q11.2-13.

Radiographic features

Reported radiographically detectable features in childhood include ²:

• abnormalities of the calvarium and sella turcica

• small hands and feet with thin cortices and over-tubulated bones, and unequal extremities

• coxa valga

• scoliosis

• advanced dental caries

Sometimes later consequences such as early degenerative changes (non-specific) from morbid obesity may be seen.

Differential diagnosis

• fragile X syndrome: a very similar condition (referred to as Prader-Willi phenotype) may also be encountered ⁶

See also

• Angelman syndrome