Prader-Willi syndrome is a rare genetic disorder. It is the most common cause of obesity caused by a genetic syndrome.
Prader-Willi syndrome is primarily characterized by:
- neonatal hypotonia
- sexual infancy: hypogonadism
- 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
Prader-Willi syndrome is thought to result from an alteration (deletion or partial deletion) in the molecular composition of a critical region of chromosome 15 (q11-13).
A very similar condition (referred to as Prader-Willi phenotype) is also encountered as part of fragile X syndrome .
Reported radiographically detectable features in childhood include :
- abnormalities of the calvarium and sella turcica
- small hands and feet with thin cortices and over-tubulated bones, and unequal extremities
- coxa valga
- advanced dental caries
Sometimes later consequences such as early degenerative changes (non-specific) from morbid obesity may be seen.