Overview
Prader-Willi syndrome (PWS) describes a set of features seen due to genetic imprinting (where epigenetic marks are inherited from the parents, resulting in no expression of a gene) affecting genes on chromosome 15 at the 15q11-13 region.
Normally, a person inherits an imprinted (non-expressed) copy of genes associated with PWS and relies on the expression of the paternal copy. In PWS, the paternal copy is deleted, or two imprinted maternal copies are passed onto the offspring, resulting in no expression of these genes.
The opposite of this (maternal deletion or two paternal copies being inherited) leads to Angelman’s syndrome.
Epidemiology
- The prevalence of PWS is estimated to be up to 1 in 10,000 people
Presentation
- Hypotonia during infancy
- Short stature
- Learning difficulties
- Hypogonadism and infertility
- Excessive hunger and obesity
- Dysmorphic features (e.g. narrow face, almond-shaped eyes etc.)
