12th April 2024

Prader-Willi syndrome

This condition is caused by the loss of gene expression present on chromosome 15. It is mostly acquired spontaneously but can be passed down from the paternal genes of the mother. On examination, the patient would have a short stature, almond-shaped eyes with a thin upper vermilion and narrow nasal bridge. Patients affected by this condition have a trend of failure to thrive, which progressively reaches the opposite spectrum of obesity (in mid-adulthood) secondary to hyperphagia. As well as this, it causes hypotonia with reduced muscles and strength, leading to poor suck reflex and motor developmental delay. During childhood, speech is commonly affected, and behavioural conditions such as OCD or anxiety may be present. Sexual development is also affected, causing hypogonadism in males due to cryptorchidism and hypoplasia of external genitalia, and late menarche in females. Investigations and diagnosis involve DNA methylation testing. Many patients are GH deficient and administration of this hormone aids physical and cognitive development.