William syndrome is caused by a deletion of genetic material on one copy of chromosome 7, resulting in the person only having a single copy of the genes on this deleted region (on the other chromosome 7). It usually the result of a random deletion around conception, rather than being inherited from an affected parent.
Features
- Broad forehead
- Starburst eyes (a star-like pattern on the iris)
- Flattened nasal bridge
- Long philtrum
- Wide mouth with widely spaced teeth
- Small chin
- Very sociable trusting personality
- Mild learning disability
TOM TIP: The distinctive features to remember with William syndrome are the very sociable personality, the starburst eyes and the wide mouth with a big smile. It is worth remembering the association with supravalvular aortic stenosis and hypercalcaemia, as these are unique features that are easy to test in exams.
Associated Conditions
- Supravalvular aortic stenosis (narrowing just above the aortic valve)
- Attention-deficit hyperactivity disorder
- Hypertension
- Hypercalcaemia
Management
Like many other genetic syndromes, there is no cure and management focuses on a multi-disciplinary team approach to managing individual problems and supporting the patient and family. Echocardiograms and blood pressure monitoring are important to assess for aortic stenosis and hypertension. A low calcium diet may be required to control hypercalcaemia, and they should avoid calcium and vitamin D supplements.
Last updated January 2020