What are the features of Williams syndrome?
Williams syndrome is characterised by supravalvar aortic stenosis, elfin facies and hypercalcemia. Learning disability is often associated. Peripheral pulmonary stenosis is also an association.
In supravalvar aortic stenosis, the right upper limb blood pressure can be more than that in left upper limb causing anisopsphygmia, because the jet is directed towards the brachiocephalic artery. This is due to Coanda effect.