Williams 'syndrome is an autosomal dominant disorder characterized by all of the following features, except:

Ans. C. Subvalvular aortic stenosisWilliam's syndrome or Idiopathic hypercalcemia of infancy is an autosomal dominant disorder characterized by multiple congenital developmental defects, including supravalvular aortic stenosis, mental retardation, and an elfin facies, in association with hypercalcemia due to abnormal sensitivity to vitamin D.