Definition of Williams Syndrome
Williams syndrome: A genetic disorder characterized by mild mental retardation, unique personality characteristics, unusual facial features, and cardiovascular disease. The level of calcium tends to be high in blood (hypercalcemia) and urine (hypercalciuria).
Mental retardation is the rule and ranges from severe to mild. Personality features include overfriendliness, general anxiety, and attention deficit disorder. Facial features include narrow forehead, fullness about the eyes, short nose, flat midface, full lips, wide mouth, small jaw, and prominent earlobes. Supravalvar aortic stenosis (narrowing of the aorta just above the valve) is the most common and important cardiovascular abnormality.