Treatment of homozygous familial hypercholesterolaemia: an informative sibship.

In a family in which both parents had the heterozygous form of familial hypercholesterolaemia four of the children had the homozygous form. The three oldest homozygous children, two of whom did not receive any treatment and in one of whom treatment did not lower the plasma cholesterol concentration, developed xanthomas in early childhood and died aged 3, 9, and 10 years. The fourth homozygous child was treated with diet and drugs from the age of 1 and at the age of 15 had no xanthomas, no clinical evidence of heart disease, and a virtually normal coronary angiogram. His plasma cholesterol concentration was reduced by about 30% but remained considerably raised. It is concluded that treatment, if started before atherosclerosis develops, can delay the onset of atheroma and coronary heart disease even though normal plasma cholesterol concentrations are not achieved.