Homozygous familial hypercholesterolemic patients in China.

Five homozygous patients with familial hypercholesterolemia (FH) are described. Their serum cholesterol levels were between 603 and 907 mg/dl, with an average of 714 mg/dl. The mean value of serum cholesterol levels of the obligate heterozygous parents was 270 mg/dl. In the patient group, 87% of the serum cholesterol was distributed in low density lipoprotein (LDL) and the mean LDL cholesterol level was about 8.4 times that in a control group. Phospholipids in HDL in the patient group were significantly lower than in the controls. Lipid assays of xanthoma tissues revealed that the major lipid was cholesterol and its esters. LDL receptor activity in fibroblasts from the homozygotes was markedly decreased. Two patients yielded less than 2% of normal receptor activity and were classified as receptor-negative. The other 3 revealed receptor activities greater than 2% but less than 25% of normal receptor activity and were classified as receptor-defective.