Familial Plasma Lecithin: Cholesterol Acyltransferase Deficiency Biochemical Study of a New Inborn Error of Metabolism

Abstract

Three adult sisters with a new inborn error in lipid metabolism have been studied. They had an almost complete lack of esterified cholesterol in plasma, and a high concentration of plasmafree cholesterol. The plasma concentrations of lecithin were high and of lysolecithin low. These abnormalities were found to be associated with an absence of plasma lecithin: cholesterol acyltransferase. No inhibitors of this enzyme could be demonstrated in the plasma of the patients. The small amounts of cholesterol esters found in the plasma of the patients were found to be formed during intestinal absorption of cholesterol. The two eldest patients had lipemic plasma. The fatty acid composition of the triglycerides were normal. Electrophoresis of the plasma lipoproteins revealed a pathological pattern: no α- and no pre- β-lipoproteins could be demonstrated. Immunoelectrophoresis also revealed an α-lipoprotein deficiency. The data obtained in the present study strongly suggest that the plasma cholesterol esterification reaction is the major pathway for the formation of plasma cholesterol esters.