Paradoxical Esterification of Plasma Cholesterol in Fish Eye Disease

Abstract

The activity of lecithin:cholesterol acyl transferase (LCAT), the enzyme which catalyses the esterification of human plasma cholesterol, has been measured by 2 independent methods in plasma from the 2 known living Swedish patients with fish eye disease. The enzyme activity was in both cases about 15% of that of normal plasma. Paradoxically, however, the percentage of plasma cholesterol which was esterified was almost normal in both patients. In addition, a normal spectrum of the fatty acids of the cholesteryl esters was present indicating a normal cholesterol esterification pathway in vivo. Incubation experiments in vitro of plasma from the 2 patients also yielded normal cholesterol esterificaton rates when measured by 2 different methods. These paradoxical results for cholesterol esterification are discussed on the basis of the present biochemical knowledge of fish eye disease and LCAT deficiency.