Abstract
Clinical studies, measurement of postheparin lipolytic activity and the analysis of apolipoproteins were performed in patients with hyperchylomicronemia and those with retention of remnants in plasma.
Four patients with hyperchylomicronemia showed a deficiency in lipoprotein lipase (LPL) activity. One of them belonged to a classical form of LPL deficiency. Two other patients, brother and sister, also showed a marked deficiency in LPL activity. However, the addition of normal plasma resulted in a complete recovery of the lipolytic activity and the analysis of chylomicron and VLDL apoproteins showed a deficiency in apo CII. Analysis of apoproteins of the parents showed that apo CII was reduced to approximately half the normal control, suggesting that the parents were heterozygotes (Yamamura, T. et al.: Atherosclerosis in press). The other patient showed a marked decrease both in LPL and hepatic triglyceride lipase (H-TGL) activities and the retention of the remnant was also observed on lipoprotein electrophoresis. Three of his children were normolipidemic, but two of them showed a deficiency in LPL with a normal or increased activity of H-TGL.
Among ten patients with broad x band on PAG disc electrophoresis of lipoproteins, only three fell under a category of Type III hyperlipoproteinemia as defined by chemical indices and clinical symptoms proposed by Fredrickson and Hazzard. A 50-year-old male had a marked hyperlipemia of Type V, but the pattern was changed into broad B type ly dietary fat restriction. One of his daughter died of pancreatitis with hyperchylomicronemia. Another daughter was usually normolipidemic, while a small amount of the remnant was detected on electrophoresis of lipoproteins, and hyperlipidemia was induced by high fat diet. Both of these daughters had xeroderma pigmentosum.
Most of the patients with broad B band showed a decrease in H-TGL activity and the injection of heparin could not succeed in reducing the amount of the remnant. Disturbances in the H-TGL-mediated removal mechanism of the remnant was suggested.
