Abnormal Lipoprotein Lipase in Familial Exogenous Hypertriglyceridemia

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Abstract

A 5-yr old male proband and his sister have had hypertriglyceridemia and hepatosplenomegaly since birth. When studied on a metabolic ward, they demonstrated rapid decreases in serum triglycerides on 3 g fat/day diets. Oral glucose tolerance tests were normal. Postheparin lipolytic activity (PHLA) against chylomicrons was virtually absent in both children whereas the mother and a normolipemic sister had levels approximately 50% normal. However, all four had a normal PHLA against commercial triglyceride emulsion (Intralipid). Two unrelated children from different kindreds of typical type 1 hyperlipoproteinemia and two patients with acquired type V hyperlipoproteinemia had deficient PHLA against both substrates. No inhibitors of PHLA could be demonstrated in the proband's plasma, and his own PHLA could not be enhanced by either normal concentrated plasma or pooled d > 1.063 lipoprotein fraction. The proband's postheparin plasma required almost 20 times the normal chylomicron-triglyceride concentration to reach one-half maximal lipase velocity.

Authors

Paul H. Schreibman, Daniel L. Arons, Christopher D. Saudek, Ronald A. Arky