Apolipoprotein CII Deficiency

Abstract

The importance of lipoprotein lipase in the catabolism of chylomicrons has been recognized since the discovery of a deficiency of this enzyme in familial Type I hyperlipoproteinemia. Although apolipoprotein CII (apo CII) was demonstrated to be important in the activation of lipoprotein lipase in vitro a definitive role for apo CII for catabolism in vivo of triglyceride rich lipoproteins was clearly established with the report of a patient lacking this apoprotein (Breckenridge et al. 1978). The patient had an apparent deficiency of post heparin lipoprotein lipase which was obviated upon addition of apo CII. Furthermore, the patient’s plasma triglycerides could be reduced by infusions of plasma or apo VLDL from normal subjects. As a result of family studies of the proband we reported (Cox et al. 1978) that apo CII deficiency appeared to be inherited as an autosomal recessive trait. This report describes the results of our continuing study of a rather large pedigree containing 14 homozygous subjects and 23 obligate heterozygotes identified at present.

Supported in part by a contract from National Institutes of Health (NIH-NHLBI 1-HV2-2917-L) and by the Ontario Heart Foundation.