Primary type I hyperlipoproteinaemia--a metabolic and family study.

Primary Type I Hyperlipoproteinaemia is the rarest phenotype of the inherited hyperlipidaemias. A study of the plasma lipids, lipoprotein distribution and apoprotein concentrations has been carried out in a propositus and in three generations of her immediate family, as has associated post heparin lipolytic activity (PHLA). The propositus presented in infancy with spontaneous bruising and abdominal pain. She has gross chylomicronaemia in the presence of depressed PHLA, which is due to deficiency of lipoprotein lipase. Apo Al and B levels are depressed in concert with low density and high density lipoproteins. Introduction of a low fat diet has resulted in loss of symptoms but plasma lipids remain abnormal. Within her immediate family, six of nine members have depressed PHLA. Two such members have elevated plasma triglycerides, one associated with hypercholesterolaemia and peripheral vascular disease. Low PHLA in this family is then associated with different lipoprotein phenotypes.