Familial type V hyperlipoproteinaemia in identical twins homozygous for apoliprotein variant E2: report.

Hyperchylomicronaemia and elevated very low density lipoproteins were found in relatively obese 47 year old identical twin brothers. Lipoprotein apoprotein studies showed the presence of apoprotein CII, the activator of lipoprotein lipase, and both men were homozygous E2/2. Studies on the ability of the brothers to clear triglyceride rich particles showed some impairment of post heparin lipase activity, and a slower clearance of infused fat emulsion. The values improved after weight loss. There was some evidence of impaired capacity of the patients' high density lipoprotein to activate post heparin lipoprotein lipase.