Transient lipoprotein lipase deficiency with hyperchylomicronemia.

Type I hyperlipoproteinemia is a rare disorder characterized by the presence of chylomicrons in fasting plasma and dysfunction of the lipoprotein lipase system. The disease may result from primary genetic defects leading to the lack of the enzyme lipoprotein lipase or to a deficiency in the CII apoprotein activator of that enzyme. It may also appear secondary to underlying systemic diseases. We now describe a case of hyperchylomicronemia and pancreatitis with a lack of lipoprotein lipase activity as assessed by three different methods. The patient had no evidence of a plasma inactivator of lipoprotein lipase, and his plasma was able to activate the enzyme in control postheparin plasma. The postheparin plasma hepatic triglyceride lipase was normal. Tests for associated systemic diseases were negative. Six weeks after presentation, that patient's lipoprotein levels and postheparin plasma lipase activities were normal. This was a unique case of hyperchylomicronemia which for a limited time was indistinguishable from primary lipoprotein lipase deficiency by current biochemical techniques.