Atherosclerosis plasma lipoprotein patterns

Familial lipoprotein lipase deficiency is characterized by a massive accumulation of chylomicrons and a corresponding increase in plasma triglycerides or a type I lipoprotein pattern. Presenting manifestations include repeated attacks of pancreatitis and abdominal pain, eruptive cutaneous xanthomatosis, and hepatosplenomegaly beginning in childhood. Symptom severity is proportional to dietary fat intake, and consequently to the elevation of chylomicrons. Accelerated atherosclerosis is not associated with this disease. 

Patient Population. The proband of the B family, T.B., was referred to the Lipid Research Clinic at The Johns Hopkins Hospital at the age of five years because of hypercholesterolemia of 900 mg/100 ml. She had multiple planar xanthomas that had first appeared at three years of age. The patient was free of symptoms of ischemic heart disease. The index lipoprotein pattern was type lib (57), with marked hypercholesterolemia, hyperbeta-lipoproteinemia, a mild hyperprebetalipoproteinemia and hypertriglyceridemia. None of the relatives of T.B. had xanthomas or corneal arcus one (J.S.) developed signs of premature coronary atherosclerosis at the age of 43 years. Increased total plasma and LDL cholesterol levels were transmitted over three generations on both maternal and paternal sides of the family (Fig. I). The parents of the proband, S.B. and K.B., had endogenous hypertriglyceridemia as well. Two normolipidemic members of this family (S.B., Jr. and E.B.), were also studied. 

A. Familial lipoprotein lipase deficiency (Type I lipoprotein pattern on electrophoresis). Serum triglycerides become elevated with particular elevation of chylomicrons. Tliere are xanthomas, rather than atherosclerosis. Pancreatitis may result from the action of pancreatic lipase on these elevated chylomicrons, with resultant excess triglyceride breakdown in the pancreas, pancreatic injury, and release of more pancreatic lipase. (Note that the body contains different kinds of lipases. There is a pancreatic lipase, which is a digestive enzyme a lipoprotein lipase, which is an extracellular enzyme that breaks down plasma triglycerides, thereby enabling fatty acids to enter cells and an intracellular lipase that breaks down stored triglycerides). 

---