A 30-year-old woman is brought to the physician because of a rash on her arms for 2 months and severe abdominal pain for the past 24 hours. She indicates that she has had intermittent upper abdominal pain during the past 1 to 2 years. Physical examination shows yellow papules on the extensor surfaces of the upper extremities. Palpation of the epigastric region of her abdomen causes pain. Her blood work shows serum amylase activity is increased and fasting serum concentrations of chylomicrons and triglycerides are markedly increased. Which of the following changes in apolipoprotein concentrations is most likely in this patient?

Question

Quizplus · Accepted Answer

ApoC-II is present in chylomicrons, LDL, and HDL and is required for the activation of the endothelial cell-associated triglyceride lipase called lipoprotein lipase (LPL). Loss, or defective activity, of apoC-II would result in circulating lipoproteins of all types enriched in triglyceride, leading to hypertriglyceridemia. Additional symptoms associated with apoCII deficiency include eruptive xanthomas, pancreatitis, and hepatosplenomegaly. The hepatosplenomegaly is the cause of the episodic epigastric pain. The patient's symptoms and lab findings suggest hyperlipoproteinemia, specifically Type I hyperlipoproteinemia (familial lipoprotein lipase deficiency), which is associated with decreased apoC-II, a cofactor necessary for lipoprotein lipase activity.

A 30-Year-Old Woman Is Brought to the Physician Because of a Rash