A 35-year-old man presents with eruptive xanthomas over the buttocks and back, severe abdominal pain, and serum triglycerides of 4800 mg/dL. Plasma turbidity clears at 4°C (cream layer forms at the top). Lipoprotein electrophoresis shows a prominent chylomicron band. Deficiency of which enzyme or protein is the most likely cause?

• A Lecithin-cholesterol acyltransferase (LCAT)
• B Hepatic lipase
• C Lipoprotein lipase (LPL) ✓
• D Cholesterol ester transfer protein (CETP)

Explanation

Familial lipoprotein lipase deficiency (Type I hyperlipoproteinemia) presents with massive hypertriglyceridemia due to failure to clear chylomicrons from plasma. LPL, located on capillary endothelium in adipose and muscle, hydrolyzes triglycerides in chylomicrons and VLDL; its deficiency leads to chylomicron accumulation (cream layer on refrigeration), eruptive xanthomas, and recurrent pancreatitis from extremely high triglycerides.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.