A 50-year-old man has fasting triglycerides of 600 mg/dL, total cholesterol of 300 mg/dL, and pathognomonic orange-yellow striations of the palmar creases. Lipoprotein electrophoresis shows a broad beta band. His apolipoprotein E genotype is E2/E2 homozygous. The lipoproteins accumulating in his plasma are:

• A Chylomicrons and VLDL
• B LDL particles only
• C Chylomicron remnants and IDL ✓
• D Nascent HDL discs

Explanation

Familial dysbetalipoproteinemia (type III hyperlipoproteinemia) arises when homozygous apoE2, which binds hepatic remnant receptors poorly, impairs clearance of chylomicron remnants and IDL, both enriched in apoE. Palmar xanthomas are virtually diagnostic. Chylomicrons and VLDL accumulate in type I and type V patterns driven by LPL or apoC-II defects, and LDL elevation defines types IIa and IIb instead.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.