Type | Inheritance | Pathogenesis | ↑ Blood Levels | Clinical |
I—Hyperchylomicronemia | AR | Lipoprotein or apolipoprotein C-II deficiency | Chylomicrons, TG, cholesterol | Pancreatitis, hepatosplenomegaly, lipemia retinalis and eruptive/pruritic xanthomas (no ↑ risk for atherosclerosis). Creamy layer in supernatant. |
II—Familial hypercholesterolemia | AD | Absent or defective LDL receptors, or defective ApoB-100 | IIa: LDL, cholesterol
IIb: LDL, cholesterol, VLDL |
Heterozygotes (1:500) have cholesterol ≈ 300mg/dL; homozygotes (very rare) have
cholesterol ≈ 700+ mg/dL. Accelerated atherosclerosis (may have MI before age 20), tendon (Achilles) xanthomas, xanthelasmas and corneal arcus. |
III—Dysbetalipoproteinemia | AR | Defective ApoE3 & E4 | Chylomicrons, VLDL | Premature atherosclerosis, tuberoeruptive & palmar xanthomas. |
IV—Hypertriglyceridemia | AD | Polygenic protein defect → hepatic overproduction of VLDL | VLDL, TG | Hypertriglyceridemia (>1000 mg/dL) can cause acute pancreatitis, coronary artery disease. Related to insulin resistance. |