Tangier disease is characterized by nearly absent plasma HDL, cholesterol ester deposition in tonsils and cornea, and premature atherosclerosis. The defective gene encodes:

• A ABCA1 (ATP-binding cassette transporter A1) ✓
• B LCAT (lecithin-cholesterol acyltransferase)
• C Apolipoprotein A-I
• D CETP (cholesteryl ester transfer protein)

Explanation

Tangier disease is caused by mutations in ABCA1, the transporter responsible for effluxing cellular cholesterol and phospholipids onto lipid-poor apoA-I, forming nascent HDL. Without functional ABCA1, reverse cholesterol transport is impaired, HDL is absent or markedly reduced, and cholesterol esters accumulate in macrophages of lymphoid tissues (tonsils appear orange-yellow). LCAT deficiency causes fish-eye disease with low HDL. ApoA-I deficiency is a separate rare cause of low HDL.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.