Wilson disease (hepatolenticular degeneration) results from mutations in ATP7B. Which statement best describes the consequence of ATP7B dysfunction?

• A Defective copper absorption in the intestine resulting in copper deficiency
• B Increased hepatic iron uptake due to competitive binding with copper transport
• C Failure of copper incorporation into ceruloplasmin and failure of biliary copper excretion, leading to copper accumulation ✓
• D Loss of copper-zinc SOD activity causing increased oxidative stress without systemic copper accumulation

Explanation

ATP7B is a P-type ATPase that performs two critical functions in hepatocytes: incorporating copper into apoceruloplasmin to form ceruloplasmin, and excreting excess copper into bile for fecal elimination. Mutations in ATP7B abolish both functions, causing copper to accumulate in hepatocytes (leading to cirrhosis), brain basal ganglia (neuropsychiatric symptoms), and Descemet's membrane of the cornea (Kayser-Fleischer rings). Ceruloplasmin levels are low because it cannot be loaded with copper. Menkes disease causes defective copper absorption/transport, not Wilson disease.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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