Wilson's disease is a genetic disorder of copper metabolism. The defective protein ATP7B normally functions to:

• A Transport copper from portal blood into hepatocytes via the liver sinusoidal surface
• B Reduce dietary Cu2+ to Cu+ for duodenal absorption via Ctr1 transporter
• C Shuttle copper to mitochondrial cytochrome c oxidase as a copper chaperone
• D Incorporate copper into ceruloplasmin in the trans-Golgi network and export excess copper into bile via the canalicular membrane ✓

Explanation

ATP7B is a P-type Cu-ATPase located predominantly in hepatocyte trans-Golgi network. It has a dual role: under normal copper load, it incorporates copper into the cuproenzyme ceruloplasmin; when copper is excess, it traffics to the canalicular membrane to export copper into bile for faecal excretion. Loss-of-function mutations impair both biliary copper excretion and ceruloplasmin loading — causing hepatocellular copper accumulation, low serum ceruloplasmin, and Kayser-Fleischer ring formation from corneal copper deposition.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.