In Wilson's disease (hepatolenticular degeneration), the defective ATP7B protein fails to incorporate copper into ceruloplasmin and excrete it into bile. Kayser-Fleischer rings form due to copper deposition in which structure?

• A Posterior capsule of the lens
• B Descemet's membrane of the cornea (limbal region) ✓
• C Anterior epithelium of the cornea
• D Iris stroma at the pupillary margin

Explanation

Kayser-Fleischer rings in Wilson's disease consist of granular copper deposits in the peripheral Descemet's membrane (the posterior elastic lamina of the cornea) at the limbus (corneoscleral junction), visible as golden-brown rings at the periphery of the iris when viewed with a slit lamp. They are present in virtually all patients with neuropsychiatric Wilson's disease and in ~50% of those with hepatic presentation. ATP7B (copper-transporting ATPase) normally loads copper onto apoceruloplasmin and packages excess copper into bile vesicles; its loss leads to free copper accumulation in liver, brain, kidneys, and cornea. The lens capsule is not involved.

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

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Written and medically reviewed by the StethoPrep medical team.