Wilson's disease is caused by mutations in ATP7B. Excess copper accumulates causing hepatic and neurological disease. The biochemical reason kayser-Fleischer rings form in Descemet's membrane of the cornea rather than elsewhere is:
- A Ceruloplasmin deposits in corneal stroma where it oxidises copper to form insoluble green cupric complexes
- B Descemet's membrane has high collagen content with thiol groups that chelate and trap copper
- C Copper deposited in the lens epithelium migrates posteriorly to Descemet's membrane
- D The corneal endothelium has no lymphatic drainage; copper that diffuses from aqueous humour deposits in the avascular Descemet's membrane without being cleared ✓
Explanation
Kayser-Fleischer (KF) rings are golden-brown to greenish rings at the periphery of the cornea, located in Descemet's membrane (the basement membrane of corneal endothelium). They form because copper in the aqueous humour (elevated due to hepatic copper overload) diffuses into the avascular, alymphatic corneal stroma and specifically accumulates in Descemet's membrane at the periphery (Schwalbe's line). The avascular nature of the cornea means there is no systemic clearance mechanism for deposited copper. The peripheral location reflects the proximity to limbal vasculature where copper enters. KF rings are not formed by ceruloplasmin deposits; ceruloplasmin is actually low in Wilson's disease.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.