Disorders of metal metabolism: Wilson and Menkes disease — formative SAQs

SAQ 1 (10 marks)

A 13-year-old boy presents with a six-month history of a progressive tremor, slurred speech and deteriorating school performance. His mother reports he has become irritable and withdrawn. Liver function tests show AST 110 and ALT 88. Slit-lamp examination reveals golden-brown deposits at the periphery of both corneae. ^{[1] [3]}

a) Name the likely diagnosis, the defective gene and its inheritance, and explain the single unifying concept that links this disease to Menkes disease. (2 marks) ^[1]

b) Describe the integrated copper panel you order to confirm the diagnosis, and explain how the Leipzig score (Ferenci 2003) integrates these results into a validated diagnostic instrument. Include the caveat that a normal ceruloplasmin does not exclude the diagnosis. (3 marks) ^{[1] [2]}

c) Outline the definitive medical management of this child, naming the three therapeutic pillars (chelation, zinc, transplant), the mechanism by which zinc acts, and the rationale for preferring trientine over penicillamine for initial therapy in a neurologically presenting patient. (3 marks) ^{[1] [7]}

d) Describe the family screening obligations at this diagnosis, and explain why pre-symptomatic treatment of an affected sibling is one of the most effective interventions in inherited metabolic medicine. (2 marks) ^[1]