This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
Wilson's disease is caused by mutation in: 
Select and explain. 
A. ATP7A, B. ATP7B, C. HFE, D. HAMP
B: ATP7B
Answer: B: ATP7B 
Explanation: Wilson disease is an autosomal recessive disorder caused by mutation of the ATP7B gene, resulting in impaired copper excretion into bile and a failure to incorporate copper into ceruloplasmin. Ref: Robbins 8th edition Chapter 18.