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: Medicine
Most common mutated gene in primary hemochromatosis 
Select and explain. 
A. HFE gene, B. Transferrin receptor 2, C. Ferroportin 1, D. Hepcidin
A: HFE gene
Answer: A: HFE gene 
Explanation: Primary hemochromatosis - HFE gene Chr6P.