This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Polycystic Kidney Disease, Subject name: Pathology
Mutation in PKHD1 gene causing autosomal recessive polycystic kidney disease (ARPKD) maps to which chromosome? 
Select and explain. 
A. 16, B. 4, C. 6, D. 12
C: 6
Answer: C: 6 
Explanation: Mutations of the PKHD1 gene, which maps to chromosome region 6p21-p23. Expressed in adult and fetal kidney, also in liver and pancreas. PKHD1 gene encodes fibrocystin.