This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics, Subject name: Medicine
Gene mutations in Cystic fibrosis occurs at - 
Select and explain. 
A. Sho arm of chromosome 7, B. Long arm os chromosome 5, C. Long arm of chromosome 7, D. Sho arm of chromosome .3
C: Long arm of chromosome 7
Answer: C: Long arm of chromosome 7 
Explanation: In cystic fibrosis, CFTR gene mutation occurs on the long arm of chromosome 7 Reference: Ghai essential pediatrics, 9 th edition, page 392