This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disease of Infancy & Childhood, Subject name: Pathology
[{'content': 'In cystic fibrosis mutation occurs at? \nSelect and explain. \nA. One gene, B. Two gene, C. Three gene, D. Four gene', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) One gene(Ref: Robbins 9th/pg 466-470)Cystic Fibrosisis an Autosomal recessive disease, caused by mutation in Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene on chr7q31.2, which leads to abnormal function of ion transport channel.', 'role': 'assistant'}]