<prompt> In cystic fibrosis mutation occurs at?One geneTwo geneThree geneFour gene  <response>: Ans. a One geneRef: Robbins 9thpg 466-470Cystic 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. 