Classic cystic fibrosis replicates two malfunctioning transmutations in the CFTR gene and is represented by protracted bacterial infection of the sinuses and airways, fat maldigestion owing to pancreatic exocrine inadequacy, infertility in men due to disruptive azoospermia, as well as high concentrations of chloride in perspiration. The gene discussed is CFTR; the disease is cystic fibrosis.