Cystic Fibrosis is caused by a genetic defect on which chromosome?

Cystic Fibrosis is caused by a genetic defect on which chromosome?

• A. Mutation on chromosome 12
• B. Mutation on chromosome 7 causing defective chloride transport
• C. Mutation on chromosome 5
• D. Mutation on chromosome 11

Answer: (B)

Cystic fibrosis comes from mutations in the CFTR gene, which encodes a chloride channel that regulates movement of salt and water across epithelial surfaces. The CFTR gene is located on chromosome 7 (7q31.2). When CFTR is defective, chloride transport is impaired, leading to thick, sticky mucus in the airways, pancreas, and other organs. The most common mutation, ΔF508, causes the protein to misfold and not reach the cell surface, further reducing chloride transport. Mutations on other chromosomes do not explain CF, so the defect on chromosome 7 is the correct association.

Cystic fibrosis comes from mutations in the CFTR gene, which encodes a chloride channel that regulates movement of salt and water across epithelial surfaces. The CFTR gene is located on chromosome 7 (7q31.2). When CFTR is defective, chloride transport is impaired, leading to thick, sticky mucus in the airways, pancreas, and other organs. The most common mutation, ΔF508, causes the protein to misfold and not reach the cell surface, further reducing chloride transport. Mutations on other chromosomes do not explain CF, so the defect on chromosome 7 is the correct association.