Question

what is the most common mutation that causes cystic fibrosis?
○ a deletion mutation on chromosome 7
○ a deletion mutation on the x chromosome
○ a missense point mutation that causes valine to replace glutamic acid
○ a frameshift mutation on chromosome 4

Explanation:

Cystic fibrosis is mainly caused by mutations in the CFTR gene located on chromosome 7. The most common mutation is a deletion of three base pairs (ΔF508) in this gene, which is a deletion mutation on chromosome 7. A deletion mutation on the X - chromosome is not relevant as the CFTR gene is not on the X - chromosome. A missense point mutation that causes valine to replace glutamic acid is related to sickle - cell anemia (mutation in the HBB gene). A frameshift mutation on chromosome 4 is not the cause of cystic fibrosis.

Answer:

a deletion mutation on chromosome 7