A change in a gene code, meaning the gene gives faulty instructions to the cell.
A mutation is a change in a gene. A mutated gene gives faulty instructions to cells. Cystic fibrosis is caused by mutations in the CFTR gene. People with cystic fibrosis inherit mutated CFTR from each of their parents. These mutations can be the same or different.
Read our article explaining how mutations in the CFTR gene can cause cystic fibrosis.