It is the most common fatal genetic disease in the developed world; 1 in 25–30 people with Caucasian ancestry carry a single defective copy of the CFTR gene (Cystic Fibrosis Foundation, 2018) and have no symptoms; 1 in ∼3000 babies are born with mutations on both alleles, resulting in the disease. The gene discussed is CFTR; the disease is cystic fibrosis.