MRCP UK EXAMINATIONS

Detailed explanation-1: -A person must inherit two copies of the CFTR gene that contain mutations-one copy from each parent-to have cystic fibrosis.

Detailed explanation-2: -The Cystic Fibrosis Gene Everyone inherits two copies of the CFTR (cystic fibrosis transmembrane conductance regulator) gene. However, some of the inherited copies are mutations. To date, over 700 mutations of the CFTR gene have been identified. A person with CF inherits two mutated copies of the CFTR gene.

Detailed explanation-3: -All people have two copies of the CFTR gene, and there must be mutations in both copies to cause CF. More than 1, 700 mutations of the CFTR gene have been identified. Although some are common, others are rare and found in only a few people.

Detailed explanation-4: -Mutations. More than 2500 different mutations in the CFTR gene have been described. Most of these mutations either substitute one base – the building material of DNA – for another, or delete a small number of DNA bases. The most common CFTR mutation, present in approximately 70 percent of people with CF, is F508del.

Detailed explanation-5: -To date, more than 2, 000 different mutations of the CFTR gene that cause cystic fibrosis have been identified, but only a few of the mutations are common.