Do Cystic Fibrosis Carriers have Symptoms?

Individuals who are carriers of cystic fibrosis (CF) do not typically exhibit symptoms of the disease. CF is an autosomal recessive genetic disorder caused by mutations in both copies of the CFTR gene. Carriers, also known as heterozygotes, have one mutated CFTR gene and one normal CFTR gene.

The presence of one normal gene usually allows carriers to have normal functioning CFTR channels, which help regulate the movement of salt and fluids in and out of cells. It is the presence of two mutated CFTR genes that leads to the development of cystic fibrosis.

Carriers of the CF gene mutation are generally healthy and do not experience the chronic respiratory and digestive issues characteristic of cystic fibrosis. Their respiratory and digestive systems typically function normally.

However, carriers can pass the CF gene mutation to their offspring. When both parents are carriers (each with one mutated CFTR gene), there is a 25% chance that their child will inherit two mutated CFTR genes and, thus, have cystic fibrosis. Genetic testing and counseling are recommended for couples who are carriers to understand their risks and make informed family planning decisions.