Probability of Being a Cystic Fibrosis Carrier

Cystic fibrosis (CF) carrier status affects approximately 1 in 25 Americans of European descent (about 4%). Among other ethnic groups, carrier rates are lower: about 1 in 46 for Hispanic Americans, 1 in 65 for Black Americans, and 1 in 90 for Asian Americans. When two carriers have a child, there is a 25% chance the child will have CF.

CF affects approximately 1 in 3,500 births (about 1,000 new cases per year in the US), with roughly 40,000 Americans currently living with the disease. CF is caused by mutations in the CFTR gene, with the most common mutation being F508del (present in about 70% of CF patients). The disease causes thick, sticky mucus to build up in the lungs, digestive tract, and other organs.

The introduction of CFTR modulator therapies has been transformative: elexacaftor/tezacaftor/ivacaftor (Trikafta), approved in 2019, has dramatically improved lung function and quality of life for about 90% of CF patients. Median predicted survival has improved from about 30 years in 2000 to over 55 years today. Carrier screening is now recommended for all pregnant women or those planning pregnancy, regardless of ethnicity.