Cystic fibrosis is a genetically inherited disease, meaning it is passed on from parents—who may not even know they carry the gene for the disease—to their child. There are two potential causes of cystic fibrosis:
- Genetic mutation: Patients with cystic fibrosis inherit two copies of a defective gene from their parents.
- Autosomal recessive inheritance: The mutated gene is inherited as an autosomal recessive trait, meaning the child must inherited one mutated, recessive gene from each parent to develop the disease.
Carriers—those who have one mutated gene and do not experience symptoms of cystic fibrosis—have a 50 percent chance of passing the mutated gene to their children. Both parents must be carriers of the disease for their children to develop it. If both are carriers, each child has a 50 percent chance of being a carrier and a 25 percent chance of inheriting the disease. If both parents have cystic fibrosis, each of their children has a 100 percent chance of inheriting cystic fibrosis.
While genetics and family history play a role, so too does race. Researchers estimate that five percent of Caucasians carry the gene for cystic fibrosis, and one out of every 3,500 Caucasians born in the United States has cystic fibrosis, while one in 15,000 African Americans, one in 9,200 Latinos, and one in 31,000 Asian Americans are.