Cystic fibrosis results from inheriting a defective gene from both of your parents. In scientific terms, cystic fibrosis is an autosomal recessive genetic disorder. Defective genes result in very sticky and thick mucus in your body. This abnormally thick mucus results in lung, pancreas and digestive problems. It can also cause reproductive issues in men. Approximately 1 in 29 North Americans have one defective gene for cystic fibrosis. If you have one defective gene, you will not show any of the symptoms of cystic fibrosis, but you are a carrier for the condition. This means that if you have children with another person who is a carrier, your children will have a 25 percent chance of inheriting the condition and a 50 percent chance of being carriers themselves. Cystic fibrosis is one of the most common and most serious genetic conditions.
Cystic fibrosis is the result of mutations on the CFTR gene. This defective gene causes problems for the chloride channels on cell membranes in the body. These dysfunctional cells lead to excessively thick mucus. Other genetic and environmental factors can contribute to the severity of cystic fibrosis. To make things even more complicated, cystic fibrosis can result from more than 1,000 different mutations of the CFTR gene.
Your risk of carrying the cystic fibrosis gene depends on your ethnicity. Caucasians of northern European descent are most likely to carry the defective gene. Asians and African-Americans are least likely to carry the cystic fibrosis gene. Testing for the cystic fibrosis gene is relatively simple, involving a cotton swab of the inside of your check. Genetics labs test for the most common cystic fibrosis mutations and generally only test for 30 to 100 different mutations of the CFTR gene.