Problem: Cystic fibrosis is a genetic disease. It's caused by a nonworking gene that a person inherits from their parents. The faulty gene contains an abnormality, called a variant, which changes a protein (known as CFTR) that's responsible for regulating the movement of salt in and out of the body's cells. There are over 1,800 different variants of the CFTR gene known to cause CF when in combination with another disease-causing variant. People with the disease inherit two nonworking copies of the cystic fibrosis gene - one from each parent. Typically both of the parents have at least one copy of the nonworking gene for a child to have CF. If both your parents have a nonworking version of the CFTR gene, you have about a 25 percent chance of developing the disease. If you inherit one copy of the gene, you won't develop cystic fibrosis, but you'll be a carrier and may pass it on to your children. There's also a chance that you won't inherit the cystic fibrosis gene or the disorder even if your parents are carriers. Need Assignment Help?