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If your mom has cystic fibrosis does it mean you will?

You have pairs of genes in your genetic makeup, one inherited from your mother and another inherited from your father. Cystic fibrosis is an autosomal recessive genetic disorder. This means that you must inherit two gene mutations, one from your mother and one from your father, to have cystic fibrosis yourself. Many people are carriers for cystic fibrosis. Carriers inherit one defective gene from one parent and one healthy gene from the other parent. Carriers do not present with any symptoms related to cystic fibrosis but they can pass on the defective gene to their offspring [source: PubMed Health].

The chance of having cystic fibrosis yourself depends on both of your parents' genetics. For example, if your mother has both defective genes but your father has two healthy genes, you have a zero percent chance of having the disorder yourself. You do have, however, a 100 percent chance of being a carrier, since you will inherit one defective gene from your mother. If, on the other hand, your mother has two defective genes and your father has one defective gene, you have a 50 percent chance of having the condition yourself.

Cystic fibrosis is the most common genetic disorder. It occurs most frequently in Caucasians of northern European descent, with approximately 1 out of 3,000 live births presenting with the condition. About 1 in 25 Caucasians are also carriers for cystic fibrosis. If you are concerned about your inheritance of the cystic fibrosis gene, seek genetic counseling. A genetic test simply involves a cotton swab of your inner cheek. Most genetics labs test for 30 to 100 different mutations of the cystic fibrosis gene with very good accuracy [source: Lucille Packard Children's Hospital at Stanford].