Medical technology now offers information about the future health of individuals. Using genetic information, tests can be offered to find out if a person might have a child who may have certain diseases or health care needs. Genetic testing looks at the genes that a person has to learn if that person carries an altered gene for cystic fibrosis. An altered gene also may be called a CF mutation. For someone to have this disease, two copies of an altered CF gene must be present-one from each parent. A "carrier" has only one copy of an altered CF gene and therefore does not have CF.
Genetic carrier testing can be used to tell if a person carries one of the altered genes that causes CF. The test looks at a person's DNA (genetic material), which is taken from cells in a blood sample or from cells that are gently scraped from inside the mouth. There are more than 1,000 known alterations of the gene that causes CF. Current tests look for the most common CF gene alterations. A negative test means the person does not carry most of the alterations, but the person still may carry a rare CF gene.
The altered genes that are looked for by the test vary according to a person's race or ethnic group, or if CF occurred already in the family. About 95% of Americans with CF are white or Caucasian. One person in every 29 people who are Caucasian are carriers of an altered CF gene. In other race or ethnic groups, one in 46 Hispanic Americans, one in 65 African Americans and one in 90 Asian Americans carry an altered CF gene. If you have a relative with CF, or who is known to carry the altered CF gene, your chance of carrying the gene is greater because of your family's history. If you are pregnant or planning to have a child, you should discuss this test and the results with a health professional who is knowledgeable about genetic testing, such as a genetic counselor.