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Why can cystic fibrosis be tested with DNA analysis or a sweat test?
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human genetic disease
Photomicrograph of the BRCA2 tumor suppressor gene on chromosome 13 of the human genome. Inactivation of this growth-regulating gene is associated with a higher risk of developing breast cancer.
Cystic fibrosis (CF) is a metabolic disorder caused by mutations in the CFTR gene, which encodes a protein responsible for transporting chloride across cell membranes. Because the disease is rooted in both genetic and physiological dysfunction, it can be diagnosed through two distinct approaches:1
- DNA Analysis: Because the specific gene responsible for CF has been identified, recombinant DNA technology and PCR can be used to detect mutations within the CFTR gene. These tests are highly effective for identifying carriers (heterozygotes) who do not manifest the disease, as well as screening newborns at risk for the disorder.12
- Sweat Test: The CFTR protein is critical for regulating the fluidity of secretions in exocrine glands. When the protein is defective, sweat glands produce perspiration with an abnormally high salt content. This physiological manifestation serves as the definitive diagnostic test for the presence of the disease.1
Both methods are essential tools in clinical pathology, allowing for both the identification of genetic risk and the confirmation of clinical symptoms.1