BlueCross BlueShield of Tennessee Medical Policy Manual

Genetic Testing (CFTR-mutations) for Cystic Fibrosis


Cystic Fibrosis is an inherited autosomal recessive disease of the exocrine glands associated with a high morbidity. It is characterized by impairment in the transport of chloride and sodium across cell membranes, which can result in an imbalance of water absorption, thereby causing dehydration. The liquid depletion results in the presence of thick and sticky mucus that causes blockage of ducts and tubes in various organs, including the lungs, pancreas, liver and intestines. Symptoms of cystic fibrosis may include chronic sinopulmonary diseases (e.g., chronic cough, bronchiectasis, pneumonia, and sinusitis), digestive complaints (e.g. foul-smelling greasy stools, intestinal blockage, meconium ileus, and failure to thrive, rectal prolapse), and reproductive difficulties (e.g., congenital absence of vas deferens, infertility).

Cystic fibrosis is caused by the presence of a variant on both copies of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Variants in this gene result in impairment of the CFTR protein, which serves as a chloride channel allowing transport of chloride and sodium through the cell membrane. More than 1900 variants have been described in the CFTR gene; however, most of these variants are rare and their functional role has not been elucidated. Genetic testing for CFTR has a number of different applications, which include carrier testing and screening, testing of newborn after a positive screening, and identification of individuals who will benefit from specific drug therapies. The American College of Genetics and Genomics guidelines recommend a 23-variant panel for prenatal/preconception expanded carrier screening. The use of expanded carrier screening panels is not recommended.

As an autosomal recessive disorder, both parents must carry some form of the CFTR gene mutation to have an affected child. Dual carrier parents have a 25% chance of having an affected child, a 25% chance of having an unaffected child, and a 50% chance of having a carrier child.





Laboratories that conduct genetic testing must comply with the provisions of the FDA’s Clinical Laboratory Improvement Act (CLIA).


American Academy of Pediatrics. (2007). Guidelines for implementation of Cystic fibrosis newborn screening program: Cystic Fibrosis Foundation workshop report. Retrieved August 11, 2017 from

American College of Medical Genetics and Genomics. (2004). Cystic fibrosis population carrier screening: 2004 revision of American College of medical Genetics mutation panel. Retrieved August 30, 2017 from

American College of Medical Genetics and Genomics. (2008). Carrier screening in individuals of Ashkenazi Jewish descent. Retrieved August 30, 2017 from

American College of Medical Genetics and Genomics. (2013). ACMG position statement on prenatal/preconception expanded carrier screening. Retrieved August 15, 2016 from

American College of Obstetricians and Gynecologists. (2017). Carrier screening for genetic conditions. Committee Opinion #691. Retrieved August 11, 2017 from

BlueCross BlueShield Association. Medical Policy Reference Manual. (4:2017). Carrier screening for genetic diseases (2.04.107). Retrieved August 11, 2017 from BlueWeb. (31 articles and/or guidelines reviewed)

Ong, T., Marshall, S., Karczeski, B., Sternen, D, Cheng, E., & Cutting, G. (2001, March; last update February 2017). Cystic fibrosis and congenital absence of the vas deferens (Gene Reviews [Internet]), Seattle: Pagon, R.A., Adam, M.P., Ardinger, H.H., et al., editors.




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