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Cystic fibrosis: Carrier screening

Katharine D Wenstrom, MD
Section Editor
Louise Wilkins-Haug, MD, PhD
Deputy Editor
Vanessa A Barss, MD, FACOG


Cystic fibrosis (CF) is a life-limiting autosomal recessive disease affecting the airways, pancreas, liver, intestines, sweat glands, and, in males, the vas deferens. It is the most common monogenic disorder in non-Hispanic whites of Northern European descent, with a carrier frequency of 1/24 to 1/25 and birth prevalence of 1 in 2500. Carrier screening is offered to couples planning pregnancy or in early pregnancy to identify those at risk of conceiving a child with classic CF.

This topic will review CF carrier screening and reproductive options for carrier couples, including prenatal diagnosis. Other issues related to CF are discussed separately, including:

(See "Cystic fibrosis: Clinical manifestations and diagnosis".)

(See "Cystic fibrosis: Genetics and pathogenesis".)


CF is caused by mutations in a single large gene on chromosome 7 that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which regulates chloride channel function of epithelial cells of the sweat gland, airway, pancreas, and intestine. Clinical disease occurs when disease-causing mutations are present in both copies of the CFTR gene. Over 1900 different mutations in the CF gene have been identified, although the vast majority of CFTR mutations occur at frequencies less than 1/1000 (<0.1 percent) [1-3]. The specific mutations that an individual carries are a major determinant of clinical severity. The range of clinical expression likely reflects the degree to which protein function is changed by the mutation, modulation of the phenotype by other genes, and variation in susceptibility to environmental factors. (See "Cystic fibrosis: Genetics and pathogenesis".)

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Literature review current through: Nov 2017. | This topic last updated: Apr 04, 2017.
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