141 - Cystic Fibrosis

Abstract

Cystic fibrosis is a single-gene autosomal recessive disorder characterized by chronic airway infection, pancreatic insufficiency, gastrointestinal dysfunction, and male infertility. Cystic fibrosis is caused by a mutation in the cystic fibrosis membrane conductance regulator (CFTR) protein. Mutations in the responsible gene, located on chromosome 7, lead to an absent, nonfunctional, or partially functional protein, with resultant abnormal fluid and electrolyte transport across cells. Over 1000 different mutations in the CFTR gene have been identified with an expansive ethnic and racial distribution as well as varying phenotype and penetrance. The current prenatal detection rate of cystic fibrosis carriers in the general population using a standard 23 mutation panel ranges from 30%–97% depending on racial/ethnic origin. Greater than 90% of cystic fibrosis patients manifest symptoms in early childhood, often leading to an increased mortality rate in the third and fourth decades of life. Sonographic findings linked to cystic fibrosis include echogenic bowel, nonvisualization of the gallbladder, and dilated bowel; however, none are diagnostic. Prenatal carrier screening should be made available to all patients regardless of ethnicity, and invasive prenatal diagnostic testing should be considered in cases of two known parental mutations, family history of cystic fibrosis, and/or the sonographic finding of echogenic bowel.