How are changes in the CFTR gene related to health conditions?
About 80 CFTR mutations have been identified in males with congenital bilateral absence of the vas deferens. Most affected males have a mild mutation in at least one copy of the gene in each cell. These mutations allow the CFTR protein to retain some of its function. Some affected males have a mild mutation in one copy of the CFTR gene in each cell and a more severe, cystic fibrosis-causing mutation in the other copy of the gene. Mutations in the CFTR gene disrupt the function of the chloride channel, preventing the usual flow of chloride ions and water into and out of cells. As a result, cells in the male genital tract produce mucus that is abnormally thick and sticky. This mucus clogs the tubes that carry sperm from the testes (the vas deferens) as they are forming, causing them to deteriorate before birth. Without the vas deferens, sperm cannot be transported from the testes to become part of semen. Men with congenital bilateral absence of the vas deferens are unable to father child
