Cystic fibrosis is an autosomal recessive disease that occurs in one in every 2,500 live births in many communities. The mutations in the gene that codes the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which acts as a chlorine channel, are responsible for this disease. The epithelial cells in the intestines and respiratory system, pancreatic cells and sweat glands are directly affected by this disease. The increased mucus production accompanying the reduced mucociliary activity results in obstructive pulmonary disease and bacterial infections, which lead to death due to respiratory failure, are the main cause of mortality in patients with cystic fibrosis.
Pancreatic failure may also be observed in patients due to the inability to release sufficient digestive enzymes. 97-98% of men with cystic fibrosis also suffer from azoospermia due to the absence of bilateral congenital vas deferens (CBAVD). In addition, fertility problems may occur in female patients due to impaired cervical mucus quality. To date, approximately 1,800 mutations have been identified in the CFTR gene.
The size of the CFTR gene (27 coding exons) renders the molecular diagnosis of the disease difficult.