Cystic fibrosis is the most frequent lethal recessive autosomal disease in the Caucasian race. It is due to defects in the CFTR gene, which regulates ion transport through the cell membrane. As a consequence, secretions usually turn abnormally thick and stringy, obstructing conducts at different organs. Typical symptoms include pulmonary manifestations with recurrent infections, bronchiectasis and deteriorated pulmonary function, digestive manifestations (recurrent pancreatitis, pancreatic insufficiency, bowel obstruction, and malnutrition), growth retardation, and male infertility.
The diagnosis of CF requires that both internationally accepted diagnosis criteria are met:
- Symptoms consistent with CF in one or more organs or a positive result from neonatal screening tests or a sibling diagnosed with cystic fibrosis.
- CFTR gene dysfunction evidenced by increased chlorine concentration in sweat >60 mmol/L or altered nasal transmembrane potential or presence of two CF-related mutations in each one of the gene’s alleles.
In addition to its role in the diagnostic process, the study of other family members, and prenatal genetic counseling, testing for mutations in the CFTR gene is compulsory to make therapeutic decisions, as new CFTR modulators are indicated for patients carrying specific variants.
