CFTR and hereditary disease: Cystic fibrosis (CF) is a hereditary recessive genetic disease that affects several organs and systems because of dysfunction of the CFTR (cystic fibrosis transmembrane conductance regulator) protein.1 In spite of therapeutic improvements in recent years, according to the Brazilian Cystic Fibrosis Registry (Registro Brasileiro de Fibrose Cística), the median age at death is 19.4 years.2 Malnutrition and recurrent pulmonary exacerbations are recognized strong predictors of CF mortality.3