CFTR and cystic fibrosis: Pathogenic variants of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene, by lowering or abolishing the CFTR Cl- channel activity, cause a broad spectrum of clinical manifestations spanning from Cystic Fibrosis (CF) to the so-called CFTR related disorders (CFTR-RD) [1,2].