CFTR and cystic fibrosis: Cystic fibrosis (CF) is the most common autosomal recessive disorder in the Caucasian population and is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene (chromosomal position 7q31.2), leading to altered chloride ion exchange and hyperviscous mucus in the affected organs.