While only persons homozygous for two severe pathogenic Cystic Fibrosis Transmembrane conductance Regulator (CFTR) mutations develop the disease CF, men with CFTR compound heterozygoti or a single pathogenic CFTR exon mutation, in some cases combined with an intron 8 5T splice variant, may have CBAVD as an isolated phenotype without symptoms from the respiratory tract and gastrointestinal system.2 The gene discussed is CFTR; the disease is congenital bilateral aplasia of vas deferens from CFTR mutation.