CFTR and congenital bilateral aplasia of vas deferens from CFTR mutation: These variants exhibit striking ethnic discrepancies, with a higher frequency in Caucasians associated with the CAVD phenotype than in non-Caucasians.1 While the 5T variant is often considered a mild variant,8 in combination with (TG)12 or (TG)13 repeats in CFTR intron 8, it may enhance CAVD severity.9