CFTR and Azoospermia: The prevalence of azoospermia was significantly higher in patients with 47, XXY karyotype (19, 100%) than in the groups with other chromosomal abnormalities (3, 42.9%; p < 0.001), CFTR gene mutations (17, 73.9%; p = 0.02), and Y microdeletion (10, 71.4%; p = 0.02).