An influence of the CFTR genotype on semen parameters in CBAVD syndrome patients

CBAVD syndrome (congenital bilateral aplasia of vas deferens) is a bilateral congenital aplasia of the VAS deferens, which is the main genetic cause of male infertility associated with obstructive azoospermia. CBAVD is heterogeneous in nature, in most cases, it is caused by pathogenic variants in the CFTR gene, mutations in other genes can be a rare cause. Although the phenotypic variability of congenital VAS deferens aplasia has been shown, including its morphological variants, the effect of the genotype on the state of the genitals and ejaculate parameters in patients with CBAVD syndrome has not been sufficiently studied. Aim: to evaluate the effect of the CFTR genotype on semen parameters in CBAVD syndrome patients. Materials and methods: a group of 74 unrelated Russian men of reproductive age with a diagnosis of CBAVD syndrome was examined. Molecular genetic analysis included the detection for 22 common pathogenic variants of the CFTR gene, and the IVS8-Tn polymorphic locus in intron 8. Semen analysis was performed in all patients. Results: Pathogenic variants of the CFTR gene were found in 51 of 148 (34,5%) alleles, IVS-T5 (5T) allele variant was revealed in 43 of 148 (29.1%) alleles. A comparative analysis of two groups of patients with pathogenic variants of the CFTR gene (group I) and without them (group II) was performed. Azoospermia was diagnosed in 62 of 74 (83.7%) patients, cryptozoospermia/severe oligozoospermia - in 12 (16.3%) patients. Oligospermia (ejaculate volume less than 1.5 ml) was found in groups I and II in 56 of 61 (91.8%) and 12 of 13 (92.3%) patients, respectively. Increased viscosity was observed in ejaculate samples in 4 (6.6%) patients of group I and 5 (38.5%) patients of group II. Leukospermia was found only in group II, in 3 (4.1%) patients. There were no statistically significant differences in semen parameters between the groups. Obtained data indicate that the CFTR genotype does not significantly affect semen parameters in CBAVD syndrome patients.

CFTR gene, CBAVD syndrome, male infertility, azoospermia

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