Relation between the anatomical genital phenotype and cystic fibrosis transmembrane conductance regulator gene mutations in the absence of the vas deferens.

Objective: To study the correlation between genital phenotype and cystic fibrosis genotype in men lacking at least one vas deferens.

Design: Prospective study.

Setting: Institut Rhônalpin pour la Reproduction Humaine, Lyon-Bron, France.

Patient(s): Forty-seven infertile men lacking at least one vas deferens.

Intervention(s): All patients were screened for the 13 most common CFTR gene mutations and for the 5-thymidine variant of intron 8. Renal, scrotal, and transrectal ultrasonography were systematically performed.

Main Outcome Measure(s): Epididymal and seminal vesicular abnormalities and testicular volume were compared among men with two, one, or no CFTR gene mutation, with or without the 5T allele.

Results: Seminal vesicles and the symmetry of epididymal and vesicular abnormalities did not differ between patients with and those without the CFTR gene mutation. Epididymal abnormalities were more frequent in men without the mutation. Testicular volumes were significantly lower in men without the mutation and those with the 5T allele only.

Conclusion: Men with the CFTR mutation, the 5T allele only, and those without CFTR mutation have few differences in genital phenotype. Low testicular volume is observed in men without the CFTR mutation and those with the 5T allele only.