Cystic fibrosis phenotype evaluation and paternity outcome in 50 males with congenital bilateral absence of vas deferens

BACKGROUND: Most infertile males with congenital bilateral absence of vas d eferens; (CBAVD) carry mutations on the cystic fibrosis transmembrane condu ctance regulator gene and may express mild cystic fibrosis (CF) symptoms. B arriers to paternity for these men can now be overcome by assisted reproduc tion. Our aims were to investigate the CF-related phenotype and clinical ou tcome for 50 patients with CBAVD seen at a CF adult centre between 1992 and 1999. METHODS AND RESULTS: The investigation of the patients included scre ening for 22 CF mutations and identification of the poly-T variant of intro n 8, sweat testing, clinical investigation for CF-related extra-genital man ifestations, and genetic counselling. CFTR mutations were detected on 56 al leles of the 50 patients. A total of 15 (30%) was compound heterozygote and 26 (52%) heterozygote. In all, 38% of the patients had a positive sweat te st. Four patients were diagnosed with typical CIT not detected previously. Twenty-one patients became fathers following ICSI (eight cases), artificial insemination by donor or IVF with sperm donor (seven cases) or through ado ption (six cases). A mail survey allowed the identification of CF-related c linical symptoms. Information on the occurrence of CF-related symptoms was obtained for 58.5% of patients: in the absence of initial symptoms, no new clinical signs were reported. CONCLUSION: Patients diagnosed with CBAVD nee d genetic counselling before assisted reproduction. Even when no wish for p aternity is expressed, CF gene screening should be associated with at least a sweat test and clinical evaluation because of possible mild forms of CF disease. Medical follow-up did not reveal any new symptoms.