[Mutation in the cystic fibrosis transmembrane-regulator gene in bilateral congenital ductus deferens aplasia].

A 28-year-old man and his 27-year-old wife were investigated for infertility of 3 1/2 years' duration. There was azoospermia caused by bilateral aplasia of the vas deferens, and therefore it was planned to aspirate spermatozoa from the epididymis for the purpose of in-vitro fertilisation. As part of the diagnostic workup the man was investigated for those mutations of the cystic fibrosis transmembrane regulator (CFTR) gene which occur with undue frequency in association with aplasia of the vas deferens. Deoxyribonucleic acid (DNA) analysis revealed a typical three base deletion (delta F 508). In the wife, CFTR gene mutations were excluded with 80% probability. The likelihood of cystic fibrosis in this couple's children was accordingly estimated to be about 0.2%--an acceptable risk. Assisted fertilization in patients with bilateral aplasia of the vas deferens should not be undertaken until they have been thoroughly investigated and informed of the risks.