Relationship between clinical phenotype, semen parameters and aneuploidy frequency in sperm nuclei of 50 infertile males

The purpose of this study was to analyse the frequency of disomy for chromo somes 1, 13, 14, 18, 21, 22, X and Y in sperm nuclei of 50 infertile men an d 10 healthy probands of proven fertility Semen parameters (sperm count, gl obal motility and morphology), urological clinical examination, genital ult rasound and lymphocyte karyotyping were performed for each patient. Disomy frequency was established by fluorescence in situ hybridization by using wh ole chromosome paint probes. The mean rate of disomy far the various autoso mes studied was higher in infertile males than in subjects of proven fertil ity. Interchromosomal and interindividual differences in the disomy frequen cy were observed between the 50 patients. The mean frequency of homodisomy YY and heterodisomy XY was increased in spermatozoa of patients with low se men quality parameters (0.24% and 0.54%, respectively). The disomy frequenc y in infertile males was directly correlated with the severity of oligosper mia. However, no relationship was established between aneuploidy rate, sper m motility, morphology or clinical phenotype. These results support the hyp othesis that, during spermatogenesis of males with sperm parameter alterati ons, a decreased frequency of meiotic chromosome pairing and crossing over may lead to spermatogenesis arrest at the meiosis stage and/or to an increa se of meiotic nondisjunctions. Meiotic arrest in some germ cells may be res ponsible far oligospermia and nondisjunctions in other cells for aneuploidy in mature male gametes.