Aneuploidy rate in spermatozoa of selected men with abnormal semen parameters.

Abstract

A large proportion of patients with oligoasthenoteratozoospermia (OAT) have an abnormal karyotype and hence they produce aneuploid gametes. However, a normal karyotype does not exclude the chance of having germ cell aneuploidy, since an altered intra-testicular environment not only damages spermatogenesis, but may also disrupt the mechanisms controlling chromosomal segregation during meiosis. Therefore, this study was undertaken to evaluate the rate of aneuploidy in the spermatozoa of selected patients with abnormal sperm parameters. For this purpose, sperm aneuploidy rate for chromosomes 8, 12, 18, X and Y was evaluated by multicolour fluorescence in-situ hybridization (FISH) in nine patients with teratozoospermia alone and 19 OAT patients of presumably testicular origin. Thirteen normozoospermic healthy men served as controls. Patients with teratozoospermia or OAT had significantly greater disomy and diploidy rates compared with controls, whereas the rate of nullisomy was similar. XY disomy was very low in all groups, suggesting that chromosomal non-disjunction occurs mainly during the second meiotic division. Autosome 12 disomy rate was low in both patients and controls. There was a marked variability of total sperm aneuploidy rate in both groups of patients. Sperm aneuploidy rate was negatively correlated with sperm concentration and particularly with the percentage of normal forms. In conclusion, patients with teratozoospermia or OAT have an increased rate of sperm aneuploidy. This increase is similar in both groups, suggesting that teratozoospermia may be the critical sperm parameter associated with aneuploidy.