No intraindividual variation of disomy rate in sperm samples.

We assessed possible inter- and intraindividual variations in the frequency of disomy in sperm cells from three men with abnormal sperm analysis parameters. Mono- and dual-color fluorescence in situ hybridization (FISH) was applied to sperm cells from different samples of the men. Four men with a normal sperm profile were used as controls. The samples were taken separately over a period of 6 months. FISH probes used for the disomy rate analysis were clones from the satellite region of chromosomes 8, 18, X, and Y. The study group showed a significantly higher disomy rate compared with the control group, whereas there was no significant difference in the disomy rate between three different samples from the same individuals. These results suggest that the sampling time has no importance in assessing the rate of nondisjunction in sperm cells.