No abstract

Spermatozoa from seven healthy donors (two of whom had already fathered children) and five infertile patients taking part in the local programme of intracytoplasmic sperm-injection (ICSI) were investigated for the disomy rates of chromosomes 13/21, 18, X and Y as well as for the diploidy rates. Two- and three-colour fluorescence in situ hybridization (FISH) was applied after a donor-adapted decondensation pre-treatment: in a preliminary decondensation series the optimum fluorescence signals were individually determined by variation of the concentration of the decondensation reagents and the duration of incubation with these reagents. Strict scoring criteria were applied. The average disomy rates ranged from 0.10% (chromosomes 13/21) to 0.44% (disomy XY) in the infertile donors and from 0.07% (disomy XX) to 0.36% (disomy XY) in the controls. The average diploidy rates were 0.22% and 0.20% for the infertile donors and the controls respectively. There was no statistically significant difference between the two groups with respect to the disomy and diploidy rates. Within the two groups there were inter-individual differences which were partly statistically significant, indicating considerable inter-donor variation of the aneuploidy rates.

Objective: Primed in situ labeling (PRINS) is an interesting alternative to the traditional fluorescence in situ hybridization (FISH) for the in situ detection of specific sequences in chromosome anomalies. It combines the sensitivity and specificity of the polymerase chain reaction with the specific in situ signal detection capability of FISH. Methods: We performed PRINS on uncultured amniocytes and compared the results with standard cytogenetic analysis. In a prospective study, a total of 262 independent samples were analyzed for numerical aberrations of chromosome 18. Results: In more than 95% of the cases PRINS reactions were successfully achieved. Neither false-positive nor false-negative results were obtained. 62 of the 262 cases were in parallel examined for chromosome 18 aneuploidies by FISH. Although there were significant differences in signal distribution, these did not lead to a different overall classification of the respective cases, i.e., the end results of disomic and trisomic cases for chromosome 18 were identical between FISH and PRINS. In 205 of 262 cases PRINS was performed for chromosomes X and Y. 97.6% of these samples were properly sex differentiated. Conclusions: The PRINS assay is a simple and cheap alternative to detect numerical aberrations of chromosome 18. However, the rate of false-positive results for chromosome X was calculated as 1% and the rate of false-negative ones for chromosome Y as 2%. Further investigations are required to transform PRINS into an alternative to conventional methods for routine rapid prenatal diagnosis of gonosomes.

Semen samples from 34 men visiting the Lübeck infertility clinic were investigated using a two-color FISH method to determine the ratio of X- and Y-bearing sperm. The overall ratio was significantly shifted to a preponderance of X-containing sperm. A statistical comparison with seven reports from the literature which included 53 normal probands demonstrated in our patients a significant tendency of a preponderance of X-bearing sperm and significantly less Y-bearing sperm. Furthermore, the Lübeck sperm samples are remarkably more heterogeneous in respect to their variability of X- and Y-bearing spermatozoa than in the other mentioned studies with normal probands. These phenomena have to be evaluated in further studies on groups of infertile males showing similar infertility histories.