Male meiotic segregation of gonosomes analysed by two colour FISH in human interphase spermatozoa

Comparative study of disomy and diploidy rates in spermatozoa of fertile and infertile men: a donor-adapted protocol for multi-colour fluorescence in situ hybridization (FISH)

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.

Comparison of sex chromosome aneuploidy in spermatozoa of fertile men and those requiring ICSI treatment detected by fluorescence in situ hybridization

OBJECTIVE

To compare the frequencies of aneuploidy for chromosomes X, Y and 18 in spermatozoa of infertile and fertile males, using 3-color fluorescence in situ hybridization.

METHODS

Twelve infertile patients who underwent intracytoplasmic sperm injection treatment at Queen's Medical Centre, Nottingham were studied. Three fertile men served as controls. Aneuploidy frequencies in both groups were compared using 2-sample t-tests.

RESULTS

A total of 26,615 ad 93,649 cells were scored in the control and infertile groups respectively. The frequencies of diploidy, sex chromosome disomy and chromosome 18 disomy in the fertile (0.11, 0.28 and 0.11%) compared to the infertile males (0.05, 0.18 and 0.06%) were not statistically significantly different.

CONCLUSION

Our preliminary data do not indicate an increased risk from paternal origin sex chromosome aneuploidies in ICSI. However, we recommend further investigations of the cytogenetic constitution of spermatozoa from severe male factor patients.

Sex chromosomal analysis of spermatozoa from infertile men using fluorescence in situ hybridization

PURPOSE

To confirm an association between male infertility and chromosome aberrations of spermatozoa, we demonstrated the frequency of numerical abnormalities of spermatozoa from infertile men with abnormal semen parameters compared with fertile controls.

METHOD

Sperm cells from 10 infertile patients were investigated for disomy rates of sex chromosomes and chromosome 18 and diploidy by fluorescence in situ hybridization (FISH). All patients showed oligoasthenozoospermia with sperm counts 3-20 x 10(6)/ml and motile rates 0-40%.

RESULTS

Regarding XY disomy, a significantly higher frequency was found in 8 of 10 patients as compared to normal fertile men. The disomy rates of chromosome 18, XX, YY, and diploidy rate were not increased.

CONCLUSIONS

There is an association between male infertility and embryo with aneuploidy of sex chromosomes. Counseling about possible genetic risks should be provided to the infertile couples planning assisted reproduction treatment.

Preconceptional sex selection: past, present, and future

Predetermination of sex in human and in farm animals is reviewed. Preconceptional sex selection has generated great interest and controversy over the years. Medical and commercial benefits outweigh the ethical issues. Technology has not yet provided a routine method for separating the X- and Y-chromosome-bearing sperm. Flow cytometry is the only technique that produces a clinically significant enrichment of X- or Y-bearing spermatozoa However, concern has been raised about the methodological implications of the flow technique because of the use of DNA stains and UV light. Some other techniques, such as gradient columns, appear to produce a slight enrichment of one type of sperm over the other, but this level of enrichment appears unlikely to affect the sex ratio at birth. It thus remains speculative whether 100% pure preparation of X or Y sperm can be obtained unless a major improvement in methodology is achieved. Fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) are currently the methods of choice for evaluating the validity of the sex selection procedure. In view of the extraordinary pace of the technological and scientific progress, it can be expected that the clinical and commercial application of the technology of preconceptional sex selection by X and Y sperm separation will be a reality in near future.