Study of the occurrence of interchromosomal effect in spermatozoa of chromosomal rearrangement carriers by fluorescence in-situ hybridization and primed in-situ labelling techniques

Abstract

The possibility that a chromosomal rearrangement might disturb the meiotic behaviour of chromosomes not involved in the rearrangement and favour non-disjunction is a controversial issue in human cytogenetics. Using two-colour fluorescence in-situ hybridization and primed in-situ labelling techniques, we have investigated the segregation pattern of 10 chromosomes (chromosomes 1, 4, 9, 13, 15, 16, 20, 21, X and Y) in spermatozoa from nine carriers of balanced structural rearrangements and three normal men. The patients were divided into two groups according to their semen parameters. In rearrangement carriers and normal subjects, sex chromosomes and chromosome 21 displayed a higher rate of disomy than the other chromosomes. No evidence for the occurrence of interchromosomal effect was found in the spermatozoa of fertile rearrangement carriers, but significant variations were observed for all chromosomes tested in the group of infertile translocation carriers, suggesting a direct correlation between poor quality spermatozoa and increased aneuploidy rate in this group. In fertile carriers of chromosomal rearrangements, the occurrence of non-disjunction of chromosomes not involved in the rearrangement might therefore be considered as fortuitous, whereas in infertile carriers, the risk for interchromosomal effect appears to be real and should be taken into consideration in the genetic counselling of infertile couples with a male partner carrying a chromosomal rearrangement.

Case report: elevated sperm aneuploidy levels in an infertile Robertsonian translocation t(21;21) carrier with possible interchromosomal effect

“…In our study elevated aneuploidy frequencies are obviously correleted with olioastheno-teratozoospermia. The translocation product of this translocation carrier might further contribute to aneuploidy by ICE [26]. These data are in line with findings of this case report and suggest molecular cytogenetic analysis of spermatozoa to be a valuable tool in assessing a genetic basis of severe forms of male infertility.…”

18, X, Y aneuploidies and transmission electron microscopy studies in spermatozoa from five carriers of different reciprocal translocations

“…ICE of some specific chromosomes was detected in male carriers of translocation, although the origin of the increased aneuploidy rates could be related to the oligoasthenoteratozoospermia usually present in most patients enrolled in these studies. Pellestor et al [11] clearly highlighted no evidence for the occurrence of ICE in spermatozoa of fertile rearrangement carriers, but significant variations were observed in the groups of translocation carriers with altered semen parameters, suggesting a direct correlation between poor quality spermatozoa and increased aneuploidy rate. These re sults are consistent with the study of Vegetti et al [6] and the present study, in which a higher incidence of aneuploidies in spermatozoa from infertile men with abnormal karyotype was detected.…”

“…Pellestor et al [11] analyzed sperm samples from eight carriers of translo cation divided into two groups: the first group having nor mal semen features and the second having oligoastheno zoospermia; the diploidy rate was higher in both groups compared with controls whereas the disomy rates of 13, 21, X and Y and XY were higher in the sole group with abnormal semen.…”

Estimation of the proportion of genetically unbalanced spermatozoa in the semen of boars carrying chromosomal rearrangements using FISH on sperm nuclei

“…The proportions of disomic 3 sperm were also higher in the semen samples of both trisomic boars than in the control, although the differences were not statistically significant. Such results could be explained by the occurrence of interchromosomal effects in the spermatozoa of the trisomy 18 mosaic carriers [26]. Fluorescent in situ hybridization of probes specific for other chromosomes should be carried out to investigate this point.…”