Loss of chromosome fragments or whole chromosomes in fibroblasts of extraembryonic mesoderm of spontaneous abortions with aneuploidy and triploidy

Numerical chromosome abnormalities are the most significant genetic failures. It is known that chromosomal aneuploidy may cause instability in tumor cells. However, it remains unknown whether the presence of numerical chromosome abnormalities in cell leads to the induction of chromosomal instability in embryogenesis. Goal. This work aims to identify the impact of numerical chromosome abnormalities on the frequencies of chromosome fragment and whole chromosome loss in fibroblasts of extraembryonic mesoderm of I trimester spontaneous abortions. Materials and methods. The frequencies of centromere-negative micronuclei containing the chromosome fragments, and centromere-positive micronuclei formed around the whole lagging chromosomes, were assessed in fibroblasts of extraembryonic mesoderm of 21 spontaneous abortions with different karyotypes (9 abortions with normal karyotype, 7 abortions with aneuploidy, and 5 triploid abortions). Nineteen induced abortions were used as a control group. Results. Despite the increased frequency of chromosome loss in the subgroup of spontaneous abortions with aneuploidy compared with spontaneous abortions with normal karyotype and induced abortions, significant differences were not found. Conclusions. Presence of aneuploidy is not enough for induction of chromosome instability in human cells indicating the existence of mechanisms of genome stability maintenance in the extraembryonic tissues, which are non-sensitive to aneuploidy and polyploidy.

анеуплоидия, хромосомное отставание, микроядерный тест, FISH, экстраэмбриональная мезодерма, aneuploidy, chromosome loss, micronucleus test, FISH, extraembryonic mesoderm

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