engleski

Quantitative analysis of constitutive heterochromatin in couples with fetal wastage

Heteromorphism of constitutive heterochromatin is stable evolutionary feature, largely accepted to cause no phenotypic alterations. Nevertheless, the role of constitutive heterochromatin is still unknown. Instability of constitutive heterochromatin was observed restricted mainly to T-lymphocytes and connected to variable immunodeficiency. The functional role of heterochromatin region of chromosomes 1, 9, 16 and y in the immune response has been proposed as well as during early embryo development. In order to investigate a possible influence of constitutive heterochromatin in human reproductive ability, quantitative analysis of constitutive heterochromatin in human chromosomes 1, 9, 16, and Y was made. Thirty examined couples were divided into two groups owing to the clinical heterogeneity of their reproductive disorders. The first group included couples with two or more spontaneous abortions as the only pregnancy outcomes, and the second group included couples with a stillborn or stillborn malformed child. In the control group were couples with one or more healthy children without a history of fetal wastage. All examined persons had normal karyotype. The amount of constitutive heterochromatin was expressed by relative value using the simple transformation [q/(p+q)]. This value, obtained on GTG-banded metaphase chromosomes, represented an indirect measure of heterochromatin content. The Y/F index was used to express the relative amount of heterochromatin in chromosome Y. The results revealed significant increase in the heterochromatin content of homologue pair 16 in couples with stillborn or stillborn malformed child (p<0.01) as well as of the total heterochromatin cell content compared to a control (p=0.005). The same couples had significantly increased mean maximal heterochromatin content in the potential zygotes (p<0.02), while those who experienced spontaneous abortions only, had significantly increased minimal total heterochromatin content in the potential zygotes (p<0.05). The Y/F index was significantly lower in both groups of men compared to a control (p1<0.02 ; p2<0.02). The implication of our findings to huiman reproductive ability is discussed. The quantitative analysis of constitutive heterochromatin could be valuable in relation to immunological status of couples.

abortion; spontaneous; heterochromatin

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