Chromosome heteromorphisms and early recurrent abortions.

In order to identify the role played by heterochromatic polymorphisms in miscarriage, an analysis was carried out on 257 couples, 137 of them with two or more abortions and 120 serving as a control. All couples were taken from two Italian populations: 77 cases and 70 controls came from an exogamic population whilst 60 cases and 50 controls came from an almost endogamic one. Out of the 137 cases, six couples in the exogamic and five in the endogamic groups were excluded because at least one partner had balanced chromosomal aberrations. Four controls from the exogamic group were also excluded for the same reason. The remaining 126 cases were analysed to detect the presence of chromosomal heteromorphism in one or both partners. The results suggested that chromosomal heteromorphism does not induce miscarriage. In fact, only one heteromorphism, inv(9)(p11q12), seems to be marginally related to recurrent abortion and only in the exogamic population. In addition no differences were found in the distribution of chromosomal heteromorphism in the couples analysed in relation to the number of abortions, i.e. two or more than two.

Genetic polymorphisms and human reproduction: a study of phosphoglucomutase in spontaneous abortion.

Theoretical arguments suggest that variation of metabolic parameters due to genetically determined enzyme polymorphisms may exert important effects on implantation and zygote development. The polymorphic enzyme phosphoglucomutase controlled by locus 1 (PGM1) is a phosphotransferase which plays a key role in carbohydrate metabolism and it is present in high concentrations in placental tissue. The enzyme has been studied in 47 couples with habitual abortion, in 36 women with single episodes of spontaneous abortion, in 48 women with induced abortion, and in control samples of normal individuals from the same population. Among couples with habitual abortion a significant increase of mean survival time of fetuses was observed in PGM1-heterozygote mothers as compared to homozygotes. An increased proportion of couples which may produce the hypothetical PGM1-null phenotype was also observed in habitual abortion, which suggests that homozygosity for PGM10 allele may contribute to fetal loss. Investigations on polymorphic enzymes involved in placental and fetal metabolism may contribute significantly to the problem of genetic etiology of spontaneous abortion.