Microsatellite mutations in spontaneously aborted embryos

Abstract

Objective: To evaluate the incidence of microsatellite instability in spontaneously aborted embryos.

Design: Retrospective study.

Setting: Laboratory of Clinical Virology and Department of Obstetrics and Gynecology, University Hospital, Medical School, University of Crete.

Patient(s): Thirty-five women in whom spontaneous abortions occurred between the 6th and 20th weeks of pregnancy.

Intervention(s): Thirty-five aborted embryonic tissues were analyzed with seven microsatellite markers, and their haplotypes were compared with the corresponding pattern of their parents.

Main outcome measure(s): Microsatellite DNA.

Result(s): Microsatellite instability was observed in 8 of 35 cases (23%). In 7 of 8 positive cases, microsatellite instability was restricted to one of the seven microsatellite markers, whereas in one case, three microsatellite markers were affected by instability. A statistically significant association was found between microsatellite instability and a previous normal childbirth.

Conclusion(s): Genetic instability is a detectable phenomenon in spontaneous abortions, representing a significant increase in the mutational rate of the embryo and providing evidence for a mechanism associated with the phenomenon of spontaneous abortion. We conclude that this elevated mutational rate affects active genomic sequences that play a critical role in the viability of the embryo, leading to cell death and abortion.