Chromosomal breakpoints in aborters. A relationship with heritable fragile sites.

A literature survey has been conducted to estimate the incidence of breakpoints in aborters. Out of 9,012 cases that could be evaluated, about 4.0% had chromosomal abnormalities, which is significantly higher as compared to the normal population (1-0.5%). The structural anomalies were 7 times higher than numerical abnormalities. Thirty-seven percent of the rearrangements were in males while 63.0% were in females. Among all types of chromosomal aberrations, the Robertsonian types were most frequent (22.3%). However, no sex chromosomal abnormalities were found. Furthermore, the breakpoints on each chromosome were cumulated and no relationship with the relative length of chromosomes was observed. Nevertheless, 60.3% of the breakpoints were localized in G-negative areas of the human genome. The currently known heritable fragile sites were further correlated with the incidence of breakpoints in aborters. A significant relationship with heritable fragile sites was found in this study. Therefore, a family study including the abortus is suggested to establish the mode of inheritance, which possibly could be autosomal recessive. This approach in turn will provide new information to geneticists for counselling the subjects with recurrent fetal loss.