Chromosome studies in 500 induced abortions

Abstract

A survey of the chromosome constitution in 500 induced abortions (5-12 menstrual weeks) was undertaken over a period of 1 1/2 years. There were 34 cases (6.8%) of gross chromosome anomalies: 2 cases of trisomy A; 5 of trisomy C (including XXX and XXY); 1 of mosaic trisomy C; 4 of trisomy D; 2 of trisomy E; 2 of trisomy G; 1 of double trisomy E and G; 1 of XYY; 4 of monosmy C (including XO); 2 of mosaic monosomy C; 1 of mosaicism of ring D chromosome; 1 of extra small metacentric chromosome; 3 of triploidy (including triploidy with double trisomy C and G); and 5 of tetraploidy and its mosaicism. An increased risk for the occurrence of trisomic anomalies was found with advancing age of the mothers. In contrast, the production of monosomies was not age-related. Trisomies were the most common type of anomalies and were found almost at random, regardless of the characteristics of chromosomes. Neither satellited nor small chromosomes were predominantly involved in the formation of chromosome anomalies.

PIP: The chromosome composition of 500 fetuses of 5-12 weeks gestation was analyzed postabortion. There was a total of 34 cases (6.8%) of gross chromosome abnormalities. There were 2 cases of trisomy A, 5 of trisomy C, 1 of mosaic trisomy C, 4 of trisomy D, 2 of trisomy E, 2 of trisomy G, 1 of double trisomy E and G, 1 of XXY, 4 of monosomy C, 2 of mosaic monosomy C, 1 of mosaicism of ring D chromosome, 1 of extra small metacentric chromosome, 3 of triploidy, and 5 of tetraploidy and its mosaicism. The risk of trisomic anomalies was greater with increasing maternal age. However, the occurrence of monosomes was not related to maternal age. Trisomies were virtually found at random, regardless of the chromosomal characteristics. Satellite clusters and smaller chromosomes were not markedly involved in the production of chromosome anomalies.