Significance of chromosomal aberrations for the unsuccessful procedures of assisted reproduction.

Lymphocyte cultures from patients who had previously undergone at least three unsuccessful procedures of assisted reproduction were analysed for cytogenetic abnormalities. A total of 12,657 metaphases from 33 individuals (15 patients and 18 healthy controls with two normal offsprings) were studied. A significantly higher incidence (P<0.001) of chromosome aberrations was found in the patients (6.79+/-0.68%; x+/-SD) as compared to the controls (1.72+/-0.3%; P<0.001). Chromosomal breakages, particularly at the centromere region, were also observed with significantly increased frequency in the patients than in the controls (6.18+/-0.65 vs. 1.42+/-0.27%, respectively; P<0.001). It is possible that the high rate of centromere breakages in the ART patients (3.18+/-0.47 vs. 0.26+/-0.12%, P<0.001) may predispose to meiotic chromosomal abnormalities. A single cell aberration was demonstrated in 0.61+/-0.21% of ART patients' lymphocytes versus 0.3+/-0.12% in the controls (P<0.01). Structural rearrangements and chromosomal breaks predominantly affected the bands containing genes for the immune response and the cell cycle. Mosaic karyotypes were found in six patients. One of them had a karyotype 46,XX/46,XX,r(14) and the others had sex chromosomal mosaicisms. The prenatal diagnosis could be essential in these cases. It is concluded that chromosomal aberrations could play a role in the repeated failure of ART procedures.