Clinical outcomes of preimplantation genetic diagnosis (PGD) and analysis of meiotic segregation modes in reciprocal translocation carriers.

Balanced reciprocal translocation is the most common chromosome rearrangement, with an incidence of 1 out of 625 newborns. In reciprocal translocation carriers, genetically unbalanced gametes can be produced through three principal modes of segregation: adjacent-1, adjacent-2 and 3:1. In this study, we reviewed 133 cycles of preimplantation genetic diagnosis (PGD) for 65 couples with reciprocal translocation and analyzed pregnancy outcomes and the meiotic segregation mode of gametes of the translocation carriers using fluorescent in situ hybridization (FISH). We found that 285 of 1,508 embryos (18.9%) were normal or balanced. Thirty-three clinical pregnancies, including eight spontaneous abortions (21.6% per couple), were established. According to the meiotic segregation analysis, the frequencies of 3:1 and 4:0 segregation modes were significantly higher (P < 0.05) in female carriers, and the frequencies of adjacent-1 and chaotic segregation modes were significantly higher (P < 0.05) in male carriers. Our results indicate that meiotic segregation might be affected by the carrier's sex but not by the carrier's age or breakpoints.