Preimplantation genetic diagnosis for couples with a Robertsonian translocation: practical information for genetic counseling

To evaluate the proportions of abnormal and normal embryos detected by preimplantation genetic diagnosis (PGD) of infertile couples of whom one was a Robertsonian translocation (RT) carrier, and to provide practical information, including details of reproductive outcomes, to aid in genetic counseling of such couples. We retrospectively analyzed all PGD cycles conducted to deal with RT at our center between January 2000 and December 2009. Subject demographic and clinical data were compared with the results of PGD. Employing PGD, we conducted a total of 66 cycles on 34 couples of whom one was an RT carrier, including 24 female and 10 male carriers. Of the 514 blastomeres tested, 161 (31.3%) were normal or balanced. Of the 57 cycles that included embryo transfer, 17 (29.8%) attained positivity for human chorionic gonadotropin (hCG). A total of 17 embryos were implanted and 16 babies, including two sets of twins, were born. The takehome baby rate was 41.2% per couple and the loss rate 6.6%. Receiver operating characteristic curve analysis showed that the proportion of alternate embryos associated with a sensitivity of 70.6% for prediction of clinical pregnancy following PGD was 0.31. Sex of the carrier and type of translocation were not significantly associated with pregnancy outcomes. Couples with RT may benefit from PGD; pregnancy success rate is improved and embryo loss reduced. We found that about 30% of embryos were of normal or balanced chromosomal constitution and that the percentage of normal or balanced embryos was predictive of PGD outcome.