Mapping allele with resolved carrier status of Robertsonian and reciprocal translocation in human preimplantation embryos.

Reciprocal translocations (RecT) and Robertsonian translocations (RobT) are among the most common chromosomal abnormalities that cause infertility and birth defects. Preimplantation genetic testing for aneuploidy using comprehensive chromosome screening for in vitro fertilization enables embryo selection with balanced chromosomal ploidy; however, it is normally unable to determine whether an embryo is a translocation carrier. Here we report a method named "Mapping Allele with Resolved Carrier Status" (MaReCs), which enables chromosomal ploidy screening and resolution of the translocation carrier status of the same embryo. We performed MaReCs on 108 embryos, of which 96 were from 13 RecT carriers and 12 were from three RobT carriers. Thirteen of the sixteen patients had at least one diploid embryo. We have confirmed the accuracy of our carrier status determination in amniotic fluid karyotyping of seven cases as well as in the live birth we have thus far. Therefore, MaReCs accurately enables the selection of translocation-free embryos from patients carrying chromosomal translocations. We expect MaReCs will help reduce the propagation of RecT/RobT in the human population.