Klinisches Outcome nach assistierter Reproduktionstherapie (ART) und Preimplantation Genetic Testing for Structural Rearrangements (PGT-SR) bei reziproker und Robertson-Translokation: Eine retrospektive, multizentrische Studie

Structural chromosome aberrations include, in addition to inversions and duplications of chromosome segments, translocations. Carriers of balanced translocations are generally healthy but bear elevated risks of miscarriage or a higher probability of producing offspring with severe malformations and developmental disorders due to unbalanced translocations. In vitro fertilization (IVF) with subsequent pre-implantation genetic testing for chromosomal structural rearrangements (PGT-SR) might offer a therapeutic option. However, there is no clear consensus on the benefits and effectiveness of PGT-SR. The problem arises not only from the heterogeneity and small number of cases in existing studies and the lack of large comparative or randomized controlled studies, but also from the ongoing technical development of prenatal diagnostics. While PGT was limited to polar body or blastomere biopsy and fluorescence in situ hybridization (FISH) analysis at the beginning of the millennium, trophectoderm biopsy and next-generation sequencing (NGS) now represent the gold standard. In addition to its high sequencing capacity, NGS enables high diagnostic sensitivity. This, however, allows the detection of more numerical and structural chromosomal aberrations in a chromosomal mosaic constitution—the presence of at least two different cell lines with different karyotypes. Consequently, this lowers the yield of embryos with a normal chromosomal constitution. The key question of this retrospective multicenter study was therefore: how many oocytes or blastocysts, respectively, are required in the context of preimplantation genetic diagnosis (PGD/PGT-SR) using an NGS platform in couples with known translocations to ensure the transfer of a potentially euploid or chromosomally balanced embryo.