Nanopore Sequencing IDs Euploid Embryos for Reciprocal Translocation Carrier Parents

For a paper appearing in BMC Genomics, researchers at Central South University in Hunan, China, and Yikon Genomics demonstrate that nanopore sequencing can pick up balanced reciprocal translocation (BRT) events in embryos from BRT carriers — findings that are expected to have applications for preimplantation genetic testing (PGT). Because such reciprocal chromosomal translocations have been implicated in everything from birth defects to infertility and miscarriage, the team says, BRT carrier parents frequently turn to PGT to identify euploid, typical karyotype embryos that will boost their odds of a successful, healthy birth. In two individuals carrying such translocations, the authors used nanopore sequencing to flag multiple embryos per patient that were euploid and did not carry the balanced translocations found in the patient, confirming these results with an existing sequencing-based "mapping allele with resolved carrier status" approach and by amniocentesis. "Our results suggest that nanopore sequencing is a powerful strategy for accurately distinguishing non-translocation embryos from translocation carrier embryos and precisely localizing translocation breakpoints," they write, "which is essential for PGT ad aids in reducing the propagation of reciprocal translocation in the population."