Clinical application of an NGS-based method in the preimplantation genetic testing for Duchenne muscular dystrophy

Purpose To determine whether next-generation sequencing (NGS) could be used to directly detect different mutations of Duchenne muscular dystrophy (DMD) during preimplantation genetic testing (PGT). Methods From Sep. 2016 to Aug. 2018, a total of six couples participated in this study. Four cases carried DMD exon deletions and two carried exon duplications. Trophectoderm cells were biopsied at day 5 or 6 and NGS was used in the genetic testing of the biopsied cells after whole-genome amplification. We developed a new method-DIRected Embryonic Cell Testing of Exon Deletion/Duplication (DIRECTED) to directly detect the single-gene mutation by NGS. Linage analysis based on single-nucleotide polymorphism (SNP) was used to validate the results from DIRECTED. Results In the four deletion cases, DIRECTED was used to detect DMD exon deletion in 16 biopsied embryos. All DIRECTED results were consistent with linkage analysis, indicating this method was reliable in detecting deletions around 1 Mb. In the two cases carrying exon duplications, no blastocyst was obtained for biopsy. Nonetheless, preliminary experiment results suggested that DIRECTED could also be used for direct detection of exon duplications in embryos. Conclusions Exon deletions or duplications in DMD of preimplantation embryos could be detected directly by NGS-based methods during PGT.