Noninvasive prenatal diagnosis for Duchenne muscular dystrophy based on the direct haplotype phasing

We aimed to investigate the validity of noninvasive prenatal diagnosis (NIPD) based on direct haplotype phasing without the proband or other family members and its feasibility for clinical application in the case of Duchenne muscular dystrophy (DMD).Thirteen singleton-pregnancy families affected by DMD were recruited. The pathogenic variants in the pregnant females have been identified by multiplex ligation-dependent probe amplification (MLPA). We resolved maternal haplotypes for each family by performing targeted linked-read sequencing of their high molecular weight DNA, respectively. Then, we integrated the maternal haplotypes and the targeted sequencing results of maternal plasma DNA to infer the fetal haplotype and the DMD gene variant status. The fetal genotypes were further validated by using chorionic villus sampling.The method of directly resolving maternal haplotype through targeted linked-read sequencing was smoothly performed in 12 participated families, but one failed (F11). The predicted variant status of 12 fetuses was correct, which had been confirmed by invasive prenatal diagnosis.Direct haplotyping of NIPD based on linked-read sequencing for DMD is accurate.