Haplotype-based noninvasive prenatal diagnosis of methylmalonic acidemia and the discovery of a recurrent pathogenic haplotype associated with c.609G>A.

NIPD-MMA presents a viable choice for early, accurate, and safe prenatal diagnosis. Furthermore, the discovery of the recurrent core pathogenic haplotype provides a novel approach for haplotype phasing and has the potential for realizing proband-independent NIPD in the future.