The lack of X-linked promoter DNAme in extraembryonic mesoderm-derived cells (endothelial/stromal) is consistent with a distinct developmental origin of these populations relative to the other placental and umbilical cell types. Autosomal DNAme also showed cell-type differences in alignment with cellular relationships observed for sex chromosomes. This work suggests the effects of sex chromosome complement on pregnancy outcomes may differ by placental cell type.
Han et al. (2026) studied this question.