CDKN1A and hydrops fetalis: While the p21(Cip1) gene showed an increase in H3ac, H4ac and H3K4me2 and decreased H3K27me3 levels at the promoter and/or the coding region in OP mice compared to OR mice (Zhang et al., 2012), the same author in a later report found that p21(Cip1) is decreased in HF-treated mice compared to control, with no significant PTM changes (Zhang et al., 2018).