METTL3 and hydrops fetalis: Increased METTL3 expression regulates mitogen-activated protein kinase (MAPK) and intracellular signaling pathways and further mediates CM hypertrophy, whereas silencing of METTL3 prevents the ability of CM to hypertrophy [139] In heart failure (HF), m6A methylation and METTL3 expression are elevated.