GSK3B and hydrops fetalis: It has been suggested that GSK3β is an endogenous negative regulator of cardiac hypertrophy, the activity of which is strictly controlled by its phosphorylation, and inhibition of Ser9 phosphorylation in GSK3β reduces cardiac hypertrophy and risk of HF (Hardt and Sadoshima, 2004; Matsuda et al., 2008).