Mammalian Ste20‐like kinase (Mst) 1 is a serine‐threonine kinase and a component of the Hippo signalling pathway that has been shown to promote apoptosis and induce HF.18 Our previous studies suggested a potential role for Mst1 in regulating cardiomyocyte autophagy; moreover, Mst1 knockout protected cardiomyocytes against apoptosis in diabetic cardiomyopathy.19, 20 However, the effect of cardiac‐specific Mst1 knockout (Mst1Δ/Δ) in Ang II‐induced cardiac apoptosis and the underlying mechanisms are not well understood. The gene discussed is MST1; the disease is hydrops fetalis.