RYR2 and hydrops fetalis: Previous work has indicated that nanoscale RyR positioning is fine-tuned by phosphorylation of the channels, at least acutely (Asghari et al., 2014; Asghari et al., 2020), and that both Ca2+/calmodulin-dependent protein kinase II (CaMKII)- and protein kinase A (PKA)-dependent phosphorylation of RyR disrupt its function during HF (Ling et al., 2009; Marx et al., 2000; Zhang et al., 2003).