For example, the formation of t-tubules and dyads coincides with the expression of JPH2 during development (Ziman et al., 2010), and knockdown of JPH2 during development inhibits t-tubule maturation (Reynolds et al., 2013), but in HF some groups have reported JPH2 expression is downregulated in a regression towards an immature phenotype (Minamisawa et al., 2004; Landstrom et al., 2007; Wei et al., 2010; Zhang et al., 2013; Guo et al., 2015). Here, JPH2 is linked to hydrops fetalis.