The smaller RyR clusters observed in failing cells were found to exclusively occur at dyadic sites (sham: 9.09 ± 0.47 vs. HF: 6.81 ± 0.44 RyRs/cluster), where dispersed RyR arrangements were again reversible by CaMKII or PKA inhibition (Figure 6g). The gene discussed is RYR2; the disease is hydrops fetalis.