The isolated SR vesicles, from JTV519 treated animals, showed no abnormal Ca2+ leak, which was characteristic of HF in this model, and this was attributed to the lack of RyR2 hyperphosphorylation and the restitution of FKBP12.6 binding to levels seen in pre-paced hearts (Yano et al., 2003). The gene discussed is FKBP1B; the disease is hydrops fetalis.