The overexpression of CaMKIIδC (as occurs in HF) by itself led to significant nuclear export of HDAC4 (FNuc/FCyto decreased from 1 ± 0.02, n = 84 to 0.83 ± 0.02, n = 70; Fig. 5a), consistent with a substantial increase in the basal CaMKII-dependent nuclear export. Here, CAMK2G is linked to hydrops fetalis.