TLX2 and hydrops fetalis: Our results support a tight association between NCX overexpression (Figure 4B) and the acceleration in the caffeine Ca2+ transient decay (Figure 2D), which could lead, at least in part, to the decrease in the amplitude of twitch and caffeine Ca2+ transients at the cellular level (Figure 2A and B) and the appearance of HF signs in the intact animal (Figure 1D and E).