TLX2 and hydrops fetalis: It is perplexing that the SR Ca2+ load increases during the evolution from NFTG to FTG, since ICa,L density does not increase, and Ca2+ efflux via NCX is augmented, it might be expected that mechanisms to reduce Ca2+ pumping into the SR might prevail: in many other HF models, SERCA2a becomes reduced, PLN increases, and its phosphorylation decreases [1], [7].