Cardiac sodium-calcium exchanger (NCX) is an essential regulator of intracellular ion homeostasis, and studies have suggested that NCX activity is increased in HF and may contribute to impaired contractility by depleting the Ca2+ content in the sarcoplasmic reticulum (Studer et al., 1994; Flesch et al., 1996; Armoundas et al., 2007). Here, TLX2 is linked to hydrops fetalis.