TLX2 and hydrops fetalis: The proteins involved in Ca2+ handling, including the L-type voltage-dependent Ca2+ channel alpha 1C subunit (Cav1.2), SR Ca2+ ATPase (SERCA2a), and sodium-calcium exchanger (NCX), are essential for Ca2+ homeostasis and represent potential targets for HF therapy (Hasenfuss and Pieske, 2002; Gorski et al., 2015).