These have been identified to be reduced in HF previously, particularly the cardiac isoform of ATP2A2/SERCA2 wherein its affinity to Ca2+ and its expression were reduced (Abe et al, 2002; Arai et al, 1993; Flesch et al, 1996; Lipskaia et al, 2014; Muslimova et al, 2020; Ohkusa et al, 1997; Studer et al, 1994; Vangheluwe et al, 2007; Vetter et al, 2002). Here, ATP2A2 is linked to hydrops fetalis.