Since the discovery in 1957 of a unique class of synthetic steroids, “spirolactones” which abolish aldosterone effects [9], several mineralocorticoid receptor blockers (MRBs) have been developed and proven to contribute to organ protection, particularly in heart failure (HF), diabetic kidney disease (DKD), and chronic kidney disease (CKD), beyond its antihypertensive effects [8, 10–12]. The gene discussed is NR3C2; the disease is hydrops fetalis.