Faul et al. (2011) presented evidence that FGF23 can trigger cardiac hypertrophy in the context of klotho deficiency in vitro and in vivo, which was later confirmed in other studies (Leifheit-Nestler et al., 2016, 2018a; Böckmann et al., 2019; Schön et al., 2021). The gene discussed is KL; the disease is hyperinsulinemic hypoglycemia, familial, 4.