FGF23 and Friedreich ataxia: ERRγ regulates hepatic fibroblast growth factor 23 (FGF23), an endocrine hormone primarily secreted by osteocytes and osteoblasts, but also induced in hepatocytes in response to folic acid induced acute kidney injury (FA-AKI) and carbon tetrachloride (CCl4) mediated acute liver injury (CCl4-ALI) [24,25].