This is consistent with many studies that showed that FGF23 had been associated with lower eGFR and is the earliest analyte affected in mineral metabolism in CKD prior to vitamin D, iPTH, calcium, and phosphate [2,10,11]. Elevated FGF23 in CKD is primarily driven by phosphate accumulation and FGF23 resistance, both consequences of renal impairment. The gene discussed is FGF23; the disease is chronic kidney disease.