Chronic kidney disease (CKD) is a very common disorder and is characterized by reduced expression of the FGF23 co-receptor αKlotho.20–23 This shift leads to increased FGF23 and drives the suppression of 1,25D and secondary hyperparathyroidism in CKD, causing severe bone disease. The gene discussed is FGF23; the disease is secondary hyperparathyroidism.