Indiscriminate FGF23 neutralization with monoclonal antibodies has been shown to worsen hyperphosphatemia, and increase vascular calcification and mortality in rat models of CKD.188, 189 Use of anti‐FGF23 monoclonal antibodies such as burosumab, currently approved for the treatment of x‐linked hypophosphatemia, causes severe side effects in patients with CKD by decreasing phosphaturia.190 Analogous to the use of calcimimetics, total blockade of FGF23 may theoretically be of benefit in ESRD. The gene discussed is FGF23; the disease is hyperphosphatemia.