PTH and Marchiafava-Bignami disease: Chronic kidney disease–mineral bone disorder (CKD-MBD) currently has a broader definition, including: Abnormalities of calcium, phosphorus, PTH or vitamin D.; abnormalities in bone turnover, mineralization or strength [15]; and even isolated hyperphosphatemia or, in patients with calciphylaxia, serum PTH concentration above 500 mg/dl [16].