PTH and Marchiafava-Bignami disease: Thus, CKD-MBD is a CKD-specific cardiovascular risk factor and displays changes in mineral metabolism parameters including phosphate, calcium, parathyroid hormone (PTH), calcitriol (1,25-dihydroxyvitamin D3, or 1,25D), and fibroblast growth factor 23 (FGF23) (10).