<b>Background/Objectives:</b> Chronic kidney disease-mineral and bone disorder (CKD-MBD) is characterized by complex interactions between parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), phosphate, calcium, and vitamin D, yet clinical decisions are often based on static individual values. Here, FGF23 is linked to Marchiafava-Bignami disease.