SLC5A2 and Marchiafava-Bignami disease: This review summarizes the basic and clinical studies demonstrating (1) the key actions of Mg in CKD-MBD, including secondary hyperparathyroidism and bone abnormalities; (2) the distinctive profile of KT patients for Mg homeostasis; and (3) the interaction between commonly used drugs, such as SGLT2 inhibitors or immunosuppressive treatments, and Mg metabolism, providing a broad understanding of both the key role of Mg in the context of CKD and the treatments that should be considered to manage Mg levels in CKD patients.