PTH and Marchiafava-Bignami disease: Since bone turnover in CKD is a function in large part of the degree of secondary hyperparathyroidism (SHPT), circulating parathyroid hormone (PTH) levels together with serum calcium, phosphorus and total alkaline phosphatase (ALP) activity are used to diagnose bone turnover and to guide the pharmacologic treatment of CKD-MBD [4].