PTH and Marchiafava-Bignami disease: Furthermore, among the variables associated with MBD and thymic atrophy, serum level of PTH and corrected calcium correlated negatively and positively, respectively, with both RTE and RTE% (PTH-RTE: r = −0.36, P < 0.001; PTH-RTE%: r = −0.21, P = 0.019; Calcium-RTE: r = 0.27, P = 0.002; Calcium-RTE%: r = 0.18, P = 0.045), whereas serum ALP level was correlated negatively with RTE (r = −0.20, P = 0.023).