S2), the proteomic profiles showed downregulation of CaSR and upregulation of GABAB1R in parathyroid tumors from vitamin D-deficient patients compared to vitamin D-replete patients and to normal controls, leading to a sharp elevation in the GABAB1R/CaSR ratio (Fig. 5A and fig. The gene discussed is CASR; the disease is tumor of parathyroid gland.