The biochemical profile of PHPT is classically characterized by elevated serum intact parathyroid hormone (PTH) levels coupled with hypercalcemia and slight or mild hypophosphatemia (with or without hypercalciuria).1, 3 Thus, the diagnosis of PHPT is based on the combination of hypercalcemia and elevated PTH.3 However, not all PHPT patients exhibit this biochemical pattern. This evidence concerns the gene PTH and Hypercalciuria.