Characteristics of the calcitriol-driven hypercalcemic syndrome include serum 25(OH)D concentration over 150 ng/L (over 375 nmol/L) associated with hypercalcemia (raised serum ionized calcium), hypercalciuria (urinary calcium, exceeding 400 mg/24 h), and suppressed parathyroid hormone (PTH) concentration [6]. The gene discussed is PTH; the disease is hypercalcemia disease.