NPHPT: normocalcemic primary hyperparathyroidism; HPHPT: hypercalcemic primary hyperparathyroidism; SD: standard deviation; IQR: interquartile range; PTH: parathyroid hormone; PFi: parathyroid function index; 25(OH)D: 25-hydroxyvitamin D; *: statistically significant; **: highly statistically significant. The gene discussed is PTH; the disease is primary hyperparathyroidism.