All patients had presurgical mild hypercalcemia with slightly elevated plasma ionized serum calcium levels (mean 1.47 mmol/L, range from 1.34 to 1.61 mmol/L; normal 1.18–1.32 mmol/L) and no parathyroid hormone suppression (presurgical PTH plasma concentration: mean 23.39 pmol/L, range from 5.55 to 76.00 pmol/L; normal 1.18–8.43 pmol/L). This evidence concerns the gene PTH and hypercalcemia disease.