Allofthepatients andcontrols underwenta screeningevaluationthat included personal medical history, complete family history, and physical examination (e.g., body weight, body mass index and blood pressure).Blood and urinary biochemical tests were conducted including: total erum calcium (reference range: 2.00–2.75 mmol/L), phosphate (0.80–1.60 mmol/L), creatinine (53.0–115.0 umol/L), albumin (32–55 g/L), and totalserumalkalinephosphatase(AKP)(38–121 IU/L)(BeckmanCoulter,USA). Albumin-corrected serum calcium was calculated using the formula: [40 –(serum albumin(g/L)]×0.02 +serum calcium (mmol/L).Serum immunoreactive intact PTH was measured by an intact immunoradiometric assay (IRMA) (ABBOTT Diagnostics Division,USA; reference range, 15–65 pg/mL). Serum 25-hydroxyvitamin D[25(OH)D] concentration was measured by an enzyme immunoassay[Immunodiagnostic Systems, UK; physiologically normal range N20 ng/mL (50 nmol/L), assay reference range 17.88–57.6 ng/mL(44.7–144 nmol/L)].