We conclude that the simultaneous presence of the minor allele at rs1501899 and Arg990Gly may amplify the kidney stone risk in PHPT patients, despite their apparently opposite effects on CASR function in the kidney.
In PHPT patients, only R990G polymorphism was associated with disease parameters; in comparison with R/R, R/G+G/G patients showed lower mean serum parathyroid hormone (PTH) and phosphate levels (139.9 +/- 62.2 vs 199.9 +/- 136.3 pg/ml, P < 0.05 and 0.69 +/- 0.12 vs 0.81 +/- 0.18 mmol/l, P = 0.031 respectively), higher mean 24-h urine calcium concentration and calcium excretion (9.05 +/- 2.05 vs 6.77 +/- 4.31 mmol/24 h, P = 0.012 and 67 +/- 20 vs 51 +/- 26 mumol/l GF, P = 0.039), and increased prevalence of nephrolithiasis (90.0 vs 44.2%, P = 0.007).