[Association of calcium-sensing receptor gene polymorphism with serum calcium level in healthy young Han women in Beijing].

Objective: To investigate the distribution of calcium-sensing receptor (CASR) gene polymorphisms in healthy young women of Han nationality in Beijing area and to explore the association of CASR genotypes and serum calcium, parathormone (PTH) level in healthy women.

Methods: 202 healthy young women aged (27 +/- 5) years of Han nationality in Beijing area were recruited in this study. Whole blood genome DNA was extracted with QIAGEN DNA extraction kit. A986S and G990R genotypes were determined with mutagenically separated polymerase chain reaction (MS-PCR) and PCR-restriction fragment length polymorphisms (RFLP), respectively. Serum calcium, albumin, phosphorus, PTH were determined.

Results: (1) There were A986S and G990R polymorphisms in healthy young women of Han nationality in Beijing. The frequencies of genotypes were as follows: SS absent, AA 95.0% and AS 5.0% for A986S, RR21.3%, GR51.0% and GG27.7% for G990R. Hardy-Weinberg equilibrium was evident. (2) In subjects carrying AA and AS genotype, serum Ca was (2.46 +/- 0.09) mmol/L vs (2.45 +/- 0.08) mmol/L, calcium adjusted by albumin was (2.31 +/- 0.10) mmol/L vs (2.30 +/- 0.09) mmol/L, serum P was (1.23 +/- 0.14) mmol/L vs (1.24 +/- 0.11) mmol/L, serum PTH was (41.6 +/- 18.6) ng/L vs (50.0 +/- 25.1) ng/L. There were no significant differences among them. (3) In subjects carrying GG, GR and RR genotype, serum Ca was (2.44 +/- 0.10), (2.46 +/- 0.08) and (2.48 +/- 0.08) mmol/L; calcium adjusted by albumin was (2.30 +/- 0.10), (2.32 +/- 0.09) and (2.32 +/- 0.10) mmol/L; serum P was (1.22 +/- 0.13), (1.24 +/- 0.15) and (1.20 +/- 0.15) mmol/L, serum PTH was (37.6 +/- 16.0), (42.1 +/- 20.2) and (45.9 +/- 18.1) ng/L. There were significant difference in serum Ca, calcium adjusted by albumin and PTH (P = 0.042, 0.020 and 0.014, respectively).

Conclusions: (1) There are A986S and G990R polymorphisms in CASR gene in Han nationality in Beijing area. The frequencies of genotypes are as follows: SS absent, AA 95.0% and AS 5.0% for A986S, RR21.3%, GR51.0% and GG27.7% for G990R. Hardy-Weinberg equilibrium is evident. A and G alleles are more common. It is indicated that the distribution of CASR gene polymorphisms in Chinese is different from that in Caucasians. (2) G990R polymorphism is associated with serum calcium and PTH levels in healthy women. Subjects with R allele have higher levels of serum calcium and PTH. There is no correlation between A986S polymorphism and serum calcium or PTH.