RÉSUMÉ
Objective To study the distribution of the G/A variant at position -30 of the glucokinase gene promoter in southern Chinese subjects with impaired glucose tolerance (IGT) and normal glucose tolerance (NGT) and to investigate the association between different genotypes and indices of glucose metabolism. Methods Four hundred and fourty four unrelated Chinese subjects 〔aged (50.8?12.2)years〕 without diabetics were studied, among them 222 subjects with NGT and 222 with IGT. The G to A substitution at position -30 of the glucokinase promoter, resulting in the loss of a BsiHKA Ⅰ cut site, was detected after BsiHKA Ⅰ digestion of PCR amplified genomic DNA. Results Allele frequency of the A variant was 18.2% in NGT (similar to finding in native Japanese) and 19.8% in IGT subjects. Fasting plasma glucose level was significantly higher in subjects with the A allele (n=153; GA:AA=137:16), when compared to the GG subjects (n=291), 〔(5.35?0.59 vs 5.19?0.53) mmol/L, P=0.006〕. Higherfastingglucoselevelwasalsofound when only IGT subjects with the A variant and GG allele were analyzed 〔(5.54?0.58 vs 5.35?0.52) mmol/L, P=0.02〕. In subjects with NGT, there was no significant difference in fasting plasma glucose levels between different GCK genotypes. Conclusion GCK gene promoter -30 G/A variant is associated with higher fasting plasma glucose levels, and may contributes to the development of IGT in Southern Chinese.