[Mutation screening of GCK gene in Chinese early-onset diabetes population]

To investigate the prevalence of mutations and sequence variations of glucokinase gene GCK in Chinese early-onset diabetes population.

The study was conducted in 174 unrelated Chinese residents, including 80 nondiabetic controls, 94 probands of early-onset diabetes pedigree. Direct sequencing was performed to screen all 10 exons of glucokinase gene, including promoter and exon/intron junctions.

No mutations were identified in coding region, but several previously reported sequence variants were identified. 5'-untranslated region of exon 1a, 84 bp upstream of the translation initiation site GGCGG to GGGGG(early-onset diabetes group G allele frequency 0.106 vs control group 0.075, P=0.355); IVS1b+12 (A-->T) (early-onset diabetes group T allele frequency 0.005 vs non-identity of this variation in control group); IVS 5+29 (G-->T) (early-onset diabetes group T allele frequency 0.027 vs control group 0.019, P=0.731); IVS 9+8 (T-->C) (early-onset diabetes group C allele frequency 0.585 vs 0.694, P=0.044). A novel variation IVS 9+49 (G-->A) (early-onset diabetes group A allele frequency 0.011 vs control 0.006, P=1.000) was identified. There were no significant relationships of the exon 1a 5'-untransted region -84 bp(C-->G), IVS 5+29 (G-->T), IVS 9+8 (T-->C) and IVS 9+49 (G-->A) variants of GCK gene to the clinical variables such as plasma glucose, insulin, C-peptide and fasting lipid profile.

The prevalence of structural mutations in glucokinase gene responsible for early-onset diabetes appears to be rare among Chinese patients.