Objective: To assess the prevalences of maturity onset diabetes of the young 2 (MODY2) in Chinese early onset familial type 2 diabetic population and explore the possibility of some common DNA variants of MODY2 gene to contribute to the susceptibility of type 2 diabetes in Chinese population.
Methods: A total of 100 early onset type 2 diabetes pedigrees in Beijing were collected. By PCR, all the exons and exon/intron splice sites of MODY2 gene were amplified, and PCR products were sequenced to identify the DNA variants . The SNPs were genotyped by homogenous mass extend (hME) assay in nonjdiabetic control population.
Results: Three DNA vatiants in MODY2 gene were identified: one in exon4(ccc-->ccg, heterozygous silent mutation,pro145pro), one in exon7(gcc-->gcg, heterozygous silent mutation, ala233ala), and one in intron 9 (IVS9+8 C>T). The prevalences of these variant alleles were 0.5 in exon 4, 0.5% in exon 7 and 36% in intron 9. An association study was conducted to examine the relationship between the IVS9+8 C>T polymorphism and early onset familial type 2 diabetes, the frequency of allele T of early onset familial type 2 diabetes population was significantly lower, and the frequency of allele C significantly higher, than those of control subjects (P<0.05).
Conclusion: Our research suggested in Chinese population the prevalences of MODY2 was less than 1% in early onset familial type 2 diabetic patients, the IVS9+8 C>T polymorphism at MODY2 gene, intron 9 or nearby genes was associated with early onset familial type 2 diabetes .