Association Study Of Single Nucleotide Polymorphisms (Snps) Of KCNJ11and Type2Diabetes Of Korean Chinese In Yanbian Area

BACKGROUND: Type2diabetes mellitus (T2DM) is a heterogeneous genetic disorder and complex disease, characterized mainly by elevated plasma glucose levels that result from insulin resistance and impaired insulin secretion in pancreatic beta cell. The pathogenesis is characterized mainly by the combination of many minor genes and environmental factors. Recently, according to Genome-Wide Association Studies (GWAS), the inwardly rectifying potassium channel, subfamily J, member11(KCNJ11) has been one of highly susceptibility genes to T2DM. Single nucleotide polymorphisms (SNPs) of KCNJ11gene was significantly relativity with insulin secretion and had difference in different countries and races. OBJECTIVE:This research was intended to explore the correlation between SNPs of KCNJ11gene and T2DM in Korean minority of Yanbian area. METHOD:This research was divided into two parts:1. We obtained the full-length sequence and SNPs of KCNJ11gene in dbSNP and HapMapG database of NCBI by bioinformatic approaches. We designed4PCR primers and amplified4DNA fragments including the whole exon,5’UTR and3’UTR. The first stage experiment checked106patients of Korean minority and divided into two groups:55T2DM patients for case group and51healthy people for control group. Capillary electrophoresis (CE) technology carried out the whole KCNJ11gene sequencing. We screened out Minor allele frequency Count (MAF) and determined suspected SNPs of T2DM by analyzing the association of allele frequency, genotype frequency between case group and control group.2. We tested suspected SNPs of large sample by Multiplex-SNaPshot technology and analyzed the association between case group and control group. RESULTS:The first stage experiment results:1. Genome-wide sequencing:(1) We were for the first time to conduct KCNJ11gene sequencing to Korean Chinese and screened out10SNPs:5’UTR:-506-T, rs35513985; cSNP:E23K (G>A, rs5219), A190A C>T, rs5218), V337I (A>G, rs5215), I284I (C>A, rs1800854), L281L (C>T, rs116392938), R221C (C>T) and R365C (C<T);3’UTR:+62G>A (rs5213),+215C<T (rs5210); new discovered SNPs:R221C and R365C;(2) rs5219was strong linkage disequilibrium with rs5215(D’=0.980, r2=0.873), rs5219was weak linkage disequilibrium with rs5218(D’=0.973,r2=0.504), rs5213was perfect linkage disequilibrium with rs5219(D’=1.000,r2=1.000), rs5210was perfect linkage disequilibrium with rs5218(D’=1.000, r2=1.000);(3) We did not found any study on SNPs I284I and L281L in PubMed. But we interestingly discovered2heterozygote I284I (CA) in55T2DM group and none in control group. Genotype CA frequency was3.6%and allele A frequency was1.8%. We also discovered1heterozygote L281L (CT) in control group and none in case group. Genotype CT frequency was2.0%.2. Allele, genotype and haplotye:(1) There were no relativity between rs5219, rs5215and T2DM (P>0.05);(2) There was significant relativity between rs5218and T2DM:genotype CCvsCTvsTT was significant difference between case group and control group (X2=9.109, P=0.011), people with allele T (CT+TT) was more sensitivity to T2DM than people with CC[x2=3.373, P=0.053, OR=2.262,95%CI(1.981-5.215)];(3) Haplotype of rs5219, rs5218, rs5215was no relativity with T2DM (P>0.05);3. Genotype and clinical biochemistry indicator:(1) Allele G of rs5219had the trend of increasing BMI:AA=19.54±8.05, AG=23.96±4.18, GG=20.86±9.23, P=0.052;(2) Allele G of rs5219was the risk factor of decreasing insulin secretion: AA=55.73±10.75, AG=19.63±8.95, GG=30.75±27.51, P=0.005;(3) Allele G of rs5219was the risk factor of insulin resistance:AA=17.37±10.05, AG=5.51±4.09, GG=4.91±2.43, P=0.002;(4) Allele T of rs5218was the risk factor of increasing BMI: CC=20.07±7.86, CT=24.93±3.71, TT=0.34±9.74, P=0.045;4. Nation, race comparion:(1) rs5219of Korean Chinese was significant difference with CEU (P=0.044) and was highly significant difference with HCB, JPT, YRI (P<0.01);(2) rs5218of Korean Chinese was no difference with CEU, JPT (P>0.05), but was significant difference with HCB(P=0.034) and was highly significant difference with YRI (P<0.01);(3) rs5215of Korean Chinese was no difference with CEU (P>0.05), but was significant difference with HCB, JPT (P<0.05) and was highly significant difference with YRI (P<0.01);5. Clinical biochemistry indicator:FPG was positive correlation with LDL-C, HbA1C (R2=0.044、0.064), PA was inverse correlation with FPG, LDL-C, HbA1C (R2=0.077、0.095、0.002). Conclusion:1. We were for the first time to conduct KCNJ11genome-wide sequencing and screened out10SNPs.8SNPs were included in dbSNP database:rs35513985, E23K, A190A, V337I, I284I, L281L, rs5213, rs5210.2SNPs were new discovered:R221C and R365C;2. R221C may be the risk factor of T2DM in Korean Chinese and R365C was not;3. rs5218was significant relativity with T2DM. Genotype CC was advantage genotype and CT, TT were disadvantage genotype. Allele T was the risk factor of T2DM;4. rs5219was strong linkage disequilibrium with rs5215and weak linkage disequilibrium with rs5218, rs5213was perfect linkage disequilibrium with rs5219, rs5210was perfect linkage disequilibrium with rs5218;5. Allele G of E23K had the trend of increasing BMI and was the risk factor of insulin secretion and insulin resistance;6. KCNJ11gene SNPs had nation difference and race difference;7. PA was inverse correlation with FPG, LDL-C,; LDL-C was positive correlation with FPG.