Association of Levels of Mannose-Binding Lectin and the <i>MBL2</i> Gene with Type 2 Diabetes and Diabetic Nephropathy

<div><p>Objective</p><p>To investigate the association of Mannose-binding lectin (<i>MBL</i>) and the <i>MBL2</i> gene with type 2 diabetes and diabetic nephropathy and the influence of <i>MBL2</i> polymorphisms on serum <i>MBL</i> levels.</p><p>Methods</p><p>The study population included 675 type 2 diabetic patients with or without nephropathy and 855 normoglycemic controls. The single nucleotide polymorphisms (SNPs) of rs1800450, rs1800451, and rs11003125 of the <i>MBL2</i> gene were determined by the Multiplex Snapshot method. Serum <i>MBL</i> levels were measured by enzyme-linked immune sorbent assay.</p><p>Results</p><p>Rs1800450 and rs11003125 SNPs demonstrated strong linkage disequilibrium in the study population (r² = 0.97). The haplotypes constructed from the G allele of rs1800450 and the C allele of rs11003125 increased the risk for type 2 diabetes (<i>OR</i> = 1.2, 95% <i>CI</i> = 1.1–1.4, <i>P = </i>0.01). For rs1800450, GG and GA genotypes were associated with type 2 diabetes (<i>P = </i>0.02, 0.01, respectively). For rs11003125, the GC genotype frequency was significantly different between patients and controls (18.1% vs. 24.9%, <i>P = </i>0.001). Analyses of genotypes and allele frequency distributions among patients with normal UAE, microalbuminuria, and macroalbuminuria showed that there was no obvious evidence of association between the <i>MBL2</i> gene and diabetic nephropathy. Subjects with the GG genotype of rs1800450 and the CC genotype of rs11003125 had much higher serum <i>MBL</i> levels.</p><p>Conclusions</p><p>The rs1800450 and rs11003125 SNPs of the <i>MBL2</i> gene have strong linkage disequilibrium and are associated with type 2 diabetes in the North Chinese Han population. No association was observed between the <i>MBL2</i> gene and diabetic nephropathy. Subjects with the GG genotype of rs1800450 and the CC genotype of rs11003125 had much higher serum MBL levels. An association between elevated serum <i>MBL</i> and diabetic nephropathy was also observed.</p>