Association between LTA, TNF and AGER polymorphisms and late diabetic complications

Abstract

Background: Several candidate on the short arm of chromosome 6 including the HLA locus, TNF, LTA and AGER could be associated with late diabetic complications. The aim of our study was therefore to explore whether polymorphisms (TNF-308 G→A, LTA T60N C→A and AGER -374 T→A) in these genes alone or together (as haplotypes) increased the risk for diabetic complications. Methodology/Principal Findings: The studied polymorphisms were genotype in 742 type 1 and 2957 type 2 diabetic patients as well as in 206 non-diabetic control subjects. The Haploview program was used to analyze putative linkage disequillibrium between studied polymorphisms. The TNF, LTA and AGER polymorphisms were associated with the HLA-DQB1 risk genotypes. The AGER -374 A allele was more common in type 1 diabetic patients with than without diabetic nephropathy (31.2 vs. 28.4%, p=0.007). In a logistic regression analysis, the LTA but not the AGER polymorphism was associated with diabetic nephropathy (OR 2.55 [1.11-5.86], p=0.03). The AGER -374 A allele was associated with increased risk of sight threatening retinopathy in type 2 diabetic patients (1.65[1.11-2.45], p=0.01) and also with increased risk for mascrovascular disease in type 1 diabetic patients (OR 2.05[1.19-3.54], p=0.01), but with decrease risk fpr macrovascular disease in type 2 diabetic patients (OR 0.66[0.49-0.90], p=0.009). The TNF A allele was associated with increased risk for mascrovascular complications in type 2 (OR 1.53 [1.04-2.25] p=0.03.but not type 1 diabetic patients. Conclusions/Significance: The association between diabetic complications and LTA, TNF and AGER polymorphisms is complex, with partly different alleles conferring susceptibility in type 1 and type 2 diabetic patients. We can not exclude the possibility that the genes are part of a large haplotype block that also includes HLA-DQB1 risk genotypes. © 2008 Lindholm et al.