Genetic association of type 1 diabetes in an Azerbaijanian population: the HLA-DQ, -DRB1*04, the insulin gene, and CTLA4.

BACKGROUND: Little is known on the genetic susceptibility to type 1 diabetes mellitus (T1DM) in the nations of the former Soviet part of south-west Asia. OBJECTIVE: The aim of the study was to characterize the genetic association of T1DM in the Azeri, the majority population of Azerbaijan. SUBJECTS AND METHODS: One hundred and sixty patients with childhood-onset T1DM, and 271 healthy unrelated controls were compared in a case-control study. All declared themselves as Azeri. The human leukocyte antigen (HLA)-DQB1, -DQA1 alelles, of DRB1*04 subtypes, and of insulin gene and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) single nucleotide polymorphisms were determined using polymerase chain reaction (PCR) techniques, the association was tested from cross-tabulations, and quantified using odds ratios (OR). In the non-HLA factors, analyses were also stratified according to the HLA-conferred risk. RESULTS: Risk for T1DM was associated with presence of the HLA-DQB1*02-DQA1*05, OR = 6.6 [95% confidence interval (CI) 4.3-10], the HLA-DQB1*0302-DQA1*03, OR = 3.9 (95% CI 2.6-6.0), and an unexpectedly high risk was observed for DQB1*0304, OR = 10.9, but the very wide CI (CI 95% 2.4-49) prompts careful interpretation. A negative association with diabetes was observed for the DQB1*0602, 0503, 0301, and 0601 alleles, as well as the DRB1*0403 subtype. A strong protection was also associated with the less frequent variant of the insulin gene (OR of the phenotypic positivity was 0.28, CI 95% 0.17-0.46), while the CTLA4 +49 A/G transition was not associated with T1DM. CONCLUSIONS: We bring the first report on both HLA, and non-HLA association of T1DM from the majority Azeri population of Azerbaijan.

Association of single nucleotide polymorphisms within cytokine genes with juvenile idiopathic arthritis in the Czech population.

OBJECTIVE: To examine the possible association of juvenile idiopathic arthritis (JIA) with polymorphisms within cytokine genes in the Czech population. METHODS: In a case-control study, genotypes of 130 patients with JIA (63 male, 67 female; age at onset 7.6 +/- 4.4 yrs; 43 oligoarticular, 72 polyarticular, 15 systemic form) were compared to 102 healthy unrelated blood donors. Using the polymerase chain reaction technique with sequence-specific primers from the 13th IHWG workshop, we analyzed 19 single nucleotide polymorphisms within 12 different cytokine genes [interleukin (IL)-1a, IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12, transforming growth factor (TGF)-beta, interferon (IFN)-g], and related molecules (IL-1R, IL-1RA, IL-4Ra). Genotype frequencies were compared using chi-square analysis, and the significance level was corrected for the number of independent tests. RESULTS: Significant positive association was found for the G allele of the IL-4 -1098 T/G polymorphism, which was carried by 10% of cases and 25% of controls [odds ratio (OR) 0.32, 95% confidence interval (CI) 0.16-0.67, corrected p = 0.038). Also, a nonsignificant increase in the frequency of the IL-1beta +3962 C allele was detected in cases (96%) versus controls (84%) (OR 4.65, 95% CI 1.64-13.2, corrected p = 0.091). We did not replicate previously found associations with the IL-1a, IL-6, IL-10, and IL-1RA polymorphisms. CONCLUSION: Our study showed association with JIA for the IL-4 -1098 T/G polymorphism. It also underlines the genetic contribution of IL-1 polymorphisms to the pathogenesis of JIA, as another polymorphism within the IL-1beta may influence the risk of the disease.

NEUROD polymorphism Ala45Thr is associated with Type 1 diabetes mellitus in Czech children.

Association of the NEUROD Ala45Thr polymorphism with Type 1 diabetes mellitus (DM) has been found in some but not all populations. We performed a study on the association of two NEUROD exon 2 polymorphisms, the Ala45Thr and the Pro197His, with childhood-onset Type 1 DM in the Czech population. We compared 285 children with Type 1 DM diagnosed under the age of 15 years with 289 non-diabetic control children. The genotypes were determined using novel real-time allele-specific PCR assays in the TaqMan format, and data were analysed using logistic regression. The numbers of subjects with codon 45 genotypes Ala/Ala, Ala/Thr, Thr/Thr were 95, 145, 45 among cases and 117, 130, 42 among controls. Thr45 phenotypic positivity was associated with a significant risk of Type 1 DM (OR=2.01, CI 95% 1.25-3.24) in a multivariate logistic regression model involving also the insulin gene -23HphI genotype and the presence of Type 1 DM-associated HLA-DQB1*0302-DQA1*03 (DQ8) and DQB1*0201-DQA1*05 (DQ2) molecules. No association was observed for the Pro197His mutation which was carried by 5.3% cases and 5.9% controls. Our results confirm that the NEUROD Ala45Thr polymorphism is associated with childhood-onset Type 1 DM.