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- Mychaleckyj, Josyf C., et al.
(författare)
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HLA genotyping in the international Type 1 Diabetes Genetics Consortium
- 2010
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Ingår i: Clinical Trials. - : SAGE Publications. - 1740-7753 .- 1740-7745. ; 7:1 suppl., s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- Background Although human leukocyte antigen (HLA) DQ and DR loci appear to confer the strongest genetic risk for type 1 diabetes, more detailed information is required for other loci within the HLA region to understand causality and stratify additional risk factors. The Type 1 Diabetes Genetics Consortium (T1DGC) study design included high-resolution genotyping of HLA-A, B, C, DRB1, DQ, and DP loci in all affected sibling pair and trio families, and cases and controls, recruited from four networks worldwide, for analysis with clinical phenotypes and immunological markers. Purpose In this article, we present the operational strategy of training, classification, reporting, and quality control of HLA genotyping in four laboratories on three continents over nearly 5 years. Methods Methods to standardize HLA genotyping at eight loci included: central training and initial certification testing; the use of uniform reagents, protocols, instrumentation, and software versions; an automated data transfer; and the use of standardized nomenclature and allele databases. We implemented a rigorous and consistent quality control process, reinforced by repeated workshops, yearly meetings, and telephone conferences. Results A total of 15,246 samples have been HLA genotyped at eight loci to four-digit resolution; an additional 6797 samples have been HLA genotyped at two loci. The genotyping repeat rate decreased significantly over time, with an estimated unresolved Mendelian inconsistency rate of 0.21%. Annual quality control exercises tested 2192 genotypes (4384 alleles) and achieved 99.82% intra-laboratory and 99.68% inter-laboratory concordances. Limitations The chosen genotyping platform was unable to distinguish many allele combinations, which would require further multiple stepwise testing to resolve. For these combinations, a standard allele assignment was agreed upon, allowing further analysis if required. Conclusions High-resolution HLA genotyping can be performed in multiple laboratories using standard equipment, reagents, protocols, software, and communication to produce consistent and reproducible data with minimal systematic error. Many of the strategies used in this study are generally applicable to other large multi-center studies. Clinical Trials 2010; 7: S75-S87. http://ctj.sagepub.com.
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| 2. |
- Noble, Janelle A., et al.
(författare)
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HLA Class I and Genetic Susceptibility to Type 1 Diabetes Results From the Type 1 Diabetes Genetics Consortium
- 2010
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 59:11, s. 2972-2979
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE-We report here genotyping data and type 1 diabetes association analyses for HLA class I loci (A, B, and C) on 1,753 multiplex pedigrees from the Type 1 Diabetes Genetics Consortium (T1DGC), a large international collaborative study. RESEARCH DESIGN AND METHODS-Complete eight-locus HLA genotyping data were generated. Expected patient class I (HLA-A, -B, and -C) allele frequencies were calculated, based on linkage disequilibrium (LD) patterns with observed HLA class II DRB1-DQA1-DQB1 haplotype frequencies. Expected frequencies were compared to observed allele frequencies in patients. RESULTS-Significant type 1 diabetes associations were observed at all class I HLA loci. After accounting for LD with HLA class II, the most significantly type 1 diabetes-associated alleles were B*5701 (odds ratio 0.19; P = 4 x 10(-11)) and B*3906 (10.31; P = 4 X 10(-10)). Other significantly type 1 diabetes-associated alleles included A*2402, A*0201, B*1801, and C*0501 (predisposing) and A*1101, A*3201, A*6601, B*0702, B*4403, B*3502, C*1601, and C*0401 (protective). Some alleles, notably B*3906, appear to modulate the risk of all DRB1-DQA1-DQB1 haplotypes on which they reside, suggesting a class I effect that is independent of class H. Other class I type 1 diabetes associations appear to be specific to individual class H haplotypes. Some apparent associations (e.g., C*1601) could be attributed to strong LD to another class I susceptibility locus (B*4403). CONCLUSIONS-These data indicate that HLA class I alleles, in addition to and independently from HLA class H alleles, are associated with type 1 diabetes. Diabetes 59:2972-2979, 2010
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| 3. |
- Varney, Michael D., et al.
(författare)
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HLA DPA1, DPB1 Alleles and Haplotypes Contribute to the Risk Associated With Type 1 Diabetes Analysis of the Type 1 Diabetes Genetics Consortium Families
- 2010
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 59:8, s. 2055-2062
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE-To determine the relative risk associated with DPA1 and DPB1 alleles and haplotypes in type I diabetes. RESEARCH DESIGN AND METHODS-The frequency of DPA1 and DPB1 alleles and haplotypes in type I diabetic patients was compared to the family based control frequency in 1,771 families directly and conditional on FILA (B)-DRB1-DQA1-DQB1 linkage disequilibrium. A relative predispositional analysis (RPA) was performed in the presence or absence of the primary HLA DR-DQ associations and the contribution of DP haplotype to individual DR-DQ haplotype risks examined. RESULTS-Eight DPAI and thirty-eight DPB1 alleles forming seventy-four DPA1-DPB1 haplotypes were observed, nineteen DPB1 alleles were associated with multiple DPA1 alleles Following both analyses, type I diabetes susceptibility was significantly associated with DPB1*0301 (DPA1*0103-DPB1*0301) and protection with DPB1*0402 (DPA1*0103-DPB1*0402) and DPA1*0103-DPB1*0101 but not DPA1*0201-DPB1*0101. In addition, DPB1*0202 (DPA1*0103-DPB1*0202) and DPB1*0201 (DPA1*0103-DPB1*0201) were significantly associated with susceptibility in the presence of the high risk and protective DR-DQ haplotypes Three associations (DPB1*0301, *0402, and *0202) remained statistically significant when only the extended HLA-A1-B8-DR3 haplotype was considered, suggesting that DPB1 alone may delineate the risk associated with this otherwise conserved haplotype CONCLUSIONS-HLA DP allelic and haplotypic diversity contributes significantly to the risk for type I diabetes; DPB1*0301 (DPA1*0103-DPB1*0301) is associated with susceptibility and DPB1*0402 (DPA1*0103-DPB1*0402) and DPA1*0103-DPB1*0101 with protection Additional evidence is presented for the susceptibility association of DPB1*0202 (DPA1*0103-DPB1*0202) and for a contributory role of individual amino acids and DPA1 or a gene in linkage disequilibrium in DR3-DPB1*0101 positive haplotypes Diabetes 59:2055-2062, 2010
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