| 1. |
- Graham, Jinko, et al.
(author)
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Negative association between type 1 diabetes and HLA DQB1*0602-DQA1*0102 is attenuated with age at onset
- 1999
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In: European Journal of Immunogenetics. - : Wiley. - 0960-7420 .- 1365-2370. ; 26, s. 117-
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Journal article (peer-reviewed)abstract
- HLA-associated relative risks of type 1 (insulin-dependent) diabetes mellitus were analysed in population-based Swedish patients and controls aged 0-34 years. The age dependence of HLA-associated relative risks was assessed by likelihood ratio tests of regression parameters in separate logistic regression models for each HLA category. The analyses demonstrated an attenuation with increasing age at onset in the relative risk for the positively associated DQB1*0201-A1*0502/B1*0302-A1*0301 (DQ2/8) genotype (P = 0.02) and the negatively associated DQB1*0602-A1*0102 (DQ6.2) haplotype (P = 0.004). At birth, DQ6.2-positive individuals had an estimated relative risk of 0.03, but this increased to 1.1 at age 35 years. Relative risks for individuals with DQ genotype 8/8 or 8/X or DQ genotype 2/2 or 2/X, where X is any DQ haplotype ether than 2, 8 or 6.2, were not significantly age-dependent. An exploratory analysis of DQ haplotypes other than 2, 8 and 6.2 suggested that the risk of type 1 diabetes increases with age for DQB1*0604-A1*0102 (DQ6.4) and that the peak risk for the negatively associated DQB1*0301-A1*0501 haplotype is at age 18 years. There was also weak evidence that the risk for DQB1*0303-A1*0301 (DQ9), which has a positive association in the Japanese population, may decrease with age. We speculate that HLA-DQ alleles have a significant effect on the rate of beta cell destruction, which is accelerated in DQ2/8-positive individuals and inhibited, but not completely blocked, in DQ6.2-positive individuals.
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| 2. |
- Hagopian, William A., et al.
(author)
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Glutamate decarboxylase-, insulin-, and islet cell-antibodies and HLA typing to detect diabetes in a general population-based study of Swedish children
- 1995
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In: Journal of Clinical Investigation. - 0021-9738. ; 95:4, s. 1505-1511
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Journal article (peer-reviewed)abstract
- Most autoimmune diabetes occurs in those without a diabetic relative, but few cases are identifiable prospectively. To model general population prediction, 491 consecutive newly diabetic children from all of Sweden were tested for autoantibodies to glutamate decarboxylase (GAD65ab), insulin (IAA), and islet cells (ICA), and for HLA-DQ genotypes by PCR; 415 matched control children were tested in parallel. GAD65ab sensitivity/specificity was 70/96%, versus 84/96% for ICA, 56/97% for IAA, 93/93% (any positive), 39/99.7% (all positive), and 41/99.7% (GAD65ab plus IAA). The latter's 25% predictive value was not improved by requiring concomitant high-risk HLA genotypes. GAD65ab were associated with DQA1*0501/B1*0201 (DQ2; P = 0.007) but not DQA1*0301/B1*0302 (DQ8), and IAA with DQA1*0301/B1*0302 (DQ8; P = 0.03) but not DQA1*0501/B1*0201 (DQ2). GAD65ab were more prevalent in females than males (79 vs. 63%; P < 0.0001) but did not vary with onset age nor season. Combining the three antibody assays yielded sufficient sensitivity for screening. GADab were relatively sensitive/specific for diabetes, but even with HLA marker combinations yielded predictive values insufficient for early immunointervention in the low-prevalence general population.
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