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OBJECTIVE - In contrast with childhood-onset type 1 diabetes, the genetics of autoimmune diabetes in adults are not well understood. We have therefore investigated the genetics of diabetes diagnosed in adults positive for autoantibodies. RESEARCH DESIGN AND METHODS - GAD autoantibodies (GADAs), insulinoma-associated antigen-2 antibodies (IA-2As), and islet cell autoantibodies were measured at time of diagnosis. Autoantibody-positive diabetic subjects (n = 1,384) and population- based control subjects (n = 2,235) were genotyped at 20 childhood-onset type 1 diabetes loci and FCRL3, GAD2, TCF7L2, and FTO. RESULTS - PTPN22 (1p13.2), STAT4 (2q32.2), CTLA4 (2q33.2), HLA (6p21), IL2RA (10p15.1), INS (11p15.5), ERBB3 (12q13.2), SH2B3 (12q24.12), and CLEC16A (16p13.13) were convincingly associated with autoimmune diabetes in adults (P ≤ 0.002), with consistent directions of effect as reported for pediatric type 1 diabetes. No evidence of an HLA-DRB1*03/HLA-DRB1*04 (DR3/4) genotype effect was obtained (P = 0.55), but it remained highly predisposing (odds ratio 26.22). DR3/4 was associated with a lower age at diagnosis of disease, as was DR4 (P = 4.67 × 10 -6) but not DR3. DR3 was associated with GADA positivity (P = 6.03 × 10 -6) but absence of IA-2A (P = 3.22 × 10 -7). DR4 was associated with IA-2A positivity (P = 5.45 × 10 -6). CONCLUSIONS - Our results are consistent with the hypothesis that the genetics of autoimmune diabetes in adults and children are differentiated by only relatively few age-dependent genetic effects. The slower progression toward autoimmune insulin deficiency in adults is probably due to a lower genetic load overall combined with subtle variation in the HLA class II gene associations and autoreactivity. © 2011 by the American Diabetes Association.

Original publication

DOI

10.2337/db11-0364

Type

Journal article

Journal

Diabetes

Publication Date

01/10/2011

Volume

60

Pages

2645 - 2653