Walter M, Albert E, Conrad M, Keller E, Hummel M, Ferber K, Barratt BJ, Todd JA, Ziegler AG, Bonifacio E. IDDM2/insulin VNTR modifies risk conferred by IDDM1/HLA for development of Type 1 diabetes and associated autoimmunity.
Diabetologia 2003;
46:712-20. [PMID:
12750767 DOI:
10.1007/s00125-003-1082-z]
[Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2002] [Revised: 12/17/2002] [Indexed: 01/16/2023]
Abstract
AIM/HYPOTHESIS
Type 1 diabetes (T1D) is an autoimmune disease with multiple susceptibility genes. The aim of this study was to determine whether combining IDDM1/HLA and IDDM2/ insulin( INS) 5' variable number of tandem repeat locus (VNTR) genotypes improves T1D risk assessment.
METHODS
Patients with T1D (n=488), control subjects (n=846), and offspring of parents with T1D (n=1122) were IDDM1 and IDDM2 genotyped. Offspring were followed for islet autoantibodies and T1D from birth until the age of 2 to 12 years.
RESULTS
Compared to the I/I INS VNTR genotype, the I/III and III/III genotypes reduced T1D risk conferred by IDDM1/HLA in all HLA genotype categories of the case-control cohort by 1.6-fold to three-fold. The highest T1D risk was associated with INS VNTR class I/I plus HLA DR3/DR4-DQ8 (20.4% in patients, 0.6% in control subjects) or HLA DR4-DQ8/DR4-DQ8 (6.3% in patients, 0.2% in control subjects). In the offspring, HLA DR3/DR4-DQ8 and DR4-DQ8/DR4-DQ8 conferred increased risk for early development of islet autoantibodies (14.6% and 12.9% by age 2 years). Offspring with these high risk IDDM1 genotypes plus the INS VNTR class I/I genotype (n=71; 6.3%) had the highest risk of developing islet autoantibodies (21.8% by age 2 years vs 8.9% in offspring with high risk IDDM1 plus INS VNTR class I/III or III/III genotypes, p<0.05) and T1D (8.5% by age 6 years vs 4.3%). Offspring who developed autoantibodies to multiple antigens had increased frequencies of both high risk IDDM1 and IDDM2 genotypes (p<0.0001), whereas offspring who developed autoantibodies to GAD only had increased frequencies of high risk IDDM1 and protective IDDM2 genotypes, suggesting that IDDM2 influences the autoimmune target specificity.
CONCLUSION/INTERPRETATION
Combining IDDM1 and IDDM2 genotyping identifies a minority of children with an increased T1D risk.
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