Tumour necrosis factor-beta polymorphism is unlikely to determine susceptibility to type 1 (insulin-dependent) diabetes mellitus.
Tumour necrosis factor gene polymorphism has been proposed as a determinant of Type 1 (insulin-dependent) diabetes mellitus. Tumour necrosis factor-beta gene polymorphisms were analysed in 40 North Indian Asian Type 1 diabetic patients and 63 control subjects. A 5.5 kilobase gene fragment was significantly increased among the patients (82.5% vs 52%, pc less than 0.01). A 10.5 kilobase fragment was significantly reduced among the patients (70% vs 90.5%, pc less than 0.02). The 5.5 kilobase fragment was associated with DR3, and was not significantly increased among DR3-positive patients compared with DR3-positive control subjects. The 5.5 kilobase/5.5 kilobase genotype was increased among the diabetic subjects (30% vs 9.5%, pc less than 0.03). The 10.5 kilobase/10.5 kilobase genotype was reduced among the diabetic subjects (17.5% vs 47.5%, pc less than 0.02). The 5.5 kilobase/10.5 kilobase genotype was not significantly associated with disease. These findings contrast with those in a white Caucasian population, suggesting that tumour necrosis factor-beta polymorphisms do not predispose to Type 1 diabetes directly, but are in linkage disequilibrium with disease susceptibility alleles at other MHC loci.
Department of Medicine, University of Birmingham, UK.
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Jenkins
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Penny
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Mijovic
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Jacobs
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Fletcher
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Barnett
D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology; D020022:Genetic Predisposition to Disease; D005838:Genotype; D015803:HLA-DR3 Antigen / Q000235:genetics; D006801:Humans; D007194:India / Q000208:ethnology; D008233:Lymphotoxin-alpha / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D012016:Reference Values; D006113:United Kingdom; D044465:White People
D015803:HLA-DR3 Antigen; D008233:Lymphotoxin-alpha