BACKGROUND: Several studies have demonstrated an association of type 1 diabetes with specific alleles of HLA class II molecules, as with polymorphisms of insulin gene region. The aim of our study was to evaluate the interaction of insulin -2221 MspI polymorphism to type 1 diabetes susceptibility in connection with autoimmunity associated gene--CTLA-4 polymorphism. MATERIALS AND METHODS: Insulin -2221 MspI C/T and CTLA-4 +49 A/G polymorphisms were detected by restriction fragment-length polymorphism analysis or oligonucleotide hybridization in type 1 (n = 69), type 2 diabetes (n = 301) patients and 158 healthy controls. Regression model adjusted for age, gender and gene polymorphisms was studied. RESULTS: C-allele of insulin -2221 MspI and G-allele of +49 CTLA-4 were significant risk factors for type 1 diabetes (crude OR 3.53 and 1.59, respectively) and this impact increased in the homozygous form of both alleles. The regression model supported the idea of insulin CC and CTLA-4 GG genotypes for an independent and clearly significant risk for developing type 1 diabetes. We could not detect any significant correlation between investigated polymorphisms and type 2 diabetes. CONCLUSIONS: There exists a significant association between the C-allele of -2221 MspI in the insulin gene and type 1 diabetes. The CTLA-4 G-allele is also positively correlated with type 1 diabetes. According to the regression model the investigated gene polymorphisms are independent risk factors for development of type 1 diabetes in the Estonian population. We propose that -2221 MspI is a good marker for evaluation of risk of insulin gene haplotype in type 1 diabetes patients. Copyright 2004 Blackwell Publishing Ltd
BACKGROUND: Several studies have demonstrated an association of type 1 diabetes with specific alleles of HLA class II molecules, as with polymorphisms of insulin gene region. The aim of our study was to evaluate the interaction of insulin -2221 MspI polymorphism to type 1 diabetes susceptibility in connection with autoimmunity associated gene--CTLA-4 polymorphism. MATERIALS AND METHODS:Insulin -2221 MspI C/T and CTLA-4+49 A/G polymorphisms were detected by restriction fragment-length polymorphism analysis or oligonucleotide hybridization in type 1 (n = 69), type 2 diabetes (n = 301) patients and 158 healthy controls. Regression model adjusted for age, gender and gene polymorphisms was studied. RESULTS: C-allele of insulin -2221 MspI and G-allele of +49 CTLA-4 were significant risk factors for type 1 diabetes (crude OR 3.53 and 1.59, respectively) and this impact increased in the homozygous form of both alleles. The regression model supported the idea of insulin CC and CTLA-4 GG genotypes for an independent and clearly significant risk for developing type 1 diabetes. We could not detect any significant correlation between investigated polymorphisms and type 2 diabetes. CONCLUSIONS: There exists a significant association between the C-allele of -2221 MspI in the insulin gene and type 1 diabetes. The CTLA-4 G-allele is also positively correlated with type 1 diabetes. According to the regression model the investigated gene polymorphisms are independent risk factors for development of type 1 diabetes in the Estonian population. We propose that -2221 MspI is a good marker for evaluation of risk of insulin gene haplotype in type 1 diabetespatients. Copyright 2004 Blackwell Publishing Ltd
Authors: Robert Hermann; A P Laine; R Veijola; T Vahlberg; S Simell; J Lähde; O Simell; M Knip; J Ilonen Journal: Diabetologia Date: 2005-07-16 Impact factor: 10.122
Authors: R Hermann; K Lipponen; M Kiviniemi; T Kakko; R Veijola; O Simell; M Knip; J Ilonen Journal: Diabetologia Date: 2006-04-14 Impact factor: 10.122