[Nozological Heterogeneity, Molecular Genetics and Immunology of Autoimmune Diabetes Mellitus].

Article is devoted to the review of literature data, and also the analysis of results of own researches concerning genetics, molecular genetics and immunological violations at various forms of the autoimmune diabetes (DM) including classical T1DM, LADA type and an autoimmune polyglandular syndrome of 1 type (APS1). In case of T1DM more than 80% of patients are carriers of one or two strongest predisposing haplotypes: DRB1*04-DQA1*0301-DQB1*0302 and DRB1*03-DQA1*0501-DQB1*0201 designated as DQ2 and DQ8. HLA genes can model a clinical features of disease. In Russian population, the children with diabetes manifestation up to 5-year age has significantly often high risk genotypes (DQ2/ DQ8) and significantly less the low risk genotypes in comparison with children, who had manifestation of T1DMin 10 years and later. The long-term 16-yearsfamily studies showed the maximum frequency of TJDMin high risk group, constantly accruing in process of increase in term of supervision, and in groups of an average and low risk lower and invariable. The highest risk of T1DM manifestation, reaching 90% at 10 years of supervision is defined by existence of HLA high risk genotypes and many antibodies, revealedfrom early age. LADA - the hybridform of autoimmune DM having signs of T1DM and T2DM in the basis. The development of autoimmune process against ß-cells can be caused by only gene mutation (APS1). The part of T1DM cases which doesn't have the contributing HLA genes and autoimmune markers in process of studying of the importance of various genes and their biological value can be attributed to new, yet unknown forms of DM.

[Prevention of diabetes mellitus: past, present, and future].

The incidence of type 1 diabetes mellitus (T1DM) is increasing in many countries of the world, the average annual increase in the frequency of the disease in European children is 3.4% at the age of 0-14 and 6.3% at the age of 0-5. The increase in the incidence of type 1 diabetes at an early age has a definite effect on the whole society as a whole, increasing the burden both on the patients themselves and their families, in particular, leading to an earlier development of complications. Since these changes in the development of diabetes have occurred too quickly to be due to changes at the genetic level, they are most likely a consequence of environmental changes.

Evidence for a type 1 diabetes susceptibility locus (IDDM10) on chromosome 10p11-q11 in a Russian population.

Around 20 susceptibility loci for type 1 diabetes mellitus (T1DM) have been mapped. One of these loci, IDDM10, was found on chromosome 10p11-q11. Here, we investigated whether the IDDM10 locus contributes in the susceptibility to T1DM in a Russian family dataset. One hundred and fourteen simplex Russian families, each containing two siblings (one affected with T1DM diagnosed and one nondiabetic sibling), and 97 multiplex families, containing 106 affected full sibling pairs, were studied. Genomic DNA from the venous blood of the patients was genotyped by PCR using 12 microsatellites (D10S193, D10S548, D10S565, D10S586, D10S588, D10S675, D10S1243, D10S1426, D10S1733, D10S1772, D10S1780 and D10S1783) located on chromosome 10p11-q11. Using the multipoint linkage analysis, the region of suggestive linkage, with a multipoint logarithm of odds (LOD) ratio (MLS) value of more than 2.2, was found between markers D10S1733 and D10S1780, an area of 9.0 cM on the genetic map. The maximum linkage peak (MLS = 2.85 and nonparametric logarithm = 2.68) was observed between markers D11S565 and D11S1243. Using the transmission disequilibrium test, an association of these markers, D10S565 (P overall = 0.0082) and D10S1243 (P overall = 0.017), with T1DM was shown. These results suggest the evidence for the IDDM10 susceptibility locus on chromosome 10p11-q11.

A new type 1 diabetes susceptibility locus containing the catalase gene (chromosome 11p13) in a Russian population.

BACKGROUND: Oxidative stress is involved in the origin of type 1 diabetes. Low efficiency of the scavenging antioxidant system has been shown to be related to the pathogenesis of the disease. This, therefore suggests that genes encoding catalase and other antioxidant enzymes may implicate in the development of type 1 diabetes. METHODS: Nine microsatellite markers that cover about 10 megabases around the catalase (CAT) gene on chromosome 11p13 were analyzed using polymerase chain reaction (PCR) and fluorescence-based genotyping on an automatic DNA sequencer. We also evaluated three single-nucleotide polymorphisms (SNP) within genes encoding catalase (T1667T and C(-262)T dimorphism) and ETS homologous factor (EHF) (C255T SNP) using a PCR-restriction fragment-length polymorphism approach. Multipont linkage analysis in 37 affected sibling pairs was performed using GENEHUNTER 2.1. We examined the markers for association with the disease by transmission disequilibrium tests in 57 discordant sibling pairs and by a case-control study in 258 unrelated healthy donors and 247 affected patients. RESULTS: We obtained close-to-suggestive evidence of linkage to type I diabetes, with the maximum linkage peak between markers D11S907 and D11S2008. Analysis of three SNPs at the CAT and EHF gene located within the region of maximum linkage showed that T1667T and C(-262)T markers of the CAT gene are strongly associated with the disease. CONCLUSION: Our findings support evidence of a new putative type 1 diabetes susceptibility locus on chromosome 11p13 and suggest that the CAT gene may play a role in conferring susceptibility to the disorder in Russian patients.

[Genetic and immunologic aspects of type 1 diabetes mellitus]. / Geneticheskie i immunologicheskie aspekty sakharnogo diabeta 1-go tipa.

Prediction of type 1 diabetes mellitus (IDDM) and its identification in preclinical period is one of the central problems in modern medicine. They are based comprehensive genetic, immunologic and metabolic evaluations. We observed four hundred seven first-degree relatives of patients with IDDM (240 families in which one of the children or one of the parents had IDDM) have been included in the study. The study of HLA-DQA1, HLA-DQB1 polymorphic alleles and DRB1 genes and their combinations. The genetic study included searching HLA loci (HLA-DQA1, HLA-DQB1 polymorphic alleles and DRB1 genes) loci. To evaluate the genetic risk two approaches we used: first--carrying predisposing HLA-DQ alleles and DRB1-genes and it's combination (mainly associated in Russian population was DRB1*04-DQB1*0302, DRB1*04-DQA1*0301, DQA1*0301-DQB1*0302, DQA1*0301-DQB1*0302 and four susceptible alleles in A- and B- chains (Asp 57-, Arg 52+)) and second--IBD (identity by descent), in Russian population HLA-identical for 2 haplotypes sibs had risk of development of IDDM of 18%, for 1 haplotype--3%, for 0 haplotype-0.9%. The antibodies (ICA, IAA) prevalence rate has not depended on availability of predisposing HLA-DQ alleles and DRB1-genes and haploidentity of normal sibs and sibs with IDDM. However, GADA prevalence rate in groups having high predisposed alleles has been noticed as significantly higher (28.6%) comparing with 7.7% in groups that had no predisposing alleles (p < 0.05). The comparison of antibodies prevalence rate to sibs HLA-identity has shown the significant increase or GADA prevalence rate in group of siblings identical for one haplotype comparing with non-identical sibs (27.3% and 0% respectively, p < 0.001).