RESUMO
Type 1 diabetes mellitus (T1D) is an organ-specific autoimmune disease characterized by T-cell mediated self-destruction of insulin-producing ß cells in the pancreas. T1D patients are prone to develop other glandular autoimmune disorders, such as autoimmune thyroid disease that occurs simultaneously with autoimmune polyglandular syndrome type III (APSIII). Signal transducer and activator of transcription 4 (STAT4) is a well-known regulator of proinflammatory cytokines, and interferon-induced with helicase C domain 1 (IFIH1) is activated in the interferon type I response. Both genes have been examined separately in autoimmune diseases and, in this study, we assessed their joint role in T1D and APSIII. We conducted a case-control study, enrolling 173 T1D patients and 191 healthy controls from northeastern Brazil, to assess the distribution of the rs7574865 and rs3024839 SNPs in STAT4 and the rs3747517 and rs1990760 SNPs in IFIH1 in T1D and APSIII patients. Additionally, we conducted a meta-analysis with the rs7574865 SNP in STAT4 (1392 T1D patients and 1629 controls) and the rs1990760 SNP in IFIH1 (25092 T1D patients and 28544 controls) to examine their association with T1D. Distribution of STAT4 and IFIH1 allelic frequencies did not show statistically significant differences between T1D patients and controls in our study population; however, the meta-analysis indicated that SNPs in STAT4 and IFIH1 are associated with T1D worldwide. Our findings indicate that although STAT4 and IFIH1 SNPs are not associated with T1D in a Brazilian population, they might play a role in susceptibility to T1D on a larger worldwide scale.
Assuntos
RNA Helicases DEAD-box/genética , Diabetes Mellitus Tipo 1/genética , Poliendocrinopatias Autoimunes/genética , Fator de Transcrição STAT4/genética , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/patologia , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Lactente , Recém-Nascido , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/patologia , Helicase IFIH1 Induzida por Interferon , Masculino , Pessoa de Meia-Idade , Poliendocrinopatias Autoimunes/complicações , Poliendocrinopatias Autoimunes/patologia , Polimorfismo de Nucleotídeo Único , Transdução de Sinais/genéticaRESUMO
Type 1 diabetes mellitus (T1D) is a complex disorder characterized by an autoimmune response against human pancreatic beta-cells. Patients with T1D can also develop a response toward one or more other factors, such as in autoimmune thyroiditis (AITD) and celiac disease (CD). In the presence of T1D + AITD, the patient is diagnosed with autoimmune polyglandular syndrome type III (APSIII); patients with APSIII may also present with CD. These diseases have a strong genetic component and share many susceptibility genes, suggesting potentially overlapping pathogenic pathways. Polymorphisms in the TNF-α(rs1800629), CTLA-4 (rs231775), and PTPN22 (rs2476601) genes have been previous associated with T1D; however, there is no consensus regarding their role in T1D and scarce literature focusing on AIDT and/or CD. Thus, we analyzed these genetic variants in 205 Northeast Brazilian patients with T1D and with/without AITD and/or CD, and in 308 healthy controls. The PTPN22 gene variants were associated with T1D susceptibility and APSIII [odds ratio (OR) = 2.57 and 2.77, respectively]. CTLA4 rs231775 and TNF-αrs1800629 were not associated with T1D onset in the Brazilian population. However, when comparing APSIII individuals in the T1D only group, we observed an association of the TNF-αSNP in the allelic (P = 0.0442; OR = 0.44) and dominant models (P = 0.0387; OR = 0.40). This study reinforces the importance of CTLA-4 and other variants in unraveling the pathogenic mechanisms of T1D in different populations and in understanding their relationships with the development of other T1D-related autoimmune diseases.
Assuntos
Antígeno CTLA-4/genética , Diabetes Mellitus Tipo 1/genética , Proteína Tirosina Fosfatase não Receptora Tipo 22/genética , Fator de Necrose Tumoral alfa/genética , Adolescente , Adulto , Idade de Início , Brasil , Criança , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA , Adulto JovemRESUMO
We analyzed three functional 5' un-translated region beta-defensin 1 (DEFB1) single nucleotide polymorphism (SNPs) in a group of 170 type 1 diabetes (T1D) patients. In order to evaluate the SNPs influence on the disease onset and the development of other autoimmune disorder, such as celiac disease (CD) and autoimmune thyroid disease (AITD), patients were stratified according to the presence of AITD, CD, and both AITD and CD. As control group, we studied 191 healthy children and adolescent not presenting a familiar historic of T1D, CD or AITD. DEFB1 SNPs were in Hardy-Weinberg equilibrium both in healthy controls and T1D patients, as well in the T1D patients stratified according to the presence of other autoimmune disorder(s). Allele, genotype, and haplotype frequencies of T1D patients globally considered were comparable to healthy controls ones. No evidence of any association of DEFB1 SNPs with the onset of AIDT, CD, and both AITD and CD on T1D patients was evidenced. Only a minor trend was found for an increased frequency of the - 20 G allele in T1D patients only presenting AITD vs. T1D patients not presenting AITD or CD, as well as an increase of those haplotypes comprising the - 20 G allele when compared with the GCA haplotype. We also evaluated the influence of functional DEFB1 SNPs on the age of T1D onset: no significant statistical conclusion was achieved. Further studies are envisaged, in order to elucidate the possible role of functional DEFB1 polymorphisms in the onset of TD1 and other autoimmune-related disorders.