RESUMO
Hundreds of genomic loci have been associated with a significant number of immune-mediated diseases, and a large proportion of these associated loci are shared among traits. Both the molecular mechanisms by which these loci confer disease susceptibility and the extent to which shared loci are implicated in a common pathogenesis are unknown. We therefore sought to dissect the functional components at loci shared between two autoimmune diseases: coeliac disease (CeD) and rheumatoid arthritis (RA). We used a cohort of 12 381 CeD cases and 7827 controls, and another cohort of 13 819 RA cases and 12 897 controls, all genotyped with the Immunochip platform. In the joint analysis, we replicated 19 previously identified loci shared by CeD and RA and discovered five new non-HLA loci shared by CeD and RA. Our fine-mapping results indicate that in nine of 24 shared loci the associated variants are distinct in the two diseases. Using cell-type-specific histone markers, we observed that loci which pointed to the same variants in both diseases were enriched for marks of promoters active in CD14+ and CD34+ immune cells (P < 0.001), while loci pointing to distinct variants in one of the two diseases showed enrichment for marks of more specialized cell types, like CD4+ regulatory T cells in CeD (P < 0.0001) compared with Th17 and CD15+ in RA (P = 0.0029).
Assuntos
Artrite Reumatoide/genética , Doença Celíaca/genética , Artrite Reumatoide/imunologia , Linfócitos T CD4-Positivos , Doença Celíaca/imunologia , Mapeamento Cromossômico , Estudos de Coortes , Estudos de Associação Genética , Humanos , Locos de Características QuantitativasRESUMO
Although genome-wide association studies and fine mapping have identified 39 non-HLA loci associated with celiac disease (CD), it is difficult to pinpoint the functional variants and susceptibility genes in these loci. We applied integrative approaches to annotate and prioritize functional single nucleotide polymorphisms (SNPs), genes and pathways affected in CD. CD-associated SNPs were intersected with regulatory elements categorized by the ENCODE project to prioritize functional variants, while results from cis-expression quantitative trait loci (eQTL) mapping in 1469 blood samples were combined with co-expression analyses to prioritize causative genes. To identify the key cell types involved in CD, we performed pathway analysis on RNA-sequencing data from different immune cell populations and on publicly available expression data on non-immune tissues. We discovered that CD SNPs are significantly enriched in B-cell-specific enhancer regions, suggesting that, besides T-cell processes, B-cell responses play a major role in CD. By combining eQTL and co-expression analyses, we prioritized 43 susceptibility genes in 36 loci. Pathway and tissue-specific expression analyses on these genes suggested enrichment of CD genes in the Th1, Th2 and Th17 pathways, but also predicted a role for four genes in the intestinal barrier function. We also discovered an intricate transcriptional connectivity between CD susceptibility genes and interferon-γ, a key effector in CD, despite the absence of CD-associated SNPs in the IFNG locus. Using systems biology, we prioritized the CD-associated functional SNPs and genes. By highlighting a role for B cells in CD, which classically has been described as a T-cell-driven disease, we offer new insights into the mechanisms and pathways underlying CD.
Assuntos
Doença Celíaca/genética , Interferon gama/metabolismo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Doença Celíaca/metabolismo , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Interferon gama/genética , Anotação de Sequência MolecularRESUMO
Using the Immunochip for genotyping, we identified 39 non-human leukocyte antigen (non-HLA) loci associated to celiac disease (CeD), an immune-mediated disease with a worldwide frequency of â¼1%. The most significant non-HLA signal mapped to the intronic region of 70 kb in the LPP gene. Our aim was to fine map and identify possible functional variants in the LPP locus. We performed a meta-analysis in a cohort of 25 169 individuals from six different populations previously genotyped using Immunochip. Imputation using data from the Genome of the Netherlands and 1000 Genomes projects, followed by meta-analysis, confirmed the strong association signal on the LPP locus (rs2030519, P = 1.79 × 10(-49)), without any novel associations. The conditional analysis on this top SNP-indicated association to a single common haplotype. By performing haplotype analyses in each population separately, as well as in a combined group of the four populations that reach the significant threshold after correction (P < 0.008), we narrowed down the CeD-associated region from 70 to 2.8 kb (P = 1.35 × 10(-44)). By intersecting regulatory data from the ENCODE project, we found a functional SNP, rs4686484 (P = 3.12 × 10(-49)), that maps to several B-cell enhancer elements and a highly conserved region. This SNP was also predicted to change the binding motif of the transcription factors IRF4, IRF11, Nkx2.7 and Nkx2.9, suggesting its role in transcriptional regulation. We later found significantly low levels of LPP mRNA in CeD biopsies compared with controls, thus our results suggest that rs4686484 is the functional variant in this locus, while LPP expression is decreased in CeD.
Assuntos
Doença Celíaca/genética , Proteínas do Citoesqueleto/genética , Proteínas com Domínio LIM/genética , Polimorfismo de Nucleotídeo Único/genética , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla , Haplótipos , Humanos , Fatores Reguladores de Interferon/genética , Desequilíbrio de Ligação , Fatores de Transcrição/genéticaRESUMO
Genome-wide association and fine-mapping studies in 14 autoimmune diseases (AID) have implicated more than 250 loci in one or more of these diseases. As more than 90% of AID-associated SNPs are intergenic or intronic, pinpointing the causal genes is challenging. We performed a systematic analysis to link 460 SNPs that are associated with 14 AID to causal genes using transcriptomic data from 629 blood samples. We were able to link 71 (39%) of the AID-SNPs to two or more nearby genes, providing evidence that for part of the AID loci multiple causal genes exist. While 54 of the AID loci are shared by one or more AID, 17% of them do not share candidate causal genes. In addition to finding novel genes such as ULK3, we also implicate novel disease mechanisms and pathways like autophagy in celiac disease pathogenesis. Furthermore, 42 of the AID SNPs specifically affected the expression of 53 non-coding RNA genes. To further understand how the non-coding genome contributes to AID, the SNPs were linked to functional regulatory elements, which suggest a model where AID genes are regulated by network of chromatin looping/non-coding RNAs interactions. The looping model also explains how a causal candidate gene is not necessarily the gene closest to the AID SNP, which was the case in nearly 50% of cases.
Assuntos
Doenças Autoimunes/genética , Mapeamento Cromossômico , Expressão Gênica , Variação Genética , Estudo de Associação Genômica Ampla , Locos de Características Quantitativas , RNA não Traduzido , Doenças Autoimunes/metabolismo , Autofagia/genética , Doença Celíaca/genética , Doença Celíaca/metabolismo , Citocinas/metabolismo , Regulação da Expressão Gênica , Predisposição Genética para Doença , Genoma Humano , Genômica , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Desequilíbrio de Ligação , Polimorfismo de Nucleotídeo Único , RNA Longo não Codificante/genéticaRESUMO
OBJECTIVE: Certain HLA-DRB1 alleles and single-nucleotide polymorphisms (SNPs) are associated with rheumatoid arthritis (RA). Our objective was to examine the combined effect of these associated variants, calculated as a cumulative genetic risk score (GRS) on RA predisposition, as well as the number of autoantibodies (none, one or two present). METHOD: We calculated four GRSs in 4956 patients and 4983 controls from four European countries. All four scores contained data on 22 non-HLA-risk SNPs, and three scores also contained HLA-DRB1 genotypes but had different HLA typing resolution. Most patients had data on both rheumatoid factor (RF) and anti-citrullinated proteins antibodies (ACPA). The GRSs were standardised (std.GRS) to account for population heterogeneity. Discrimination between patients and controls was examined by receiveroperating characteristics curves, and the four std.GRSs were compared across subgroups according to autoantibody status. RESULTS: The std.GRS improved its discriminatory ability between patients and controls when HLA-DRB1 data of higher resolution were added to the combined score. Patients had higher mean std.GRS than controls (p=7.9×10(-156)), and this score was significantly higher in patients with autoantibodies (shown for both RF and ACPA). Mean std.GRS was also higher in those with two versus one autoantibody (p=3.7×10(-23)) but was similar in patients without autoantibodies and controls (p=0.12). CONCLUSIONS: The GRS was associated with the number of autoantibodies and to both RF and ACPA positivity. ACPA play a more important role than RF with regards to the genetic risk profile, but stratification of patients according to both RF and ACPA may optimise future genetic studies.
Assuntos
Artrite Reumatoide/genética , Autoanticorpos/imunologia , Cadeias HLA-DRB1/genética , Alelos , Artrite Reumatoide/imunologia , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Peptídeos Cíclicos/imunologia , Fator Reumatoide/imunologia , Medição de Risco , Fatores de Risco , População BrancaRESUMO
BACKGROUND: The majority of coeliac disease (CD) patients are not being properly diagnosed and therefore remain untreated, leading to a greater risk of developing CD-associated complications. The major genetic risk heterodimer, HLA-DQ2 and DQ8, is already used clinically to help exclude disease. However, approximately 40% of the population carry these alleles and the majority never develop CD. OBJECTIVE: We explored whether CD risk prediction can be improved by adding non-HLA-susceptible variants to common HLA testing. DESIGN: We developed an average weighted genetic risk score with 10, 26 and 57 single nucleotide polymorphisms (SNP) in 2675 cases and 2815 controls and assessed the improvement in risk prediction provided by the non-HLA SNP. Moreover, we assessed the transferability of the genetic risk model with 26 non-HLA variants to a nested case-control population (n=1709) and a prospective cohort (n=1245) and then tested how well this model predicted CD outcome for 985 independent individuals. RESULTS: Adding 57 non-HLA variants to HLA testing showed a statistically significant improvement compared to scores from models based on HLA only, HLA plus 10 SNP and HLA plus 26 SNP. With 57 non-HLA variants, the area under the receiver operator characteristic curve reached 0.854 compared to 0.823 for HLA only, and 11.1% of individuals were reclassified to a more accurate risk group. We show that the risk model with HLA plus 26 SNP is useful in independent populations. CONCLUSIONS: Predicting risk with 57 additional non-HLA variants improved the identification of potential CD patients. This demonstrates a possible role for combined HLA and non-HLA genetic testing in diagnostic work for CD.
Assuntos
Doença Celíaca/diagnóstico , Técnicas de Apoio para a Decisão , Predisposição Genética para Doença , Testes Genéticos , Antígenos HLA-DQ/genética , Polimorfismo de Nucleotídeo Único , Estudos de Casos e Controles , Doença Celíaca/genética , Feminino , Marcadores Genéticos , Humanos , Modelos Logísticos , Masculino , Modelos Genéticos , Modelos de Riscos Proporcionais , Estudos Prospectivos , Curva ROC , Medição de RiscoRESUMO
In the past few years there has been enormous progress in unraveling the genetic basis of celiac disease (CD). Apart from the well-known association to HLA, there are currently 40 genomic loci associated to CD. Most of these loci show pleiotropic effects across many autoimmune diseases and highlight the importance of a dysregulated immune system in the predisposition to CD. It is still too early, however, to use genetics in clinical practice for predicting individual risk. The major challenge for the future is to translate genetic findings into a better understanding of the underlying disease mechanism and to design new ways to treat CD and prevent its development.
Assuntos
Doença Celíaca/genética , Loci Gênicos , Predisposição Genética para Doença , Doenças Autoimunes/genética , Doença Celíaca/imunologia , Pleiotropia Genética , Antígenos HLA/genética , Humanos , Fatores de RiscoRESUMO
Celiac disease (CeD) is a common immune-mediated disease of the small intestine that is triggered by exposure to dietary gluten. While the HLA locus plays a major role in disease susceptibility, 39 non-HLA loci were also identified in a study of 24,269 individuals. We now build on this earlier study by adding 4125 additional Caucasian samples including an Argentinian cohort. In doing so, we not only confirm the previous associations, we also identify two novel independent genome-wide significant associations at loci: 12p13.31 and 22q13.1. By applying a genomics approach and differential expression analysis in CeD intestinal biopsies, we prioritize potential causal genes at these novel loci, including LTBR, CYTH4, and RAC2. Nineteen prioritized causal genes are overlapping known drug targets. Pathway enrichment analysis and expression of these genes in CeD biopsies suggest that they have roles in regulating multiple pathways such as the tumor necrosis factor (TNF) mediated signaling pathway and positive regulation of I-κB kinase/NF-κB signaling.
Assuntos
Doença Celíaca/genética , Loci Gênicos , Polimorfismo de Nucleotídeo Único , Argentina , Doença Celíaca/patologia , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Cromossomos Humanos Par 12/genética , Cromossomos Humanos Par 22/genética , Europa (Continente) , Estudo de Associação Genômica Ampla , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Receptor beta de Linfotoxina/genética , Receptor beta de Linfotoxina/metabolismo , NADPH Oxidases/genética , NADPH Oxidases/metabolismo , NF-kappa B/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas rac de Ligação ao GTP/genética , Proteínas rac de Ligação ao GTP/metabolismo , Proteína RAC2 de Ligação ao GTPRESUMO
The MHC/HLA region has been consistently associated with a large number of complex traits, including but not limited to, most immune-mediated ones. Efforts to pinpoint drivers of this commonly encountered association peak at the short arm of chromosome 6, however, have been challenging, owing to the high density of genes and the long and extended linkage disequilibrium that are characteristic of this region.The development of methods to impute classical HLA alleles and amino acids from SNP genotyping data has offered an important additional layer of information to the investigators seeking to fine map the signal in the region. As a result, imputation-aided association analyses are now typically employed to shed light on the relationship of this locus with disease susceptibility and response to drugs.In this chapter we discuss how the signal in the HLA region can be interrogated in practice, from performing the imputation to understanding its output and to incorporating it into downstream analysis. In addition, we recount some of the analytical approaches that are commonly used and suggest ways in which the findings from such imputation-aided analyses can be interpreted.
Assuntos
Estudos de Associação Genética , Predisposição Genética para Doença , Antígenos HLA/genética , Alelos , Biologia Computacional/métodos , Suscetibilidade a Doenças , Estudos de Associação Genética/métodos , Variação Genética , Estudo de Associação Genômica Ampla , Genótipo , Antígenos HLA/imunologia , HumanosRESUMO
BACKGROUND: In recent years, research has consistently proven the occurrence of genetic overlap across autoimmune diseases, which supports the existence of common pathogenic mechanisms in autoimmunity. The objective of this study was to further investigate this shared genetic component. METHODS: For this purpose, we performed a cross-disease meta-analysis of Immunochip data from 37,159 patients diagnosed with a seropositive autoimmune disease (11,489 celiac disease (CeD), 15,523 rheumatoid arthritis (RA), 3477 systemic sclerosis (SSc), and 6670 type 1 diabetes (T1D)) and 22,308 healthy controls of European origin using the R package ASSET. RESULTS: We identified 38 risk variants shared by at least two of the conditions analyzed, five of which represent new pleiotropic loci in autoimmunity. We also identified six novel genome-wide associations for the diseases studied. Cell-specific functional annotations and biological pathway enrichment analyses suggested that pleiotropic variants may act by deregulating gene expression in different subsets of T cells, especially Th17 and regulatory T cells. Finally, drug repositioning analysis evidenced several drugs that could represent promising candidates for CeD, RA, SSc, and T1D treatment. CONCLUSIONS: In this study, we have been able to advance in the knowledge of the genetic overlap existing in autoimmunity, thus shedding light on common molecular mechanisms of disease and suggesting novel drug targets that could be explored for the treatment of the autoimmune diseases studied.
Assuntos
Doenças Autoimunes/genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Artrite Reumatoide/genética , Doença Celíaca/genética , Diabetes Mellitus Tipo 1/genética , Estudo de Associação Genômica Ampla , Humanos , Anotação de Sequência Molecular , Escleroderma Sistêmico/genéticaRESUMO
BACKGROUND: Approximately 5% of patients with celiac disease (CeD) do not respond to a gluten-free diet and progress to refractory celiac disease (RCD), a severe progression that is characterized by infiltration of intraepithelial T lymphocytes. Patients with RCD type II (RCDII) show clonal expansions of intraepithelial T lymphocytes that result in a poor prognosis and a high mortality rate through development of aggressive enteropathy-associated T-cell lymphoma. It is not known whether genetic variations play a role in severe progression of CeD to RCDII. PATIENTS AND METHODS: We performed the first genome-wide association study to identify the causal genes for RCDII and the molecular pathways perturbed in RCDII. The genome-wide association study was performed in 38 Dutch patients with RCDII, and the 15 independent top-associated single nucleotide polymorphism (SNP) variants (P<5×10) were replicated in 56 independent French and Dutch patients with RCDII. RESULTS: After replication, SNP rs2041570 on chromosome 7 was significantly associated with progression to RCDII (P=2.37×10, odds ratio=2.36) but not with CeD susceptibility. SNP rs2041570 risk allele A was associated with lower levels of FAM188B expression in blood and small intestinal biopsies. Stratification of RCDII biopsies based on rs2041570 genotype showed differential expression of innate immune and antibacterial genes that are expressed in Paneth cells. CONCLUSION: We have identified a novel SNP associated with the severe progression of CeD to RCDII. Our data suggest that genetic susceptibility to CeD might be distinct from the progression to RCDII and suggest a role for Paneth cells in RCDII progression.
Assuntos
Doença Celíaca/genética , Cromossomos Humanos Par 7/genética , Polimorfismo de Nucleotídeo Único , Biópsia , Estudos de Casos e Controles , Doença Celíaca/diagnóstico , Doença Celíaca/dietoterapia , Doença Celíaca/imunologia , Dieta Livre de Glúten , Progressão da Doença , Feminino , França , Microbioma Gastrointestinal/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Humanos , Imunidade Inata/genética , Intestino Delgado/imunologia , Intestino Delgado/microbiologia , Intestino Delgado/patologia , Masculino , Proteínas de Membrana/genética , Análise Multivariada , Países Baixos , Razão de Chances , Celulas de Paneth/imunologia , Celulas de Paneth/microbiologia , Celulas de Paneth/patologia , Fenótipo , Fatores de Risco , Índice de Gravidade de Doença , Falha de TratamentoRESUMO
Genetic association studies have identified 215 risk loci for inflammatory bowel disease, thereby uncovering fundamental aspects of its molecular biology. We performed a genome-wide association study of 25,305 individuals and conducted a meta-analysis with published summary statistics, yielding a total sample size of 59,957 subjects. We identified 25 new susceptibility loci, 3 of which contain integrin genes that encode proteins in pathways that have been identified as important therapeutic targets in inflammatory bowel disease. The associated variants are correlated with expression changes in response to immune stimulus at two of these genes (ITGA4 and ITGB8) and at previously implicated loci (ITGAL and ICAM1). In all four cases, the expression-increasing allele also increases disease risk. We also identified likely causal missense variants in a gene implicated in primary immune deficiency, PLCG2, and a negative regulator of inflammation, SLAMF8. Our results demonstrate that new associations at common variants continue to identify genes relevant to therapeutic target identification and prioritization.
Assuntos
Predisposição Genética para Doença/genética , Doenças Inflamatórias Intestinais/genética , Integrinas/genética , Alelos , Estudo de Associação Genômica Ampla/métodos , Humanos , Inflamação/genética , Polimorfismo de Nucleotídeo Único/genética , Locos de Características Quantitativas/genéticaRESUMO
Primary sclerosing cholangitis (PSC) is a rare progressive disorder leading to bile duct destruction; â¼75% of patients have comorbid inflammatory bowel disease (IBD). We undertook the largest genome-wide association study of PSC (4,796 cases and 19,955 population controls) and identified four new genome-wide significant loci. The most associated SNP at one locus affects splicing and expression of UBASH3A, with the protective allele (C) predicted to cause nonstop-mediated mRNA decay and lower expression of UBASH3A. Further analyses based on common variants suggested that the genome-wide genetic correlation (rG) between PSC and ulcerative colitis (UC) (rG = 0.29) was significantly greater than that between PSC and Crohn's disease (CD) (rG = 0.04) (P = 2.55 × 10-15). UC and CD were genetically more similar to each other (rG = 0.56) than either was to PSC (P < 1.0 × 10-15). Our study represents a substantial advance in understanding of the genetics of PSC.
Assuntos
Colangite Esclerosante/genética , Doenças Inflamatórias Intestinais/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Alelos , Colite Ulcerativa/genética , Estudo de Associação Genômica Ampla/métodos , Humanos , Polimorfismo de Nucleotídeo Único/genética , RNA Mensageiro/genética , Fatores de RiscoRESUMO
Segmental duplications (SDs) comprise about 5% of the human genome and are enriched for immune genes. SD loci often show copy numbers variations (CNV), which are difficult to tag with genotyping methods. CNV in the Fcγ receptor region (FCGR) has been suggested to be associated with rheumatic diseases. The objective of this study was to delineate association of FCGR-CNV with rheumatoid arthritis (RA), coeliac disease and Inflammatory bowel disease incidence. We developed a method to accurately quantify CNV in SD loci based on the intensity values from the Immunochip platform and applied it to the FCGR locus. We determined the method's validity using three independent assays: segregation analysis in families, arrayCGH, and whole genome sequencing. Our data showed the presence of two separate CNVs in the FCGR locus. The first region encodes FCGR2A, FCGR3A and part of FCGR2C gene, the second encodes another part of FCGR2C, FCGR3B and FCGR2B. Analysis of CNV status in 4578 individuals with RA and 5457 controls indicated association of duplications in the FCGR3B gene in antibody-negative RA (P=0.002, OR=1.43). Deletion in FCGR3B was associated with increased risk of antibody-positive RA, consistently with previous reports (P=0.023, OR=1.23). A clear genotype-phenotype relationship was observed: CNV polymorphisms of the FCGR3A gene correlated to CD16A expression (encoded by FCGR3A) on CD8 T-cells. In conclusion, our method allows determining the CNV status of the FCGR locus, we identified association of CNV in FCGR3B to RA and showed a functional relationship between CNV in the FCGR3A gene and CD16A expression.
Assuntos
Artrite Reumatoide/genética , Doenças Inflamatórias Intestinais/genética , Receptores de IgG/biossíntese , Receptores de IgG/genética , Artrite Reumatoide/imunologia , Artrite Reumatoide/patologia , Variações do Número de Cópias de DNA/genética , Feminino , Proteínas Ligadas por GPI/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Humanos , Doenças Inflamatórias Intestinais/patologia , Masculino , Fenótipo , Polimorfismo de Nucleotídeo ÚnicoRESUMO
New insights into the underlying molecular pathophysiology of celiac disease (CeD) over the last few years have been guided by major advances in the fields of genetics and genomics. The development and use of the Immunochip genotyping platform paved the way for the discovery of 39 non-HLA loci associated to CeD, and for follow-up functional genomics studies that pinpointed new disease genes, biological pathways and regulatory elements. By combining information from genetics with gene expression data, it has become clear that CeD is a disease with a dysregulated immune response, which can probably occur in a variety of immune cells. This type of information is crucial for our understanding of the disease and for providing leads for developing alternative therapies to the current gluten-free diet. In this review, we place these genetic findings in a wider context and suggest how they can assist the clinical care of CeD patients.
Assuntos
Doença Celíaca/genética , Predisposição Genética para Doença/genética , Genótipo , HumanosRESUMO
Bacterial meningitis (BM) is a pyogenic infection present in the subarachnoid space, potentially fatal and frequently associated with neurological sequelae. During BM, cytokines (CTs) are locally produced. We sought to determine the CTs' clinical role as disease severity predictors in adults, which is not completely clear. Using a bead-based flow cytometric assay, levels of six CTs were determined in cerebrospinal fluid (CSF) and plasma from 18 adult BM patients and 19 uninfected controls. Long-term neurological sequelae were evaluated using the Glasgow Outcome Scale (GOS). All evaluated CTs were higher in CSF than in plasma, and the levels of CSF interleukin (IL)-6, IL-8, IL-10, IL-1ß, and tumor necrosis factor-α and plasma IL-10 and IL-12p70 were significantly higher in patients with severe sepsis than with sepsis, suggesting an association with clinical severity. There was a strong negative correlation between CSF IL-6 and plasma IL-12p70 with GOS score, supporting the possible role of these CTs in the development of neurological long-term sequelae. These findings could be helpful to identify candidates to receive neuroprotective treatments and early physiotherapy schemes.
RESUMO
Studies in European populations have contributed to a better understanding of the genetics of complex diseases, for example, in coeliac disease (CeD), studies of over 23 000 European samples have reported association to the HLA locus and another 39 loci. However, these associations have not been evaluated in detail in other ethnicities. We sought to better understand how disease-associated loci that have been mapped in Europeans translate to a disease risk for a population with a different ethnic background. We therefore performed a validation of European risk loci for CeD in 497 cases and 736 controls of north Indian origin. Using a dense-genotyping platform (Immunochip), we confirmed the strong association to the HLA region (rs2854275, P=8.2 × 10(-49)). Three loci showed suggestive association (rs4948256, P=9.3 × 10(-7), rs4758538, P=8.6 × 10(-5) and rs17080877, P=2.7 × 10(-5)). We directly replicated five previously reported European variants (P<0.05; mapping to loci harbouring FASLG/TNFSF18, SCHIP1/IL12A, PFKFB3/PRKCQ, ZMIZ1 and ICOSLG). Using a transferability test, we further confirmed association at PFKFB3/PRKCQ (rs2387397, P=2.8 × 10(-4)) and PTPRK/THEMIS (rs55743914, P=3.4 × 10(-4)). The north Indian population has a higher degree of consanguinity than Europeans and we therefore explored the role of recessively acting variants, which replicated the HLA locus (rs9271850, P=3.7 × 10(-23)) and suggested a role of additional four loci. To our knowledge, this is the first replication study of CeD variants in a non-European population.
Assuntos
Doença Celíaca/genética , População Branca/genética , Alelos , Proteínas de Transporte/genética , Mapeamento Cromossômico , Proteína Ligante Fas/genética , Loci Gênicos , Predisposição Genética para Doença , Técnicas de Genotipagem , Humanos , Índia , Ligante Coestimulador de Linfócitos T Induzíveis/genética , Subunidade p35 da Interleucina-12/genética , Isoenzimas/genética , Fosfofrutoquinase-2/genética , Polimorfismo de Nucleotídeo Único , Proteína Quinase C/genética , Proteína Quinase C-theta , Reprodutibilidade dos Testes , Fatores de Risco , Fatores de Transcrição/genética , Fatores de Necrose Tumoral/genéticaRESUMO
Although dietary gluten is the trigger for celiac disease, risk is strongly influenced by genetic variation in the major histocompatibility complex (MHC) region. We fine mapped the MHC association signal to identify additional risk factors independent of the HLA-DQA1 and HLA-DQB1 alleles and observed five new associations that account for 18% of the genetic risk. Taking these new loci together with the 57 known non-MHC loci, genetic variation can now explain up to 48% of celiac disease heritability.
Assuntos
Doença Celíaca/genética , Cadeias alfa de HLA-DQ/genética , Cadeias beta de HLA-DQ/genética , Estudos de Casos e Controles , Mapeamento Cromossômico , Estudos de Associação Genética , Predisposição Genética para Doença , Haplótipos , Humanos , Risco , Fatores de RiscoRESUMO
Type 1 diabetes (T1D) and celiac disease (CeD) cluster in families and can occur in the same individual. Genetic loci have been associated with susceptibility to both diseases. Our aim was to explore the genetic differences between individuals developing both these diseases (double autoimmunity) versus those with only one. We hypothesized that double autoimmunity individuals carry more of the genetic risk markers that are shared between the two diseases independently. SNPs were genotyped in loci associated with T1D (n=42) and CeD (n=28) in 543 subjects who developed double autoimmunity, 2,472 subjects with T1D only, and 2,223 CeD-only subjects. For identification of loci that were specifically associated with individuals developing double autoimmunity, two association analyses were conducted: double autoimmunity versus T1D and double autoimmunity versus CeD. HLA risk haplotypes were compared between the two groups. The CTLA4 and IL2RA loci were more strongly associated with double autoimmunity than with either T1D or CeD alone. HLA analyses indicated that the T1D high-risk genotype, DQ2.5/DQ8, provided the highest risk for developing double autoimmunity (odds ratio 5.22, P=2.25×10(-29)). We identified a strong HLA risk genotype (DQ2.5/DQ8) predisposing to double autoimmunity, suggesting a dominant role for HLA. Non-HLA loci, CTLA4 and IL2RA, may also confer risk to double autoimmunity. Thus, CeD patients who carry the DQ2.5/DQ8 genotype may benefit from periodic screening of autoantibodies related to T1D.