Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

X-linked autoimmunity-allergic disregulation syndrome (XLAAD) is an X-linked recessive immunological disorder characterized by multisystem autoimmunity, particularly early-onset type 1 diabetes mellitus, associated with manifestations of severe atopy including eczema, food allergy, and eosinophilic inflammation. Consistent with the allergic phenotype, analysis of two kindreds with XLAAD revealed marked skewing of patient T lymphocytes toward the Th2 phenotype. Using a positional-candidate approach, we have identified in both kindreds mutations in JM2, a gene on Xp11.23 that encodes a fork head domain-containing protein. One point mutation at a splice junction site results in transcripts that encode a truncated protein lacking the fork head homology domain. The other mutation involves an in-frame, 3-bp deletion that is predicted to impair the function of a leucine zipper dimerization domain. Our results point to a critical role for JM2 in self tolerance and Th cell differentiation.
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PMID:JM2, encoding a fork head-related protein, is mutated in X-linked autoimmunity-allergic disregulation syndrome. 1116 Jan 29

Human chromosome Xp11.3-Xp11.23 encompasses the map location for a growing number of diseases with a genetic basis or genetic component. These include several eye disorders, syndromic and nonsyndromic forms of X-linked mental retardation (XLMR), X-linked neuromuscular diseases and susceptibility loci for schizophrenia, type 1 diabetes, and Graves' disease. We have constructed an approximately 2.7-Mb high-resolution physical map extending from DXS8026 to ELK1, corresponding to a genetic distance of approximately 5.5 cM. A combination of chromosome walking and sequence-tagged site (STS)-content mapping resulted in an integrated framework and transcript map, precisely positioning 10 polymorphic microsatellites (one of which is novel), 16 ESTs, and 12 known genes (RP2, PCTK1, UHX1, UBE1, RBM10, ZNF157, SYN1, ARAF1, TIMP1, PFC, ELK1, UXT). The composite map is currently anchored with 89 STSs to give an average resolution of approximately 1 STS every 30 kb. By a combination of EST database searches and in silico detection of UniGene clusters within genomic sequence generated from this template map, we have mapped several novel genes within this interval: a Na+/H+ exchanger (SLC9A7), at least two zincfinger transcription factors (KIAA0215 and Hs.68318), carbohydrate sulfotransferase-7 (CHST7), regucalcin (RGN), inactivation-escape-1 (INE1), the human ortholog of mouse neuronal protein 15.6, and four putative novel genes. Further genomic analysis enabled annotation of the sequence interval with 20 predicted pseudogenes and 21 UniGene clusters of unknown function. The combined PAC/BAC transcript map and YAC scaffold presented here clarifies previously conflicting data for markers and genes within the Xp11.3-Xp11.23 interval and provides a powerful integrated resource for functional characterization of this clonally unstable, yet gene-rich and clinically significant region of proximal Xp.
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PMID:An integrated, functionally annotated gene map of the DXS8026-ELK1 interval on human Xp11.3-Xp11.23: potential hotspot for neurogenetic disorders. 1194 89

Immune-mediated tissue destruction or disregulation is the cause of multiple common, as well as rare, endocrine disorders including type 1 diabetes, Graves' disease, Hashimoto thyroiditis, and Addison's disease. Each of these disorders can be divided into a series of stages beginning with genetic susceptibility, environmental triggering events, and active autoimmunity, followed by metabolic abnormalities with overt disease. Common genetic susceptibility is suggested by the clustering of a series of disorders in the same individual and his or her family. A major portion of the genetic susceptibility lies in the HLA region, but for several disorders, mutation of transcription factors underlies disease susceptibility (eg, X-linked polyendocrinopathy, immune deficiency and diarrhea, and autoimmune polyendocrine syndrome type 1). With improving immunogenetic and pathogenic understanding, type 1A diabetes is now predictable, and excellent autoantibody screening assays are available. This knowledge, combined with studies in animal models, has led to trials for the prevention of diabetes. In addition, aberrant immunologic reactions (eg, insulin autoantibodies after insulin therapy, Graves' disease after monoclonal anti-T-cell therapy in multiple sclerosis) can complicate standard and experimental therapies. We therefore believe that an understanding of the immunogenetics and immunopathogenesis of endocrine disorders can aid in the prevention of morbidity and mortality for these related diseases.
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PMID:17. Immunologic endocrine disorders. 1259 8

Mutations of the forkhead/winged helix transcription factor FOXP3 gene on chromosome Xp11.23 cause a rare recessive monogenic disorder called IPEX (immune dysregulation, polyendocrinopathy, including type 1 diabetes, enteropathy, and X-linked syndrome). FOXP3 is necessary for the differentiation of a key immune suppressive subset of T-cells, the CD4+CD25+ regulatory T-cells. Previously, we reported a significant male-female bias in the common, multifactorial form of type 1 diabetes in Sardinia and evidence of linkage of chromosome Xp11 to the disease. These findings indicate that FOXP3 is a prime functional and positional candidate locus for the common form of type 1 diabetes. In the present study, we initially scanned 82 kb of the FOXP3 region for common polymorphisms, including sequencing all of the coding and functionally relevant portions of the gene in 64 Sardinian individuals. Then the most informative polymorphisms in 418 type 1 diabetic families and in 268 male case and 326 male control subjects were sequentially genotyped and tested for disease association. There is no evidence that variants in the FOXP3 regions analyzed are associated with type 1 diabetes and account for the male-female bias observed in Sardinia. Our data indicate that allelic variation in or near the coding regions of the FOXP3 gene does not have a major role in the inherited susceptibility to the common form of type 1 diabetes.
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PMID:No association between variation of the FOXP3 gene and common type 1 diabetes in the Sardinian population. 1522 Feb 19

IPEX syndrome is a genetic autoimmune disease characterized by immune-mediated polyendocrinopathy, enteropathy, and X-linked inheritance. We describe a case of IPEX in which lymphocyte phenotypes were assessed at birth, before initiation of Cyclosporin A therapy, and at frequent intervals to 18 months of age. We performed flow cytometry for lymphocyte subtypes and for activation markers (HLA-DR, CD25, and CD69 or CD71). The ratios of both T to B cells and CD4+ to CD8+ cells were elevated at birth, but CD4+ cells were not activated. HLA-DR+ and CD25+ activated T-cells increased in association with two episodes of clinical deterioration: colitis and the onset of type I diabetes mellitus. These results indicate that measures of activation, particularly HLA-DR+ and CD25+ frequency, correlate well with the development of early active disease and may presage clinical episodes. Continuous maintenance of immunosuppression, once started, appears critical for prevention of permanent tissue damage.
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PMID:Prospective immunological profiling in a case of immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX). 1527 Aug 55

The heterozygous combination of DQA1*03-DQB1*0302 (DQ8) and DQA1*05-DQB1*0201 (DQ2) confers the highest known HLA-DQ-linked risk for type 1 diabetes, suggesting a role for transcomplementation. The trans-heterodimer encoded by DQA1*03 and DQB1*02 is also rarely observed in cis in whites. Islet antibody-positive diabetic patients (P; n = 2,238) and control subjects (C; n = 2,223) of white descent were genotyped by a HLA-DQA1-DQB1 dot-blot method. The presence of the DQA1*03-DQB1*02 haplotype was observed in 22 patients (1%) versus 6 controls (0.3%) (odds ratio [OR] = 3.7, p = 0.005). It was more prevalent in whites of Northern African descent, but both in European (n = 3,813) and in Northern African whites (n = 648), the DQA1*03-DQB1*02 haplotype tended to be associated with diabetes (respectively, P 0.3% vs. C 0.03%, OR = 12.2, p = 0.005; and P 2.1% vs. C 0.6%, OR = 3.8, p = 0.03). DRB1 typing revealed that DQA1*03-DQB1*02 is usually associated with the DRB1*0405 risk allele in European patients and with DRB1*0405, DRB1*07 and DRB1*09 in Northern African whites. Like in DQ2/DQ8-positive patients, the presence of DQA1*03-DQB1*02 is preferentially associated with younger age at clinical onset than in other genotypes, but unlike in subjects carrying DQ2/DQ8, earlier clinical manifestation was mostly restricted to male subjects, often carrying DR3 and/or DQB1*02 on the other chromosome. These results are compatible with an effect of cis-encoded heterodimers or with previously suggested interactions of X-linked genetic factors with (DR3-)DQB1*02 haplotypes.
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PMID:The rare HLA-DQA1*03-DQB1*02 haplotype confers susceptibility to type 1 diabetes in whites and is preferentially associated with early clinical disease onset in male subjects. 1530 63

Immunodysregulation, Polyendocrinopathy, Enteropathy, X-linked (IPEX) syndrome is a rare inborn error of immune regulation characterized by the early onset of one or more autoimmune diseases in boys. IPEX is caused by mutations in FOXP3, and is thus the homologue of the scurfy mutant mouse. The gene product, Scurfin, is required for the development of CD4+CD25+ T regulatory cells. In the absence of T regulatory cells, activated CD4+ T cells instigate multi-organ damage resulting in type 1 diabetes, enteropathy, eczema, hypothyroidism, and other autoimmune disorders. While effective therapies are currently limited, studies in the scurfy mouse are revealing aspects of pathophysiology and genetics that will lead to novel approaches for treating IPEX and other autoimmune disorders. Females carrying Foxp3 mutations are unaffected. In new experiments we show that female scurfy mice that are also heterozygous in trans for the X-linked recessive common gamma chain knockout contract autoimmune disease, proving that murine Foxp3 is subject to X-inactivation and providing an example of gene-gene interaction causing autoimmune disease in females. One explanation for the lesser disease severity in these females is proposed.
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PMID:IPEX and FOXP3: clinical and research perspectives. 1624 87

Adaptive regulatory T cells that develop from naive CD4 cells in response to exposure to Ag can act as immunotherapeutic agents to control immune responses. We show that effectors generated from murine islet-specific CD4 cells by TCR stimulation with IL-2 and TGF-beta1 have potent suppressive activity. They prevent spontaneous development of type 1 diabetes in NOD mice and inhibit development of pancreatic infiltrates and disease onset orchestrated by Th1 effectors. These regulatory T cells do not require innate CD25+ regulatory cells for generation or function, nor do they share some characteristics typically associated with them, including expression of CD25. However, the adaptive population does acquire the X-linked forkhead/winged helix transcription factor, FoxP3, which is associated with regulatory T cell function and maintains expression in vivo. One mechanism by which they may inhibit Th1 cells is via FasL-dependent cytotoxicity, which occurs in vitro. In vivo, they eliminate Th1 cells in lymphoid tissues, where Fas/FasL interactions potentially play a role because Th1 cells persist when this pathway is blocked. The results suggest that adaptive regulatory CD4 cells may control diabetes in part by impairing the survival of islet-specific Th1 cells, and thereby inhibiting the localization and response of autoaggressive T cells in the pancreatic islets.
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PMID:Adaptive islet-specific regulatory CD4 T cells control autoimmune diabetes and mediate the disappearance of pathogenic Th1 cells in vivo. 1658 66

Immunodysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare disorder caused by mutations in the FOXP3 gene that result in the defective development of CD4+CD25+ regulatory T cells which constitute an important T cell subset involved in immune homeostasis and protection against autoimmunity. Their deficiency is the hallmark of IPEX and leads to severe autoimmune phenomena including autoimmune enteropathy, dermatitis, thyroiditis, and type 1 diabetes, frequently resulting in death within the first 2 years of life. Apart from its clinical implications, IPEX illustrates the importance of immunoregulatory cells such as CD4+CD25+ regulatory T cells.
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PMID:IPEX as a result of mutations in FOXP3. 1831 33

Autoimmunity is mediated by a variety of mechanisms, molecular and cellular events, and responses. Predisposition to a given autoimmune response requires the requisite allele(s) that controls antigen presentation by antigen-presenting cells for T cell recognition. Some autoimmune responses emerge following infection by a pathogen, whose protein(s) possess structural similarities in some of its epitopes to regions on proteins of the host. Thus, antibodies evoked against a pathogen might cross-react with a self-protein and act as autoantibodies, and the involved autoantigen then provides a source for persistent stimulation. Proteins to which the immune system is ordinarily self-tolerant might, if altered, elicit autoimmune responses. Ways in which self-proteins can be altered include mutations and altered expression, posttranslational modification, covalent modifications, denaturation, native disorder or misfolding. Sequestered proteins normally sheltered from immune recognition become immunogenic and targets of immune effector functions, once exposed to the immune system. Other alterations can occur because of disruption in the levels or activity of regulatory proteins. These include certain alleles of the cytotoxic T lymphocyte-associated antigen-4 gene (possibly a nonspecific exacerbating molecule of disease risk in several autoimmune diseases), the lymphoid protein tyrosine phosphatase nonreceptor type 22 gene (associated with type 1 diabetes and other autoimmune diseases), TNF-alpha (involved in chronic inflammation, autoimmunity and malignancies) and the FOXP3 gene (expressed by CD4+C25+ regulatory T cells), whose mutations can cause immune dysregulation, polyendocrinopathy and X-linked inheritance syndromes of systemic autoimmunity. An autoimmune response can also arise from natural antibodies or autoantibodies that occur independently of known immunization and are able to bind to microbial antigens, altered proteins as well as self-antigens. Natural autoantibodies possess in general a low intrinsic affinity for antigen, but can function as templates for the generation of pathogenic autoantibodies, that emerge through a process of clonal selection entailing somatic hypermutation and class switch DNA recombination, as driven by antigen.
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PMID:Molecular mechanisms of autoimmunity. 1832 81


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