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)

Analysis of the frequencies of class II HLA-DR and HLA-DQ alleles by serological and DNA typing in 49 Japanese patients with type 1 (insulin-dependent) diabetes and 31 Japanese controls indicates the following. (i) Susceptibility is more strongly associated with the HLA-DQ subregion than with the HLA-DR subregion. (ii) Of the class II alleles detected, the A3 allele of the DQA1 locus was the most strongly associated with disease. Ninety-six percent of the patients were positive for the A3 allele compared to 53% of the controls (P = 0.001; relative risk = 19.7; confidence limits = 3.72-188.64). (iii) The DQw8 allele of the DQB1 locus, which is associated with susceptibility to type 1 diabetes in Caucasians and Blacks, was not increased in frequency in Japanese patients (22%) versus controls (19%). (iv) Asp-57-encoding DQB1 alleles are associated with reduced susceptibility to type 1 diabetes in Caucasians. The major predisposing haplotypes in Japanese are DR4 and DR9. By DNA sequence analysis, both of these Japanese haplotypes have Asp-57-encoding DQB1 alleles. Oligonucleotide dot blot analysis showed that all, except 1, of the 49 Japanese patients and all of the 31 controls have at least one Asp-57-encoding DQB1 allele. In addition, 40% of the patients were homozygous for Asp-57-encoding DQB1 alleles versus 35% of the controls. The high frequencies of Asp-57-encoding DQB1 alleles in this ethnic group may account for the rarity of type 1 diabetes in Japan.
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PMID:The A3 allele of the HLA-DQA1 locus is associated with susceptibility to type 1 diabetes in Japanese. 230 May 72

Family and population studies indicate that predisposition to insulin-dependent (type I) diabetes mellitus (IDDM) is polygenic. It has been shown that the absence of the aspartic acid in position 57 (Asp57) of the DQ beta chain is positively correlated to IDDM. However, Asp57-negative haplotypes do not always confer susceptibility and conversely, some Asp57-positive haplotypes seem to be disease associated. It has been suggested that other HLA class II sequences, probably belonging to the HLA DQA1 gene, confer susceptibility to IDDM. This report, based on extensive oligonucleotide dot blot hybridization of PCR-amplified DQA1 and DQB1 genes, reinforces the importance of the Asp57-negative DQ beta chain, but also introduces the possibility that a DQ alpha chain bearing an arginine in position 52 (Arg52) confers susceptibility to IDDM. A molecular model of susceptibility to IDDM is proposed. This model strongly suggests that the disease susceptibility correlates quantitatively with the expression at the cell surface of a heterodimer, composed of a DQ alpha-chain bearing an Arg52 and a DQ beta chain lacking an Asp57. In view of the respective positions of the two residues and their charge, we might anticipate that both residues DQ beta Asp57 and DQ alpha Arg52 are critical for modulation of susceptibility, presumably via viral-antigenic peptide and/or autoantigen presentation.
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PMID:A combination of HLA-DQ beta Asp57-negative and HLA DQ alpha Arg52 confers susceptibility to insulin-dependent diabetes mellitus. 231 83

INSULIN-dependent (type I) diabetes mellitus (IDDM) follows an autoimmune destruction of the insulin-producing beta-cells of the pancreas. Family and population studies indicate that predisposition is probably polygenic. At least one susceptibility gene lies within the major histocompatibility complex and is closely linked to the genes encoding the class II antigens, HLA-DR and HLA-DQ (refs 3, 4). Fine mapping of susceptibility genes by linkage analysis in families is not feasible because of infrequent recombination (linkage disequilibrium) between the DR and DQ genes. Recombination events in the past, however, have occurred and generated distinct DR-DQ haplotypes, whose frequencies vary between races. DNA sequencing and oligonucleotide dot-blot analysis of class II genes from two race-specific haplotypes indicate that susceptibility to IDDM is closely linked to the DQA1 locus and suggest that both the DQB1 (ref. 7) and DQA1 genes contribute to disease predisposition.
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PMID:Identification of susceptibility loci for insulin-dependent diabetes mellitus by trans-racial gene mapping. 249 58

The majority of the genetic component in insulin dependent (Type 1) diabetes mellitus can be explained by associations with genes on short arm of chromosome 6 located in the major histocompatibility complex. With the advent of cloning of the HLA Class II region genes it has been possible to refine the previous known association of HLA-DR3 and DR4 with this disease. Strong associations of IDDM have now been shown to exist with the DQB1 gene and/or linked genes, although this does not completely explain the HLA susceptibility to this disease.
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PMID:The major histocompatibility complex and insulin dependent (type 1) diabetes. 257 93

The present knowledge of the HLA system and its biological function is summarized as a basis for the subsequent discussion of the associations between this system and insulin-dependent diabetes (IDDM) and some mechanisms that may explain them. Although the serologically detectable DR determinants are still the most handy markers, there is now increasing evidence from studies of restriction enzyme fragment length polymorphism (RFLP) in IDDM that DQ determinants may play a primary role in causing susceptibility and/or resistance to this disease. Thus, it is now evident that about 90% of DR4-positive diabetics carry the DQw8 determinant present in only about 65% of DR4-positive controls. Most recently, it has been claimed that an aspartic acid in position 57 of the DQB1 (DQ-beta-1) chain confers resistance to IDDM. Although this may be true, it does not explain the disproportionate decrease of DR2 or the particularly high risk of DR3/4 heterozygotes, which is still good evidence that several HLA genes are involved. Because Class II antigens show the strongest associations, the most plausible hypothesis about the mechanism(s) involves specific presentation of as yet unknown antigenic peptides to T-helper lymphocytes, which may induced the formation of both anti-islet cell antibodies and T-cytotoxic lymphocytes capable of destroying beta cells. However, T-suppressor lymphocytes also may be involved. If this hypothesis is correct, the most urgent task is to define the antigenic peptides in question, whether they are environmental (e.g., viral) or autologous.
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PMID:HLA and insulin-dependent diabetes: an overview. 265 26

Sequence variation among HLA class II promoter elements may contribute to functional differences in transcriptional regulation of different class II alleles. In addition to influencing the binding sites for nuclear transcription factors, promoter polymorphism may also alter intrinsic structural properties of the DNA strands, such as conformation and curvature, which influence the formation of stable transcription complexes. We used SSCP analysis of PCR-amplified promoter regions from the DQB1 locus to evaluate conformational polymorphism within DQ alleles. Distinct electrophoretic migration patterns of the SSCP products were detected for six DQB1 alleles; analysis of the DQB1*0302 promoter, known to be associated with type 1 diabetes, showed no SSCP differences between IDDM patients and normal controls. Using computer modeling based on a "nearest-neighbor" energy of predicted curvature theory, we examined the effect of allelic promoter region sequence polymorphism on the predicted curvature of double-stranded DNA, and found distinct allelic differences in predicted DNA curvature, both in transcriptional consensus binding sites and in regions located between binding sites. These data are consistent with a model in which intrinsic sequence variation in the promoter region results in ultrastructural differences which may influence DNA bending and interactions with multimeric DNA-protein transcription complexes.
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PMID:Ultrastructural allelic variation in HLA-DQB1 promoter elements. 749 72

The contribution of genetic variation at HLA class II loci to the susceptibility to and protection from IDDM was investigated by analyzing the distribution of HLA-DRB1*04 haplotypes in 630 Sardinian newborns and 155 Sardinian IDDM patients. The different RRs and ARs of the various DR4-DQB1*0302 haplotypes, significantly ranging from the strongly associated DRB1*0405, DQB1*0302 to the protective DRB1*0403, DQB1*0302 haplotypes, provides clearcut evidence that the DRB1 locus is crucial in conferring IDDM predisposition or protection. Also, the DQB1 locus influences IDDM predisposition or protection by restricting the disease-positive association to DRB1*0405 haplotypes carrying the susceptibility DQB1*0302 or DQB1*0201 alleles but not the protective DQB1*0301 allele. Haplotype analysis not only suggests that the DRB1 and DQB1 loci influence IDDM risk in the same way, but also that the HLA-linked protection is "dominant" compared with "susceptibility." These results, obtained from a population with one of the highest IDDM incidences in the world, define more clearly the contribution of the various HLA loci to IDDM protection or susceptibility and allow a more precise calculation of AR.
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PMID:The distribution of DR4 haplotypes in Sardinia suggests a primary association of type I diabetes with DRB1 and DQB1 loci. 749 78

IDDM is known to be associated with genes of HLA complex, particularly alleles of HLA-DQ. The 40-kb TAP gene complex is located approximately 150 kb centrometric to the DQB1 locus. The TAP1-TAP2 protein heterodimer is required for normal expression levels of class I, molecules on the surface of cells. While present evidence implicates HLA-DQ as the major susceptibility locus in IDDM, as class I expression apparently plays a role in the progression of disease, the possibility exists that the association attributed to HLA-DQ is in fact due to an association with the TAP genes. Several studies have concluded that the alleles of TAP1 are not significantly associated with IDDM; this report concentrates on the more telomeric TAP2 locus. During this investigation, six previously described TAP2 alleles were identified in 208 normal Caucasians and 241 Caucasian diabetics. Sequence analysis of cDNA clones identified a seventh allele of TAP2, TAP2*F, which contains an arginine-to-cystine interchange at amino acid position 651. Overall, our results indicate only a modest association of IDDM with TAP2; however, the newly described TAP2*F allele was found to be significantly increased in a modest subset of our large diabetic population. These data, generated from the same population of controls and diabetics we previously studied at all other relevant MHC loci, provide additional evidence that the HLA susceptibility to IDDM maps to HLA-DQ.
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PMID:TAP2 association with insulin-dependent diabetes mellitus is secondary to HLA-DQB1. 755 30

The TAP2 gene, located in the HLA class II region, encodes a subunit of a transporter involved in the endogenous antigen-processing pathway, and has been suggested to contribute to the genetic risk for insulin-dependent diabetes (IDDM). In order to determine whether the TAP2 locus modulates the risk conferred by HLA DQ loci, HLA DQA1-DQB1-TAP2 haplotypes were analysed in 48 IDDM probands, their first degree relatives, and in 62 normal control subjects. A decreased frequency of the TAP2B allele was confirmed in this IDDM cohort (12 vs 28% in control subjects, pc < 0.05). Analysis of 73 informative meiotic events in IDDM and control families demonstrated a recombination fraction between HLA DQB1 and TAP2 loci of 0.041 (Log of the odds score = 16.5; p < 10(-8)) indicating strong linkage between these loci. Family haplotype analysis demonstrated linkage disequilibrium between TAP2 and HLA DQA1-DQB1, and showed that the reduced frequency of TAP2B was associated with its absence on the IDDM susceptible DQA1*0301-DQB1*0302 haplotype, its low frequency on DQA1*0501-DQB1*0201, and the association of TAP2B with DQA1*0101-DQB1*0501 haplotypes which were less frequent in IDDM patients. Comparison of transmitted with non-transmitted haplotypes in IDDM families showed a slight but not significant decrease in TAP2B allele frequency on transmitted (3 of 37) vs non-transmitted (2 of 9) HLA DQA1*0501-DQB1*0201 haplotypes. No other differences were observed. Twenty-four unrelated DQA1*0501-DQB1*0201 haplotypes from non-diabetic families had a TAP2B allele frequency (4%) similar to that in IDDM haplotypes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:HLA DQA1-DQB1-TAP2 haplotypes in IDDM families: no evidence for an additional contribution to disease risk by the TAP2 locus. 758 84

Because particular human leukocyte antigen (HLA) DQ alleles are the major predisposing factors for type 1 diabetes mellitus (IDDM), we investigated whether they are shared by other endocrine autoimmune diseases. We, therefore, analyzed the HLA DQ genotypes of 171 patients with IDDM, 271 with Graves' disease (GD), 65 with Hashimoto's thyroiditis, 51 with postpartum thyroiditis, 53 with Addison's disease (AD), and 271 healthy controls. HLA DQA1 and DQB1 alleles were defined by polymerase chain reaction and sequence-specific oligonucleotide hybridization as well as by single strand conformational polymorphism analysis. HLA DQA1*0501 was significantly more frequent in IDDM (60%), GD (65%), and AD (70%) than in controls (43%); DQA1*0301 was significantly more frequent only in IDDM (67% vs. 30% controls). The heterozygous state DQA1*0301/*0501 was found in 9% of controls and 35% of IDDM (relative risk, 5.6). An arginine at position 52 on either DQA1 allele was significantly more frequent in patients with IDDM (94%), GD (80%), and AD (89%) compared with controls (66%). HLA DQB1*0201 and DQB1*0302 were more frequent in IDDM patients (*0201, 62% vs. 36% in controls, *0302, 59% vs. 19% controls), whereas DQB1*0602 was less frequent in IDDM (4%) and GD (18% vs. 31% of controls). In conclusion, endocrine autoimmunity has a common immunogenetic background; susceptibility is conferred by DQA1*0501 as well as an arginine at position 52 of DQA1 alleles, and protection against IDDM and GD is conferred by DQB1*0602.
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PMID:Susceptibility and resistance alleles of human leukocyte antigen (HLA) DQA1 and HLA DQB1 are shared in endocrine autoimmune disease. 760 64


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