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)

Several studies provide evidence that in addition to the DQ-DR genes, HLA contains another uncharacterized gene or genes associated with type 1 diabetes. Our aim was to investigate the effect of this gene independently of the DQ-DR genes and to localize it with a matched case-control study. More than 1,400 patients and 30,000 control individuals from Finland were studied. They were first genotyped for the selected alleles of the HLA-DQB1, -DQA1, and -DRB1 genes. For the DR3/4(0404) genotype, 75 patients and 181 control subjects were stratified, and 241 patients and 354 controls were stratified for the DR3/4(0401) genotype. Ten microsatellite markers in the HLA class III and I regions (D6S273, TNFa, C12A, STR MICA, MIB, C125, C143, C245, C3211, and MOGc) and selected alleles of the HLA-A and HLA-B genes were studied. In the DR3/4(0404)-stratified group, we found that markers located between C12A and C143 near the HLA-B gene confer a strong additional diabetes association. This was confirmed by the population differentiation test in both DR3/4(0404)- and DR3/4(0401)-stratified groups. Our data indicate that an additional gene associated with type 1 diabetes is located in the 240-kb region near HLA-B. We excluded STR MICA polymorphism as a mutation responsible for diabetes association.
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PMID:Non-class II HLA gene associated with type 1 diabetes maps to the 240-kb region near HLA-B. 1111 29

The distribution of HLA class II alleles and genotypes in IDDM patients was examined in the three main Israeli ethnic groups: Ashkenazi Jews, non-Ashkenazi Jews, and Arabs. Molecular sequence specific oligonucleotide probe analysis was performed for DRB1, DQA1, and DQB1 genes. The DRB1*03011, DQA1*05 DQB1*02/DRB1*0402, DQA1*03, DQB1*0302 genotype was found to be the main susceptibility genotype in all three groups, with differences in the degree of association. In addition to DRB1*0402 (more frequent among Ashkenazi Jews), DRB1*0405, another subtype of DRB1*04, was found to be more prevalent among non-Ashkenazi Jews and Arabs. Many alleles were found to be negatively associated with insulin dependent diabetes mellitus (IDDM). This could be a result of the high frequency of susceptible alleles, or of linkage disequilibrium to a primary negatively associated allele. The strongest negative association was observed for DQB1*0301 in all three ethnic groups. The alleles DRB1*1401, DRB1*1501, DQB1*05031, DQB1*0602, and DQB1*0609 were not detected in any of the 202 IDDM patients, and are probably either strongly protective or in linkage with such alleles. Despite the differences found between the three ethnic groups, an overall analysis shows that the DRB1*04 alleles that account for susceptibility to IDDM in the Israeli population (DRB1*0402 and *0405) are the same as those responsible for susceptibility to IDDM in a number of other Mediterranean populations. In contrast, the susceptible allele in most Caucasian populations is DRB1*0401. It is noteworthy that the susceptible alleles DRB1*0402/05 for Mediterranean and DRB1*0401 for Caucasian populations are also frequent in the respective healthy populations. These findings support the results obtained in other studies, which point to a genetic relationship between the Israeli and Mediterranean populations.
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PMID:Immunogenetics of HLA class II in Israeli Ashkenazi Jewish, Israeli non-Ashkenazi Jewish, and in Israeli Arab IDDM patients. 1116 18

Type 1 diabetes mellitus is a common disease with a complex mode of inheritance. Its aetiology is underpinned by a major locus, insulin-dependent diabetes mellitus 1 (IDDM1) in the human leukocyte antigen (HLA) region of chromosome 6p21, and an unknown number of loci of lesser individual effect. In linkage analyses IDDM1 is a single peak, but it is evident that the linkage is caused by allelic variation of three adjacent genes in a 75 kb region, namely the class II genes, HLA-DRB1, -DQA1 and -DQB1. However, even these three genes may not explain all of the HLA association. We investigated, in the founder population of Sardinia, whether non-DQ/DR polymorphic markers within a 9.452 Mb region encompassing the whole HLA complex further influence the disease risk, after taking into account linkage disequilibrium with the disease loci HLA-DQB1, -DQA1 and -DRB1. We generalized the conditional association test, the haplotype method, to detect marker associations that are independent of the main DR/DQ disease associations. Three regions were identified as risk modifiers. These associations were not only independent of the polymorphic exon 2 sequences of HLA-DQB1, -DQA1 and -DRB1, but also independent of each other. The individual contributions of these risk modifiers were relatively modest but their combined impact was highly significant. Together, alleles of single nucleotide polymorphisms at the DMB and DOB genes, and the microsatellite locus TNFc, identified approximately 40% of Sardinian DR3 haplotypes as non-predisposing. This conditional analysis approach can be applied to any chromosome region involved in the predisposition to complex traits.
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PMID:Conditional linkage disequilibrium analysis of a complex disease superlocus, IDDM1 in the HLA region, reveals the presence of independent modifying gene effects influencing the type 1 diabetes risk encoded by the major HLA-DQB1, -DRB1 disease loci. 1128 54

The major histocompatibility complex (MHC) HLA region on chromosome 6p21 contains the major locus of type 1 diabetes (IDDM1). Common allelic variants at the class II HLA-DRB1, -DQA1, and -DQB1 loci account for the major part of IDDM1. Previous studies suggested that other MHC loci are likely to contribute to IDDM1, but determination of their relative contributions and identities is difficult because of strong linkage disequilibrium between MHC loci. One prime candidate is the polymorphic HLA-DPB1 locus, which (with the DPA1 locus) encodes the third class II antigen-presenting molecule. However, the results obtained in previous studies appear to be contradictory. Therefore, we have analyzed 408 white European families (200 from Sardinia and 208 from the U.K.) using a combination of association tests designed to directly compare the effect of DPB1 variation on the relative predisposition of DR-DQ haplotypes, taking into account linkage disequilibrium between DPB1 and the DRB1, DQA1, and DQB1 loci. In these populations, the overall contribution of DPB1 to IDDM1 is small. The main component of the DPB1 contribution to IDDM1 in these populations appears to be the protection associated with DPB1*0402 on DR4-negative haplotypes. We suggest that the HLA-DP molecule itself contributes to IDDM1.
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PMID:The HLA-DPB1--associated component of the IDDM1 and its relationship to the major loci HLA-DQB1, -DQA1, and -DRB1. 1133 27

It is known that certain combinations of alleles within the human leucocyte antigen (HLA) complex are associated with susceptibility or resistance to type 1 diabetes. Variable associations of DR and DQ with type 1 diabetes are documented in Caucasians but rarely in African populations; however, the role of HLA-DP genes in type 1 diabetes remains uncertain. In order to investigate the HLA class II associations with type 1 diabetes in Cameroonians, we used sequence-specific oligonucleotide probing (SSOP) to identify DRB1, DQA1, DQB1 and DPB1 alleles in 10 unrelated C-peptide negative patients with type 1 diabetes and 90 controls from a homogeneous population of rural Cameroon. We found a significantly higher frequency of the alleles DRB1*03 (chi2 = 17.9; P = 0.001), DRB1*1301 (chi2 = 37.4; P < 0.0001), DQA1*0301 (chi2 = 18.5; P = 0.001) and DQB1*0201 (chi2 = 37.4; P < 0.001) in diabetes patients compared to the control group. The most frequent alleles in the control population were DQA1*01, DQB1*0602 and DRB1*15. The DRB1*04 allele was not significantly associated with type I diabetes in our study population. We observed no significant difference between patients and controls in DPB1 allele frequency. In conclusion, the data in Cameroonian diabetes patients suggest the existence of HLA class II predisposing and specific protective markers, but do not support previous reports of a primary association between HLA-DP polymorphism and development of type I diabetes.
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PMID:HLA-DRB1, -DQA1, -DQB1 and DPB1 susceptibility alleles in Cameroonian type 1 diabetes patients and controls. 1153 22

We present a new sequence-based typing (SBT) strategy for the polymorphic HLA-DQA1 locus that is based on sequence-specific primer - polymerase chain reaction (SSP-PCR) amplification from genomic DNA. This method allows high-resolution genotyping in the second exon of the DQA1 gene. This gene presents a unique situation in which half of the known alleles contain an inframe three base pair deletion of codon 56. This deletion confounds direct SBT methodologies of heterozygous individuals containing both a deletion and nondeletion allele. The primary HLA haplotype associated with type 1 diabetes susceptibility is DR3/DR4. The DQA1 genotype for these two haplotypes are DQA1 *0501, a non-deletion allele and *0301, a deletion allele, thus creating a situation that cannot be resolved using a direct sequencing approach. Our group-specific SBT strategy isolates the deletion alleles from the nondeletion alleles, allowing them to be resolved by direct sequencing. Additionally, we present a novel spreadsheet program that accurately assigns the genotype of both homozygous and heterozygous persons.
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PMID:High-resolution sequence-based typing strategy for HLA-DQA1 using SSP-PCR and subsequent genotyping analysis with novel spreadsheet program. 1184 41

Type 1 (insulin-dependent) diabetes mellitus is associated with specific high-risk HLA DQ and DR haplotypes and islet cell antibodies. IDDM susceptibility in Caucasians is more strongly associated with DQ2/DQ8 (DQA1*0501-DQB1*0201/DQA1*0301-DQB1*0302) and DQ6 (B1*0604) than with DRB1*03/DRB1*04, while a single copy of DQ6 (B1*0602) gives sufficient protection against type 1 diabetes. As a part of the ABIS (All Babies in Southeast Sweden) study we have done typing of DQA1, DQB1, and DRB1 by polymerase chain reaction (PCR) amplification of the second exon of the genes, manually dot-blotting onto nylon membranes synthetic sequence-specific oligonucleotide (SSO) probes, 3' end-labeling with (32)P-dCTP, and hybridization followed by stringency washes and autoradiography using the SSO probe. Among 3756 newborns born in southeast Sweden we have found the high-risk genotype DQ2/DR3-DO8/DR4 to be present in 1%, haplotype DQ8/DR4 in 7.8%, and haplotype DQ2/DR3 in 9.6%. DQ2/DR3 or DQ8/DR4 was carried by 16.4% of newborns; the low-risk DQ6 molecule was carried by newborns as follows: DQ2/DR3-DQ6/DR15, 1.3%; DQ8/DR4-DQ6/DR15, 1.3%; and DQ6/DR15, 9.4%. We conclude from our results that the high incidence of IDDM in Sweden is at least in part due to increased prevalence of high-risk HLA haplotypes compared to protective haplotypes (20% vs. 13%) in the general population.
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PMID:Newborn screening for high-risk human leukocyte antigen markers associated with insulin-dependent diabetes mellitus: the ABIS study. 1202 Nov 31

IDDM is positively associated with HLA-DQA1*0301-DQB1*0302 (DQ8) and DQA1*0501-DQB1*0201 (DQ2) and negatively associated with DQA1*0102-DQB1*0602 (DQ6). The aim of the present study was to analyze the importance of several polymorphic residues and domains of DQalpha and DQbeta, in addition to residue 52 DQalpha and residue 57 DQbeta, with regard to susceptibility or resistance in new-onset 0- to 15-year-old Swedish children with IDDM (n = 425) and matched controls (n = 367). HLA genotyping identified several polymorphic residues of the DQalpha and DQbeta to be either positively or negatively associated with IDDM, including Arg 52 DQalpha and Asp 57 DQbeta. Leu 69 DQalpha was positively (OR 7.02, P < 0.0001), Ala 69 DQalpha was negatively (OR 0.22, P < 0.0001), Gln 47 DQalpha was positively (OR 5.8, P < 0.0001), Cys 47 DQalpha was positively (OR 2.2, P < 0.0001), Lys 47 DQalpha was negatively (OR 0.47, P < 0.005), and Arg 47 DQalpha was negatively (OR 0.22, P < 0.005) associated with IDDM. Similarly, residues at 11, 18, 45, 48, 50, 53, 55, 61, 64, 66, 76, and 80 were either positively or negatively associated with IDDM. Likewise, for DQbeta, Leu 53 DQbeta was positively (OR 11.01, P < 0.0001), Gln 53 DQbeta was negatively (OR 0.22, P < 0.0005), Arg 70 DQbeta was positively (OR 11.01, P < 0.0001), and Gly 70 DQbeta was negatively (OR 0.19, P < 0.0001) associated like other residues at 71, 74, 84, 85, 86, 89, and 90 DQbeta with IDDM. Certain domains in the DQalpha, RFTIL (at DQalpha positions 52, 61, 64, 66, and 69), were present in 95% of patients compared to 69% of controls (OR 9.01, P(c) < 0.0001), and DQbeta domain GR (at DQbeta positions 45 and 70) was present in 95% of patients and 68% of controls (OR 8.68, P < 0.0001), which correlated better than the individual amino acid residues with IDDM. A combination of the DQalpha and DQbeta chain domains was present in 94% of patients compared to 60% of controls (OR 10.6, P < 0.001). In conclusion, domains in the DQalpha, DQbeta, or both in the DQ molecule explain susceptibility or resistance to IDDM better than individual amino acid residues of DQA1 and DQB1.
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PMID:The combination of several polymorphic amino acid residues in the DQalpha and DQbeta chains forms a domain structure pattern and is associated with insulin-dependent diabetes mellitus. 1202 Nov 43

The most important gene loci defining risk of type 1 diabetes mellitus (T1DM) are located within the HLA gene region. HLA-DQ molecules are of primary importance but HLA-DR gene products modify the risk conferred by HLA-DQ. The risk associated with an HLA genotype is defined by the particular combination of susceptible and protective alleles. The highest risk is associated with a combination of two different risk haplotypes (7% risk to develop T1DM in Finland) whereas protective genotypes covering 69% of population have a risk of less than 0.2%). The complicated analysis of HLA genotypes is simplified by strong linkage disequilibrium between HLA-DRB1, -DQA1 and -DQB1 loci. In many cases one can deduce the alleles of other loci based on determination of the alleles in one locus. Differences between various populations in the frequency of marker alleles and in the linkages between them has to be taken into account. We have developed PCR based typing methods that utilize blood spot samples, microtiter plate format and lanthanide labeled oligonucleotide probes to define HLA-DQ and -DR alleles relevant for T1DM risk. Typing is run stepwise so that after initial HLA-DQB1 typing only those samples will be further analyzed in which -DQA1 or -DRB1 typing is informative and expected to contribute to the risk estimation. This method has been used to screen more than 50,000 newborn infants in Finland over a time period of 6 years, and it has been able to identify most children who have developed T1D during the follow-up period. The efficiency of the procedure has also been tested in Finnish and Greek populations.
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PMID:Estimation of genetic risk for type 1 diabetes. 1211 74

Diagnosis of autoimmune beta cell destruction by genetic risk analysis, autoantibody evaluation and the test of stimulated insulin secretion performance in first-degree relatives of diabetic patients. 208 Czech children and adults (101 boys and 107 girls, 186 siblings, 22 offspring of diabetic parents, aged 1-22 years, mean age 11.5 +/- 5.4 years) were enrolled in the study. Complete DQB1, DQA1 typing and DRB1*04 subtyping were performed by the PCR in 202 subjects. Sera of all children were investigated for anti-GAD65, anti-IA2 and insulin antibodies using RIA methods. The cut-off normal levels were determined as the 99th percentile of 105 non-diabetic children. IVGTT was performed in children with significant titre of one or more autoantibodies. Total level of stimulated insulin secretion < 48 mU/l was assessed as defect of FPIR. Risk genotype DQA1*05-DQB1*0201/DQA1*03-DQB1*0302 (OR = 100, CI 95% 13-730) was found in 24 of 202 first-degree relatives (12%). 22 children (11%) carried strong protective allele DQB1*0602 (OR = 0.03, CI 95% 0.01-0.12). Autoantibody positivity was recognised in 9 of 208 children (2.9%) and IVGTT was performed. Positivity of anti-GAD65, anti-IA2 or IAA was identified in 5 of 24 children with the highest risk genotype (21%) and in 4 children of 113 with lower risk or neutral genotypes (3.5%). Borderline positivity of one autoantibody was found in 1 boy with the highest risk genotype and in 2 children with lower risk genotypes. Only temporary anti-GAD65 positivity was found in girl with protective genotype. Type 1 diabetes mellitus was diagnosed in boy during IVGTT and disease manifested 6 months after IVGTT in girl with defect of FPIR. Standardised methods for prediction of Type 1 diabetes were introduced in first-degree relatives of diabetic patients. These methods are used for Czech registry of diabetic children.
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PMID:[Prediction of type 1 diabetes mellitus in first degree Czech relatives of diabetic patients]. 1213 48


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