Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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.
 ...
PMID:A combination of HLA-DQ beta Asp57-negative and HLA DQ alpha Arg52 confers susceptibility to insulin-dependent diabetes mellitus. 231 83

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)
 ...
PMID:HLA DQA1-DQB1-TAP2 haplotypes in IDDM families: no evidence for an additional contribution to disease risk by the TAP2 locus. 758 84

To study the role of the HLA DQA1 gene and its interaction with DQB1 in the susceptibility of IDDM, subjects with insulin-dependent (type 1) diabetes mellitus and non-diabetic unrelated controls were recruited from a Chinese population living in northern Taiwan. HLA DQA1 exon 2 was enzymatically amplified by polymerase chain reaction. HLA DQA1 alleles were diagnosed by dot blotting and hybridization with 11 sequence-specific oligonucleotide probes. Among all the DQA1 alleles, DQA1*0301 and DQA1*0501 were more frequent while DQA1*0102, DQA1*0103 and DQA1*0601 were less frequent in Chinese with IDDM than in controls. Among the DQA1 genotypes, only DQA1*0301/0301 and DQA1*0301/0501 were associated with increased risk to IDDM while DQA1*0301/0601 and DQA1*0102/0103 were protective against IDDM in our population. As the cell surface HLA DQ molecules were formed from each DQA1 and DQB1 alleles either in cis- or trans-position, the numbers of susceptible HLA DQ alpha beta heterodimers were then derived from the genotypes of HLA DQA1/DQB1 in each person. The numbers of the possible diabetogenic DQ alpha beta dimers correlated with the degree of risk to IDDM (r = 0.92) but were not statistically significant (p > 0.05). Subjects with absence of diabetogenic HLA DQ molecules were resistant to developing IDDM while subjects with two or more forms of diabetogenic DQ molecules were associated with increased risk to IDDM. In conclusion, both DQA1 and DQB1 genes, which determine the formation of susceptible DQ alpha beta heterodimers, were significantly associated with IDDM in Chinese subjects living in Taiwan.
 ...
PMID:HLA DQA1 genotypes and its interaction with HLA DQB1 in Chinese IDDM living in Taiwan. 762 45

The incidence of insulin-dependent diabetes in individuals with cystic fibrosis is nearly 100 times greater than in the general population. In the latter group, strong associations with specific HLA DQA1 and DQB1 alleles have been observed. To determine if a similar distribution of alleles occurs in cystic fibrosis patients with diabetes, a cohort of these individuals was typed for DQA1 and DQB1 alleles. HLA DQB1*0201 (Asp57-) was more frequent in diabetics compared to controls (40.4 vs 28%), while the frequency of alleles encoding Asp57+ molecules was lower in diabetics relative to both the cystic fibrosis-only controls (P = 0.025) and the general population (P = 0.008). The presence of at least one protective DQA1-DQB1 heterodimer (i.e., Arg52- and Asp57+, respectively) in cis or trans was significantly lower in the diabetics than in either of the control groups. Thus, the HLA alleles known to be associated with insulin-dependent diabetes mellitus in the general population are also found in diabetics with cystic fibrosis.
 ...
PMID:Cystic fibrosis-related diabetes is associated with HLA DQB1 alleles encoding Asp-57- molecules. 788 62

DQCAR is a very polymorphic CA repeat microsatellite located between the HLA DQA1 and DQB1 gene. Previous studies have shown that specific DQCAR alleles are in tight linkage disequilibrium with known HLA DR-DQ haplotypes. Of special interest was the fact that haplotypes containing long CA repeat alleles (DQCAR > 111) were generally more polymorphic within and across ethnic groups. In these latter cases, several DQCAR alleles were found even in haplotypes containing the same flanking DQA1 and DQB1 alleles. In this work, three HLA class II associated diseases were studied using the DQCAR microsatellite. The aim of this study was to test if DQCAR typing could distinguish haplotypes with the same DRB1, DQA1 and DQB1 alleles in control and affected individuals. To do so, patients with selected HLA DR-DQ susceptibility haplotypes were compared with HLA DR and DQ matched controls. This included: Norwegian subjects with Celiac disease and the HLA DRB1*0301, DQA1*05011, DQB1*02 haplotype; Japanese subjects with Type 1 (insulin-dependent) Diabetes Mellitus and the HLA DRB1*0405, DQA1*0302, DQB1*0401 haplotype; and French patients with corticosensitive Idiopathic Nephrotic Syndrome and the HLA DRB1*0701, DQA1*0201, DQB1*0202 haplotype. These specific haplotypes were selected from our earlier work to include one haplotype bearing a short DQCAR allele (celiac disease and DR3,DQ2-DQCAR99) and two haplotypes bearing long DQCAR alleles (Diabetes Mellitus and DR4,DQ4-DQCAR 113 or 115 Idiopathic Nephrotic syndrome and DR7,DQ2-DQCAR 111-121). Additional DQCAR diversity was found in both control and patients bearing haplotypes with long CA repeat alleles. The results indicate that DQCAR typing did not improve specificity in combination with high resolution DNA HLA typing as a marker for these three disorders.
 ...
PMID:DQCAR microsatellite polymorphisms in three selected HLA class II-associated diseases. 856 Apr 48

Genetic markers may be used to improve the prediction of insulin-dependent diabetes mellitus (type 1) in individuals with islet autoantibodies. In order to develop a risk assessment strategy for the Lombardy region of northern Italy based on genetic and immunological markers, we analyzed HLA DQA1 and DQB1 alleles in 60 type 1 probands and their first-degree relatives and 65 unrelated control subjects from the same area using polymerase chain reaction (PCR) and oligonucleotide probes. The major risk haplotypes were DQA1 *0501-DQB1*0201 (39.1% of diabetic vs. 8.9% of non-diabetic haplotypes) and DQA1 *0301-DQB1*0302(20% of diabetic vs 7.1% of non-diabetic haplotypes). Stratified analysis showed DQA1*0102-DQB1*0502 also to be associated with type 1 susceptibility when found together with DQA1*0501-DQB1*0201 or DQA1*0301-DQB1*0302. One type 1 patient had the type 1-protective DQA1*0102-DQB1*0602 haplotype. Overall, 88% of patients and 20% of unrelated control subjects had either DQA1*0501-DQB1*0201 or DQA1*0301-DQB1*0302 in the absence of DQA1*0102-DQB1*0602. These data suggest that typing for markers identifying these three haplotypes in the Lombardy population will achieve a sensitivity of almost 90% and exclude 80% of children from subsequent islet autoantibody testing.
 ...
PMID:HLA-DQ screening for risk assessment of insulin dependent diabetes in northern Italy. 859 Jul 80

This study was designed to examine the hypothesis that some environmental factors increase the risk for insulin-dependent diabetes mellitus. Data on dietary history was collected from 80 diabetic children from the Santiago de Chile Registry and from 85 nondiabetic control subjects who were comparable in terms of age, sex, and ethnic characteristics. Early exposure was defined as the ingestion of food sources other than maternal milk before 3 months of age. To define genetic susceptibility to insulin-dependent diabetes mellitus each subject was typed in terms of HLA DQA1 and DQB1, and the possible conformation of susceptible heterodimers was considered as a risk marker. Fewer children were exclusively breast fed in the diabetic group than in the control group (21.55 +/- 15.05 vs 33.95 +/- 20.40 weeks, P<0.01). In addition, exposure to cow's milk and solid foods occurred earlier in the diabetic group than in the control group (15.90 +/- 10.95 vs 21.15 13.65 and 16.85 +/- 10.25 vs 21.20 +/- 12.35 weeks, P<0.05). Our data show that a short duration of breast-feeding and early exposure to cow's milk and solid foods may be important factors in the development of insulin-dependent diabetes mellitus. The high relative risk observed in individuals genetically predisposed indicates an interaction effect between genetic and environmental components.
 ...
PMID:Genetic predisposition and environmental factors leading to the development of insulin-dependent diabetes mellitus in Chilean children. 882 Apr 6

Hyperthyroidism of Graves' disease takes an unpredictable clinical course in the long-term follow-up. Whereas roughly 30-60% of patients relapse after their first antithyroid drug treatment, the likelihood of remission in the remaining group can not be foreseen. We have analysed-retrospectively-patients with Graves' disease that had been on antithyroid drug treatment for one year and were followed up thereafter. Patients were investigated for a variety of clinical parameters like ophthalmopathy status and relapse or remission as well as gene polymorphisms of the HLA and other regions. Of the 259 patients analysed so far, patients with ophthalmopathy did not differ from those without for HLA DQA1 and CTLA4 alleles tested. Also, the subgroup of patients with relapses after antithyroid drug treatment showed no different distribution of those alleles from the group with long-term remission. This study also confirms that the allele HLA DQA1* 0501 confers susceptibility to Graves' disease, furthermore, that the CTLA4-alanine 17 allele is an additional predisposing factor.
Exp Clin Endocrinol Diabetes 1996
PMID:Genetic markers in diagnosis and prediction of relapse in Graves' disease. 898 Oct 12

Considerable evidence exists that the genes coding for the HLA class II DQ molecules in the MHC region are major contributors to genetic susceptibility in insulin-dependent diabetes. Located centromeric to the DQ loci are the genes encoding DMA and DMB, two class II-like molecules which play an essential role in the pathway leading to antigen presentation by HLA class II. In this study we have examined the distribution of the DMB allele and studied HLA DQA1-DQB1-TAP2-DMB haplotypes in 52 IDDM families and 65 un-related controls. DMB allele frequencies in IDDM and control subjects were not significantly different. DMB*0101 was present in 85% of patients vs. 76% of controls, DMB*0102 in 12 vs. 17%, DMB*0103 in 3 vs. 5%, DMB*0104 in 0 vs. 2%. The IDDM-susceptible MHC DQA1-DQB1 haplotypes found by analysis of IDDM families were not associated with specific DMB alleles. We conclude that the described DMB polymorphisms are not associated with IDDM susceptibility and DMB genotyping is unlikely to improve the assessment of genetic risk for IDDM.
 ...
PMID:Lack of association of DMB polymorphism with insulin-dependent diabetes. 923 3

HLA DQA1, HLA DQB1 genes confer susceptibility to insulin-dependent (type 1) diabetes mellitus (IDDM). Since variants of their upstream regulatory regions are linked to the exons, we investigated their promoter polymorphisms (QAP and QBP) by a combination of PCR-based typing protocols in 136 IDDM patients, 167 controls and 6 families with an IDDM proband to identify possible additional susceptibility markers. Of major interest for IDDM susceptibility are the promoter "splits" of HLA DQA1*0301 (QAP3.1 and QAP3.2) and HLA DQB1*0302 (QBP3.2 and QBP3.3). QAP 3.1 (96% in patients vs 98% in controls) and QBP3.2 (100% vs 99%) were found to be the most frequent promoter variants for HLA DQA1*0301 and DQB1*0302, respectively, whereas QAP3.2 and QBP3.3 were very rare. Furthermore the promoter "splits" were equally distributed on the respective exon alleles in all groups and cosegregated in families as expected. In conclusion, HLA DQ-mediated susceptibility and protection in IDDM is not restricted to the exon but extends to the promoter region without further defining the genetic risk.
 ...
PMID:Highly polymorphic promoter regions of HLA DQA1 and DQB1 genes do not help to further define disease susceptibility in insulin-dependent diabetes mellitus. 945 18


1 2 Next >>