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)

Insulin-dependent diabetes mellitus (IDDM) in Caucasians is strongly associated with HLA-DR3-DQ2 and DR4-DQ8. In order to investigate the HLA class II associations with IDDM in Algerians, we have used polymerase chain reaction (PCR) and sequence specific oligonucleotide analysis (SSO) to identify DQA1, DQB1, and DRB1 alleles, haplotypes and genotypes in 50 unrelated IDDM patients and 46 controls from a homogeneous population in Western Algeria. Both DRB1*0301-DQA1*0501-DQB1*0201 (DR3-DQ2) and DRB1*04-DQA1*0301-DQB1*0302 (DR4-DQ8) haplotypes were found at increased frequencies among the patients compared to controls (45% vs. 13%, RR = 5.5, Pc < 10(-5) and 37% vs. 4%, RR = 12.9, Pc < 10(-4), respectively). Among the latter, in contrast to other Caucasian populations, only DRB1*0405-DQA1*0301-DQB1*0302 was significantly increased in the Algerian patients (25% vs. 1% in controls, RR = 30.3, Pc < 10(-3). Accordingly, the highest risk of disease was observed in DRB1*0301-DQA1*0501-DQB1*0201/DRB1*0405-DQA1+ ++*0301-DQB1*0302 heterozygotes (34% in patients vs. 0% in controls; RR = 49; Pc < 10(-3). This observation and its comparison with DR-DQ haplotypes in other ethnic groups suggest that the DRB1*0405 allele which encodes an Asp57-negative beta chain may contribute to IDDM susceptibility in a similar way as Asp57-negative DQ beta chains.
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PMID:The HLA-DRB1*0405 haplotype is most strongly associated with IDDM in Algerians. 147 90

Insulin dependent diabetes mellitus (IDDM) is known to associate with various antigens and alleles of the HLA-system: DR3, DR4, and DQ-determinants. However penetration of the HLA-genes, predisposing to disease, is low, suggesting a possible role of additional genes outside the HLA-system in IDDM development. Among such genes there can be a group of heavy chain Ig genes (the Gm-system). The frequency of antigens of the Gm-system C1m(1) and C1m(2) and antigens of loci A, B, C and DR of the HLA-system was investigated in 92 Russians divided into 3 groups: 1 - IDDM patients from nuclear families (n = 35); 2 - their relatives of the 1st degree of kinship (n = 34); 3 - a random sampling (n = 23). The results obtained by A. A. Lopatenok and O. S. Budyakov (1973) were used as control data. No significant difference (p greater than 0.05) was found while comparing the frequency of Gm-phenotypes in IDDM patients from nuclear families with DR 4/X and in IDDM patients from nuclear families with another DR-phenotype, nor any significant difference was noted while comparing the frequency of Gm-phenotypes in IDDM patients from nuclear families and in patients from a random sampling with the HLA-phenotype DR 4/X. Thus the relationship of the Gm-system with IDDM through interrelationship with the HLA-DR-genes was undetectable. A conclusion was made that factors of the Gm-system played no significant role in predisposition to IDDM and could not be used as its genetic markers.
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PMID:[Probability of an association between HLA- and DR-antigens in nuclear families of patients with insulin-dependent diabetes mellitus]. 151 80

Insulin-dependent diabetes mellitus (IDDM) in whites is strongly associated with particular HLA-DQ alpha beta heterodimers composed of a DQ alpha chain with an arginine at residue 52 (Arg52+) combined to a DQ beta chain lacking an aspartic acid at residue 57 (Asp57-). With the aim of confirming this association, clarifying which heterodimers account for the highest risk of IDDM and explaining the excess risk of DR3-DQw2/DR4-DQw8, 115 unrelated white IDDM patients and 108 unrelated healthy nondiabetic control subjects were studied. With polymerase chain reaction and sequence-specific oligonucleotide probes, both patients and control subjects were typed for their HLA-DQA1 and DQB1 alleles and their DQA1-DQB1 haplotype and genotype frequencies were compared. Four major findings emerged from our analysis. 1) Arg52+ DQ alpha/Asp57- DQ beta heterodimers, formed in cis and/or in trans, are strongly associated with susceptibility to IDDM; 97% of patients and 46% of control subjects had at least one such susceptibility heterodimer (relative risk [RR] 32, confidence interval [Cl] 14.25-71.86, P less than 10(-7). 2) The degree of disease susceptibility depends on the number of such DQ heterodimers that a subject can express according to his or her DQA1-DQB1 genotype. The highest RR was observed in patients with four susceptibility DQ heterodimers (RR 41, Cl 17.05-95.9). 3) Only part of the susceptibility DQ heterodimers were significantly increased in patients, conferring IDDM susceptibility of different strength. The strongest association was with the DQA1*0501-DQB1*0302 combination formed in trans position (RR 35.2, CI 12.88-96.78, P less than 10(-7).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Dose effect of cis- and trans-encoded HLA-DQ alpha beta heterodimers in IDDM susceptibility. 155 98

Susceptibility to IDDM is strongly associated with HLA. Some HLA allelic combinations (haplotypes) can be found in most patients, whereas other haplotypes are encountered only rarely. It has been proposed that this difference in susceptibility depends on the absence (in the DR3 and DR4 haplotypes) or the presence (in the DR2 haplotype) of Asp57 in the DQ beta-chain. Data on southern European populations challenge this hypothesis because the DR2 haplotype has not been associated negatively with IDDM, as reported in northern European populations. This study on a selected panel of DR2-positive Italian IDDM patients shows that 19 of 21 (90.5%) DR2 haplotypes possess a non-Asp57 DQB allele. Moreover, the same non-Asp57 subtype has a comparatively high frequency (9/28, or 32.1%, DR2 haplotypes) also in the DR2-positive healthy Italian population. The difference between patients and control subjects is significant (P less than 0.0001). This is the largest series of DR2-positive patients analyzed so far. Comparison with cumulated data in various white populations shows a distinct northern European-to-southern European gradient. Toward southern Europe, the relative frequency of the non-Asp57 DR2 subtype increases. Concomitantly, the apparent protective effect of the DR2 haplotype disappears. Therefore, the observed differences in DR2-IDDM association in white populations can be explained adequately by the Asp57 hypothesis, which this study's data strongly support.
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PMID:An explanation for the neutral effect of DR2 on IDDM susceptibility in central Italy. 162 63

MHC associations with IDDM in a Chinese population were studied to investigate genetic susceptibility to the disorder. The frequency of HLA-DR3 was significantly higher in the diabetic patients (19/49 [38.7%] vs. control subjects, 11/105 [10.5%], Pc less than 1.3 x 10(-3), RR = 5.3 [CI 2.3-12.1]), whereas DR4 was not (11/49 [22.4%] vs. 28/105 [26.7%], NS). The frequency of DR3/4 heterozygosity was higher in the diabetic patients (6/49 [12.2%] vs. control subjects, 0/105 [0%], P = 1.7 x 10(-3), RR = 31.5 [CI 3.8-263.6]). The frequency of DR3/9 heterozygosity also was higher in the diabetic patients (6/49 [12.2%] vs. control subjects, 2/105 [1.9%], P = 0.03, RR = 6.2 [CI 3.0-12.7]). No significant associations were noted between DQB1 alleles and IDDM. Among DR4-positive subjects, the frequency of DQB1 allele DQB1*0302 was higher in the diabetic patients (10/11 [90.0%] vs. control subjects, 12/24 [50%], Pc less than 0.05, RR = 7.0 [CI 1.3-38.0]), and the frequency of DQB1*0401 was significantly lower in the diabetic patients (2/11 [18.2%] vs. control subjects, 16/24 [66.7%], Pc = 0.04, RR = 0.1 [CI 0.02-0.46]). No DR4 subtype was associated significantly with IDDM. The frequency of DQA1*0501, a DQA1 allele, was higher in diabetic patients (22/41 [53.7%] vs. control subjects, 20/95 [21.1%], Pc less than 3 x 10(-3), RR = 4.3 [CI 2.0-9.3]). The frequency of DQA1*0301, which has been associated consistently with IDDM in other ethnic groups, was not significantly higher in the diabetic patients in this study (27/41 [65.9%] vs. control subjects, 53/95 [55.8%], NS).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Susceptibility to IDDM in a Chinese population. Role of HLA class II alleles. 162 65

In this study we report for the first time, the molecular analysis of HLA-DR and -DQ gene frequencies in a large cohort of well characterized type 1 (insulin-dependent) diabetes mellitus (IDDM) patients (n = 72), and ethnically matched controls (n = 59) collected in sub-Saharan Africa. High molecular mass DNA was prepared and analyzed in Southern blots with DRB1, DQA1, and DQB1 probes. By identifying DR and DQ allele-specific restriction fragment length polymorphisms (RFLPs), we have shown a strong positive association between IDDM and the Asp 57- DQB1 allele *0201 (DQw2). A rare DR4, DQw2 haplotype was also identified at high frequency in the IDDM cohort. We can now confirm that the association between Asp 57-DQB1 alleles and IDDM, previously reported in ethnically diverse cohorts collected in Western Europe, North America, and South Asia, is also present in an IDDM cohort collected in Africa.
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PMID:Analysis of HLA-DR and -DQ gene polymorphisms in Sudanese patients with type 1 (insulin-dependent) diabetes. 168 74

There are three common C2 protein alleles in caucasians, C2*C, C2*B, and C2*Q0, with allele frequencies of 0.96, 0.03, and 0.01, as well as Sst I RFLP variants of 2.75, 2.7, 2.65, 2.55, and 2.4 kb, with frequencies of 0.017, 0.533, 0.358, 0.017, and 0.075. Thus, C2*C is informatively split by the RFLP. Of 94 nonrandomly ascertained caucasian complotypes, 77 contained C2*C, four contained C2*Q0, and 13 had C2*B. None of the C2*C-containing complotypes carried the 2.75 kb Sst I fragment and all of the complotypes with C2*B or C2*Q0 carried it. All of the C2*Q0 alleles were associated with C4A*4, C4B*2 in the complotype S042 as previously reported. C2*B was usually (9/13) in the complotype SB42, occasionally (1/13 each) in SB45, SB41, SB(4,3)0, and SB31. Thus, the association of the C2 2.75-kb fragment was with C2*B and C2*Q0, not with C4A*4, C4B*2, or even C4A*4 alone. The complotype SC42 was associated with the 2.65-kb Sst I fragment in four of five instances and in a single example with the 2.7-kb fragment. C2*B and C2*Q0 possibly had a common evolutionary ancestor complotype which carried the 2.75-kb Sst I fragment, and BF*S, C4A*4, and C4B*2. C2*B (particularly as the haplotype HLA-Bw62, SB42, DR4) is associated with type 1 diabetes but C2*Q0 is protective.
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PMID:A restriction fragment of the C2 gene is a unique marker for C2 deficiency and the uncommon C2 allele C2*B (a marker for type 1 diabetes). 168 65

Eighty unrelated diabetic children, seventy healthy controls and hundred and ten affected and unaffected first-degree relatives of twenty multiplex families were investigated by restriction fragment length polymorphism analysis of HLA class II genes using five probe/enzyme systems: DRB and DQB/Taq I, DRB and DQB/EcoRI and DQB/BamHI according to standard procedures described in the 10th Histocompatibility Workshop protocol. Comparison between the unrelated diabetic patients and the controls confirmed the positive association of type 1 diabetes with DR3(w17)DQw2 Dw24 or Dw25 and DR4DQw8 and the negative association with DR2(w15)DQw6, DR4DQw7 and DR7DQw2 haplotypes. In multiplex families, similar allele associations were found and the distinction between haplotypes present in diabetic patients and those that segregated to healthy family members allowed to observe striking differences between the "affected" and "unaffected" haplotypes, particularly for the subtypes of DR3(w17) DQw2, DR4DQw3 and DR2DQw1 haplotypes. Heterozygous siblings who carried both DR3DQw2 and DR4DQw8 subtypes disclosed a highly increased risk and more than 80% of DR3/DR4 affected siblings received a paternal DR4DQw8 together with a maternal DR3DQw2. These observations indicate that several genetic aspects influence susceptibility to type 1 diabetes: 1) some particular HLA class II subsets; 2) the parental origin of the predisposing genes; 3) the synergistic effect of both haplotypes, in particular DR3DQw2 and DR4DQw8. These results may help to better specify susceptibility markers for risk prediction in siblings.
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PMID:DNA polymorphism analysis of HLA class II genes in unrelated children and in first-degree relatives with type I diabetes. 168 61

T cell defined epitopes on class II HLA molecules (epitopes distinguishable by T cells but not by antibodies) seem to be important determinants of IDDM susceptibility/resistance. Although HLA-DR4 is associated with IDDM in many populations, DR4-positive HLA haplotypes vary greatly (relative risk from greater than 10 to less than 1). This variation seems to depend on both the DQ allele and T cell defined subtypes of the DR4 allele. These IDDM associated alleles at the two loci (DQB1 and DRB1) are not correlated with each other in the healthy population, so they clearly are independent risk factors. HLA-DR2 has universally been associated with lack of IDDM, and seems to be protective. However, not all DR2 haplotypes protect, and the protection or lack of protection correlates with T cell defined subtypes of DR2. In this case, however, the DR2 subtypes do correlate with DQ alleles, so it is unclear which locus (loci) is (are) actually affecting the disease process. It may be significant that, for both DR2 and DR4, only the more protective subtypes have arginine at amino acid position 71. Other portions of the DR beta chain are clearly important, however. Although TCR alpha and beta seemed to be promising candidates for additional IDDM susceptibility genes, in fact the various TCR alpha and beta haplotypes are equal, or nearly equal, with regard to IDDM susceptibility. The importance of HLA alleles in IDDM susceptibility, and the lack of importance of TCR alpha and beta alleles, may be due to the different means by which the HLA and TCR molecules achieve antigen binding diversity: HLA molecules by multiple loci and allelic diversity, and TCR molecules by the tremendous diversity that can be generated from a single TCR allele during T cell maturation.
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PMID:T cell defined HLA epitopes and T cell receptor polymorphism in insulin dependent diabetes mellitus. 171 35

Insulin-dependent diabetes mellitus is common in Tunisia. Eighty-six pediatric cases managed at the diabetes clinic of a department of pediatrics in Tunis from 1979 through 1989 were studied. Relevant clinical and biological findings were abstracted from case-records. Admissions of patients with diabetes mellitus accounted for approximately 0.44% of admissions to the pediatric ward during the study period. Mean age of patients was 7 years. Sex ratio was 0.89. Polyuria with polydipsia and ketoacidosis were the two most common presenting manifestations. Mean blood glucose level at diagnosis was 22.44 mmol/l. Rate of consanguinity was 48%. HLA typing studies demonstrated a high prevalence of DR3 and DR4 alleles and especially of simultaneous expression of both these alleles. Several factors are incriminated in the development of childhood insulin-dependent diabetes mellitus.
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PMID:[An analytic study of cases of childhood diabetes in a pediatric department in Tunis]. 175 Jul 45


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