Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two genes that have potentially important regulatory roles in insulin secretion are both located on chromosome 2q24.1. G-protein-coupled muscarinic potassium channel (GIRK1) is an inwardly rectifying K+ channel that helps to maintain the resting potential and excitability of cells. Mitochondrial FAD-linked glycerophosphate dehydrogenase (m-GDH) catalyzes a rate-limiting step of the glycerol phosphate shuttle in pancreatic islets. Reduced m-GDH activity has been demonstrated in islets isolated from diabetic subjects compared with islets from nondiabetic control subjects and from the diabetic GK rat. To study the relationship between these candidate genes and NIDDM, we have examined a simple tandem-repeat polymorphism (STRP) close to both the KCN J3 (GIRK1) locus and the m-GDH locus. In a linkage study of three maturity-onset diabetes of the young (MODY) pedigrees, not linked to MODY1, MODY2, or MODY3, a cumulative score of - 9.6 at a recombination fraction of theta = 0 excluded linkage. In a population-association study, no linkage disequilibrium for the STRP was found between 190 unselected NIDDM patients and 60 geographically and age-matched white nondiabetic subjects (chi2 = 1.51 on 3 df, P = 0.68). Thus, mutations involving the genes for GIRK1 or FAD-glycerophosphate dehydrogenase are unlikely to cause MODY, and a common mutation in either gene is unlikely to contribute to NIDDM in whites. These data do not exclude mutations in some families or other ethnic groups.
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PMID:Mitochondrial FAD-glycerophosphate dehydrogenase and G-protein-coupled inwardly rectifying K+ channel: No evidence for linkage in maturity-onset diabetes of the young or NIDDM. 862 Oct 16

The disease maturity-onset diabetes of the young (MODY) is a genetically heterogeneous monogenic form of non-insulin-dependent (type 2) diabetes mellitus (NIDDM), characterized by early onset, usually before 25 years of age and often in adolescence or childhood, and by autosomal dominant inheritance. It has been estimated that 2-5% of patients with NIDDM may have this form of diabetes mellitus. Clinical studies have shown that prediabetic MODY subjects have normal insulin sensitivity but suffer from a defect in glucose-stimulated insulin secretion, suggesting that pancreatic beta-cell dysfunction rather than insulin resistance is the primary defect in this disorder. Linkage studies have localized the genes that are mutated in MODY on human chromosomes 20 (MODY1), 7 (MODY2) and 12 (MODY3), with MODY2 and MODY3 being allelic with the genes encoding glucokinase, a key regulator of insulin secretion, and hepatocyte nuclear factor-1alpha (HNF-1alpha), a transcription factor involved in tissue-specific regulation of liver genes but also expressed in pancreatic islets, insulinoma cells and other tissues. Here we show that MODY1 is the gene encoding HNF-4alpha (gene symbol, TCF14), a member of the steroid/thyroid hormone receptor superfamily and an upstream regulator of HNF-1alpha expression.
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PMID:Mutations in the hepatocyte nuclear factor-4alpha gene in maturity-onset diabetes of the young (MODY1) 894 61

Diabetes mellitus comprises a heterogeneous group of diseases which have chronic hyperglycaemia in common as well as the resulting microvascular, macrovascular and neurological complications of this condition. Familial studies have provided strong evidence for the existence of genetic determinants in the different types of diabetes. In particular, monozygotic twin studies have indicated a higher rate of concordance in non-insulin-dependent (NIDDM) than in insulin-dependent diabetes mellitus (IDDM). In IDDM, 8 susceptibility loci have been identified, notably the HLA complex and insulin promotor gene. Rigorous family studies have identified monogenic subtypes representing 10-15% of all NIDDM: MODY2 related to glucokinase gene mutations, MODY1 and MODY3 secondary to mutation of hepatic nuclear factors, and diabetes resulting from deletion or mutation of mitochondrial DNA. Most NIDDM result from polygenic heredity, and susceptibility genes conducive to increased receptivity to deleterious environmental influences are now under investigation, such as beta 3 adrenergic receptor, FABP2 and OB. Precise analysis of phenotypes in the remaining families or systematic screening of the genome could allow the genes of each subtype to be identified. Finally, susceptibility genes for the increased severity and frequency of vascular complications have been identified, such as angiotensin converting enzyme, aldose reductase and aldehyde dehydrogenase genes. This progress has been facilitated by developments in molecular biology.
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PMID:Diabetes: from phenotypes to genotypes. 910 79

To test the hypothesis that a gene (or genes) in the "MODY1 region" of the long arm of chromosome 20 contributes to the development of NIDDM, we conducted linkage studies in 29 extended Caucasian families in which many members were affected with NIDDM. A total of 498 individuals, including 159 NIDDM patients with an average age at diagnosis of 47 years, were genotyped for eight highly polymorphic microsatellite markers spanning a 31-cM region on chromosome 20q12-13.1. Using affected sib-pair analysis, we obtained evidence suggesting linkage between NIDDM and markers D20S119, D20S178, and D20S197 (allele sharing identical-by-descent [IBD], 0.56 for all three; P = 0.005, P = 0.009, and P = 0.004, respectively). Multipoint nonparametric linkage (NPL) analysis also showed evidence for linkage of NIDDM with the same three markers. The evidence for linkage was much stronger (allele sharing IBD by affected sibpairs, 0.64 [P < 0.0001]; maximum NPL score, 3.3 [P = 0.009]) in the 14 families whose average age at diagnosis of NIDDM was above the median (47 years) for all families. In these 14 families, one particular allele of the microsatellite D20S197 was transmitted from heterozygous parents to NIDDM offspring more frequently than expected (P < 0.01). This indicates that the marker allele and the disease allele are in linkage disequilibrium, implying that they are in close proximity. Consequently, the recently identified MODY1 gene (hepatocyte nuclear factor 4) is an unlikely candidate gene for NIDDM in our families, since it is located about 8 cM centromeric of D20S197. In conclusion, we have identified a new region on chromosome 20q that contains one or more NIDDM genes distinct from the recently identified MODY1 gene.
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PMID:New susceptibility locus for NIDDM is localized to human chromosome 20q. 913 58

The potential contribution of maturity-onset diabetes of the young (MODY) genes to NIDDM susceptibility in African-American and Caucasian NIDDM-affected sibling pairs with a history of adult-onset diabetic nephropathy has been evaluated. Evidence for linkage to NIDDM was found with polymorphic loci that map to the long arms of human chromosomes 20 and 12 in regions containing the MODY1 and MODY3 genes. Nonparametric analysis of chromosome 20 inheritance data collected with the MODY1-linked marker D20S197 provides evidence for linkage to NIDDM with a P value of 0.005 in Caucasian sib pairs using affected sibpair (ASP) analyses. Non-parametric analysis of chromosome 12 inheritance data collected with the MODY3-linked markers D12S349 and D12S86 provides evidence for linkage to NIDDM with P values of 0.04 and 0.006, respectively, in Caucasian sib pairs using similar analyses. No evidence for linkage of MODY1 and MODY3 markers to NIDDM in African-American sib pairs was observed. In addition, no evidence for linkage to MODY2 (glucokinase-associated MODY) was observed with either study population. Results of multipoint maximum logarithm of odds (LOD) score analysis were consistent with the ASP results. A maximum LOD score of 1.48 was calculated for linkage to MODY1-linked loci and 1.45 to MODY3-linked loci in Caucasian sib pairs. Tabulation of allele sharing in affected sib pairs with D20S197 and D12S349 suggests that affected sibling pairs may inherit susceptibility genes simultaneously from chromosome 20 and chromosome 12. The results suggest that genes contributing to NIDDM in the general Caucasian population are located in the regions containing the MODY1 and MODY3 genes.
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PMID:Linkage of genetic markers on human chromosomes 20 and 12 to NIDDM in Caucasian sib pairs with a history of diabetic nephropathy. 913 59

The genes encoding the functionally related hepatocyte nuclear factors HNF-1alpha and HNF-4alpha play a critical role in normal pancreatic beta-cell function. Mutations in these liver-enriched transcription factors result in two forms of early-onset type 2 diabetes (maturity-onset diabetes of the young [MODY]), MODY3 and MODY1, which are characterized by impaired glucose-stimulated insulin secretion, early disease onset, and autosomal dominant inheritance. The transcriptional hierarchy of HNFs suggests that other proteins of the regulatory cascade might be responsible for other forms of MODY and/or late-onset type 2 diabetes. In this study, we show that HNF-3alpha, -3beta, -3gamma, -4gamma, and -6 are expressed in pancreatic beta-cells. We report the identification and characterization of simple tandem repeat DNA polymorphisms in the genes encoding HNF-3alpha, -3beta, -3gamma, -4gamma, and -6 and the mapping of HNF-6 to chromosome bands 15q21.1-21.2 by fluorescence in situ hybridization. These markers will be useful to study the role of genetic variation in these genes in the pathogenesis of type 2 diabetes.
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PMID:Pancreatic islet expression studies and polymorphic DNA markers in the genes encoding hepatocyte nuclear factor-3alpha, -3beta, -3gamma, -4gamma, and -6. 923 64

Maturity-onset diabetes of the young (MODY) is a monogenic subgroup of non-insulin dependent diabetes mellitus (NIDDM) characterised bylan early age of onset (< 25 years) and an autosomal dominant mode of inheritance. MODY is genetically heterogeneous with three different genes identified to date; hepatocyte nuclear factor 4 alpha (HNF-4 alpha) [MODY1], glucokinase [MODY2] and hepatocyte nuclear factor 1 alpha (HNF-1 alpha) [MODY3]. A nonsense mutation in the HNF-4 alpha gene has recently been shown to cause MODY in a single large North American pedigree (RW). We screened a large UK Caucasian MODY family which showed weak evidence of linkage to the MODY1 locus on chromosome 20q (lod score for ADA 0.68 at theta = 0) for mutations in the coding region of the HNF-4 alpha gene by direct sequencing. A missense mutation resulting in the substitution of glutamine for glutamic acid was identified in exon 7 (E276Q). The mutation was present in all of the diabetic members of the pedigree plus two unaffected subjects and was not detected in 75 normal control subjects or 95 UK Caucasian subjects with late-onset NIDDM. This is the first missense mutation to be described in the HNF-4 alpha gene.
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PMID:A missense mutation in the hepatocyte nuclear factor 4 alpha gene in a UK pedigree with maturity-onset diabetes of the young. 924 9

Recent studies have shown that mutations in the transcription factor hepatocyte nuclear factor (HNF)-1 alpha are the cause of one form of maturity-onset diabetes of the young (MODY3). These studies have identified mutations in the mRNA and protein coding regions of this gene that result in the synthesis of an abnormal mRNA or protein. Here, we report an Italian family in which an A-->C substitution at nucleotide-58 of the promoter region of the HNF-1 alpha gene cosegregates with MODY. This mutation is located in a highly conserved region of the promoter and disrupts the binding site for the transcription factor HNF-4 alpha, mutations in the gene encoding HNF-4 alpha being another cause of MODY (MODY1). This result demonstrates that decreased levels of HNF-1 alpha per se can cause MODY. Moreover, it indicates that both the promoter and coding regions of the HNF-1 alpha gene should be screened for mutations in subjects thought to have MODY because of mutations in this gene.
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PMID:Maturity-onset diabetes of the young due to a mutation in the hepatocyte nuclear factor-4 alpha binding site in the promoter of the hepatocyte nuclear factor-1 alpha gene. 931 64

Hepatocyte nuclear factor-4 alpha (HNF-4 alpha) is a member of the nuclear receptor superfamily, a class of ligand-activated transcription factors. A nonsense mutation in the gene encoding this transcription factor was recently found in a white family with one form of maturity-onset diabetes of the young, MODY1. Here, we report the exon-intron organization and partial sequence of the human HNF-4 alpha gene. In addition, we have screened the 12 exons, flanking introns and minimal promoter region for mutations in a group of 57 unrelated Japanese subjects with early-onset NIDDM/MODY of unknown cause. Eight nucleotide substitutions were noted, of which one resulted in the mutation of a conserved arginine residue, Arg127 (CGG)-->Trp (TGG) (designated R127W), located in the T-box, a region of the protein that may play a role in HNF-4 alpha dimerization and DNA binding. This mutation was not found in 214 unrelated nondiabetic subjects (53 Japanese, 53 Chinese, 51 white, and 57 African-American). The R127W mutation was only present in three of five diabetic members in this family, indicating that it is not the only cause of diabetes in this family. The remaining seven nucleotide substitutions were located in the proximal promoter region and introns. They are not predicted to affect the transcription of the gene or mRNA processing and represent polymorphisms and rare variants. The results suggest that mutations in the HNF-4 alpha gene may cause early-onset NIDDM/MODY in Japanese but they are less common than mutations in the HNF-1 alpha/MODY3 gene. The information on the sequence of the HNF-4 alpha gene and its promoter region will facilitate the search for mutations in other populations and studies of the role of this gene in determining normal pancreatic beta-cell function.
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PMID:Organization and partial sequence of the hepatocyte nuclear factor-4 alpha/MODY1 gene and identification of a missense mutation, R127W, in a Japanese family with MODY. 931 65

Non-insulin-dependent diabetes mellitus (NIDDM) is the most common form of diabetes, affecting 5% of the general population. Genetic factors play an important role in the development of the disease. While in other populations NIDDM is usually diagnosed after the fifth decade of life, in Mexico a large proportion of patients develop the disease at an early age (between the third and the fourth decade). In Caucasian population, mutations in the glucokinase gene, the TCF1, and TCF14 genes, have been identified in a subgroup of early-onset NIDDM patients denominated MODY (maturity-onset diabetes of the young), which show an autosomal dominant pattern of inheritance. As a first step in the molecular characterization of Mexican families displaying early-onset NIDDM we searched for mutations in the glucokinase gene through SSCP analysis and/or direct sequencing in 26 individuals from 22 independent families, where at least four can be classified as MODY. No mutations were detected in the exons or the intron-exon boundaries of the gene in any of the screened individuals. The phenotype and clinical profile of some of the studied patients is compatible with that of patients carrying mutations in the TCF1 or TCF14 genes, while others may carry mutations in different loci. Through computer simulation analysis we identified at least four informative families which will be used for further linkage studies.
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PMID:Analysis of the glucokinase gene in Mexican families displaying early-onset non-insulin-dependent diabetes mellitus including MODY families. 937 18


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