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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

MODY is a sub-type of NIDDM. It is characterized by an early age of onset and autosomal dominant mode of inheritance. These features, and the availability of large multigenerational pedigrees, make MODY useful for genetic studies of diabetes. In the large 5-generational RW pedigree, MODY is tightly linked to genetic markers on chromosome 20q. Affected subjects in this family show abnormalities of carbohydrate metabolism, varying from impaired glucose tolerance (IGT) to severe diabetes. Approximately 30% of diabetic subjects become insulin-requiring, and vascular complications occur. MODY is also linked to the glucokinase gene on chromosome 7p and many different mutations associated with MODY have been identified in this gene. MODY, due to mutations in the glucokinase gene, is a relatively mild form of diabetes with mild fasting hyperglycaemia and IGT in the majority. Clinical investigative studies indicate that the genetic or primary defect in MODY is characterized by deranged and deficient insulin secretion and not by insulin resistance. There are quantitative and qualitative differences in insulin secretory defects which differentiate subjects with MODY due to mutation in the gene on chromosome 20q from those with glucokinase mutations. These differences correlate with the severity of diabetes between these two genetic forms of MODY.
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PMID:Maturity onset diabetes of the young (MODY). 889 90

Some patients with Type 2 (non-insulin-dependent) diabetes mellitus possess a mitochondrial mutation in the tRNA(Leu(UUR)) gene at position 3243 bp. These subjects show a maternal mode of inheritance and often have hearing defects. In French and Japanese populations, this mutation may be present in 1-3% of subjects with a family history of diabetes. We assessed the prevalence of this mutation in newly diagnosed diabetic subjects in the UK white Caucasian population. The 3243 bp mutation was not detected in 500 randomly selected Type 2 diabetic subjects, 50 gestational diabetic subjects, and members of a MODY pedigree. Two of 748 (0.27%) Type 2 diabetic subjects with a family history of diabetes were found to possess the mutation. These subjects had an early age of diagnosis (M 38 years; F 36 years) and were non-obese. The male patient showed evidence of markedly impaired beta-cell function and deafness, while the female was not deaf, had approximately 50% of normal pancreatic function and responded well to diet. The mutation in the tRNA(Leu(UUR)) gene probably occurs in only approximately 0.1-0.2% of white Caucasian Type 2 diabetic patients in the UK.
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PMID:UKPDS 21: low prevalence of the mitochondrial transfer RNA gene (tRNA(Leu(UUR))) mutation at position 3243bp in UK Caucasian type 2 diabetic patients. 901 52

We have recently shown that mutations in the gene encoding the transcription factor hepatocyte nuclear factor (HNF)-1alpha are the cause of one form of maturity-onset diabetes of the young (MODY3). Here, we report the exon-intron organization and partial sequence of the human HNF-1alpha gene. In addition, we have screened the ten exons and flanking introns of this gene for mutations in a group of 25 unrelated white subjects from Germany who presented with NIDDM before 35 years of age and had a first-degree relative with NIDDM. Mutations were identified in nine of these individuals, suggesting that mutations in the HNF-1alpha gene are a common cause of diabetes in German subjects with early-onset NIDDM and a family history of diabetes. Thus, screening for mutations in this gene may be indicated in subjects with early-onset NIDDM. Interestingly, three of the nine mutations occurred at the same site in exon 4 with insertion of a C in a polyC tract, centered around codon 290 (designated Pro291fsinsC), thereby resulting in a frameshift during translation and premature termination. Analyses of linked DNA polymorphisms in the HNF-1alpha gene indicated that the Pro291fsinsC mutation was present on a different haplotype in each subject, implying that the polyC tract represents a mutational hot spot. We have also identified the mutation in the HNF-1alpha gene in the Jutland pedigree, one of the original MODY pedigrees reported in the literature, as being a T-->G substitution in codon 241, resulting in the replacement of a conserved Cys by Gly (C241G). The information on the sequence of the HNF-1alpha gene and its promoter region will facilitate the search for mutations in other subjects and studies of the role of the gene in determining normal beta-cell functions.
Diabetes 1997 Mar
PMID:Mutations in the hepatocyte nuclear factor-1alpha gene in MODY and early-onset NIDDM: evidence for a mutational hotspot in exon 4. 903 14

The aim of our study was to investigate the relative prevalence of the different forms of diabetes in young adults and their respective clinical characteristics. Included were 51 nonobese patients (BMI < 27 kg/m2) with diabetes diagnosed before age 40, excluding typical IDDM. Each patient was subjected to screening for glucokinase gene (MODY2) and mitochondrial DNA (at nucleotide 3243) mutations, to HLA class II genotyping, and screening for the presence of islet cell antibodies (ICAs) and anti-GAD antibodies. Informative families were analyzed for linkage of diabetes to chromosome 12q (MODY3). Based on clinical criteria, patients were subdivided into MODY (n = 19) and non-MODY (n = 32). In the MODY group, we identified three patients with MODY2, one with the 3243 mitochondrial mutation, and another with autoimmune diabetes. One of the five MODY families available for linkage study was shown to have MODY3. In the non-MODY group, we found five patients with autoimmune diabetes and one with MODY2. No clinical parameter was helpful to classify patients in one of these subclasses of diabetes; however, the glucagon-stimulated C-peptide was useful to discriminate between MODY2 patients and the others. In conclusion, young and lean non-insulin-dependent diabetic patients constitute a very heterogeneous group, although they present similar clinical characteristics. The clinical distinction of MODY and non-MODY patients allows correct classification in, at most, 75% of the patients and thus is not sufficient to predict clinical course. However, immunological and genetic parameters allowed us to classify only 25% of the patients in specific diagnostic classes.
Diabetes 1997 Apr
PMID:Diagnostic heterogeneity of diabetes in lean young adults: classification based on immunological and genetic parameters. 907 2

One form of maturity-onset diabetes of the young (MODY3) results from mutations in the hepatocyte nuclear factor (HNF)-1alpha gene, located on chromosome 12q24.2. The primary objective of the present study was to search for genetic variation in the HNF-1alpha gene in nine nonrelated Danish Caucasian subjects with MODY. Direct sequencing of the coding region and intron-exon boundaries of the HNF-1alpha gene revealed 2 novel and 1 previously reported missense mutations and 2 novel frameshift mutations in five of nine MODY subjects. These five mutations were found in neither 84 NIDDM patients nor 84 control subjects. One glucose-tolerant lean male with a P447L missense mutation, which in his relatives caused MODY, underwent an oral glucose tolerance test (OGTT), a tolbutamide modified frequently sampled intravenous glucose tolerance test, and a glucagon test to examine for a possible early beta-cell abnormality. He had a low insulin secretion rate during an OGTT, but a twofold increase in pancreatic beta-cell response after intravenous glucose and a 2.5- to 4-fold increase in beta-cell response after either intravenous tolbutamide or intravenous glucagon loads. In conclusion, 1) mutations in the HNF-1alpha gene are common in Danish Caucasian MODY patients, and 2) early stages in the pathogenesis of MODY3 caused by the P447L mutation may be characterized by a hyperexcitability of beta-cells to intravenous secretagogues.
Diabetes 1997 Apr
PMID:Novel MODY3 mutations in the hepatocyte nuclear factor-1alpha gene: evidence for a hyperexcitability of pancreatic beta-cells to intravenous secretagogues in a glucose-tolerant carrier of a P447L mutation. 907 19

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.
Diabetes 1997 Aug
PMID:Pancreatic islet expression studies and polymorphic DNA markers in the genes encoding hepatocyte nuclear factor-3alpha, -3beta, -3gamma, -4gamma, and -6. 923 64

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.
Diabetes 1997 Oct
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.
Diabetes 1997 Oct
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

The prevalence of diabetes mellitus is increasing worldwide, averaging 5% to 15% in various population groups. Diabetes predisposes to premature morbidity and death. The underlying metabolic cause of diabetes is a failure of the beta-cells of the pancreas to provide insulin in amounts sufficient to meet the body's needs, leading to hyperglycemia. Juvenile (type 1) diabetes results from immune destruction of the beta-cells. Adult onset (type 2) diabetes, which accounts for 90% of all forms of diabetes, is a complex polygenic disease manifested in a dysregulation of insulin secretion. Environmental influences and complex genetic traits contribute to the pathogenesis of both types of diabetes. However, a subpopulation of type 2 diabetes is monogenic and due to inactivating mutations in genes that are critical for normal beta-cell function. Heterozygous carriers of the mutant genes develop early-onset diabetes known as MODY (mature onset diabetes of the young). Notably, three MODY genes encode transcription factors implicated in the regulation of insulin gene transcription: hepatocyte nuclear factors 1 alpha and 4 alpha, and islet duodenum homeobox-1 (IDX-1, also known as IPF-1). The fourth gene encodes glucokinase, the rate-limiting enzyme required for glucose metabolism in beta-cells. Further, an individual born without a pancreas (agenesis) is homozygous for an inactivating mutation of the IDX-1 gene, recapitulating the phenotype of the IDX-1 knockout mouse and demonstrating that expression of IDX-1 is critical for pancreas development. Recently, mouse knockouts of the transcription factors Pax4, Pax6, beta 2/neuroD, and Isl-1 result in severe anomalies in the development of the endocrine pancreas. Gene mutations for these factors are possible candidates for additional MODY genes.
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PMID:A newly discovered role of transcription factors involved in pancreas development and the pathogenesis of diabetes mellitus. 946 79


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