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

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.
 ...
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.
 ...
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.
 ...
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.
 ...
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.
 ...
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.
 ...
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.
 ...
PMID:A newly discovered role of transcription factors involved in pancreas development and the pathogenesis of diabetes mellitus. 946 79

A mild form of diabetes in young people was recognized in the pre-insulin era but was forgotten, probably because of Joslin's dictum that all young people with diabetes should have insulin as a safeguard against complications. After the introduction of sulphonylureas in the 1950s it was found, most notably by Fajans and Conn at the University of Michigan, that tolbutamide could improve or normalize carbohydrate tolerance in some young non-obese mildly diabetic patients. These experiments were not primarily of genetic interest because diabetes was regarded as homogeneous with young and old patients forming part of the same continuum. The question was whether treatment could prevent young subjects with mild diabetes progressing to a total loss of insulin reserve. By 1973, Fajans had shown that the carbohydrate intolerance of 45 patients diagnosed under age 25 had not progressed after up to 16 years on sulphonylureas. Nearly all (43 out of 45) these subjects had a first degree relative with diabetes. In 1974, under the title 'Mild familial diabetes with dominant inheritance' Tattersall described three families in which diabetes, although diagnosed in adolescence, could be treated with sulphonylureas over 40 years later and was dominantly inherited. Collaboration between Fajans and Tattersall established that 'chemical' diabetes in Michigan was also predominantly inherited and distinct from classical 'juvenile-onset' diabetes. In Paris in 1973 Lestradet also described a non-insulin-dependent form of childhood diabetes and later established that it was dominantly inherited. In 1974, Tattersall and Fajans coined the acronym MODY which was defined as 'fasting hyperglycaemia diagnosed under age 25 which could be treated without insulin for more than two years'.
 ...
PMID:Maturity-onset diabetes of the young: a clinical history. 947 58

The aim of this study is to understand better the genetic causes of type II diabetes and the phenotypic consequences of the genetic changes. We first investigated the relative prevalence of the different forms of diabetes in young adults and their clinical features. 51 non-obese patients were identified in whom diabetes had been diagnosed before age 40; cases of typical insulin-dependent type I diabetes were excluded. A search for mutations of the glucokinase and HNF-1 alpha genes and for mitochondrial DNA was made, anti-islet and anti-GAD antibodies were determined and HLA class II genotyping was performed. Patients were subdivided on clinical grounds into a MODY (maturity onset diabetes of the young) group (n = 19) and a non-MODY group (n = 32). MODY is a form of diabetes which has an autosomal dominant inheritance for which 3 genes have already been implicated (MODY1, HNF-4 gene; MODY2, glucokinase gene, and MODY3, HNF-1 alpha gene). In the MODY group we identified 3 patients with MODY2, 1 with MODY3, 1 with the 3243 mitochondrial mutation and a further patient with autoimmune diabetes. In the non-MODY group we found 5 patients with autoimmune diabetes and 1 with MODY2. No clinical parameter was helpful in classifying patients in one of these subclasses of diabetes; however, glucagon stimulated C-peptide was useful in discriminating between MODY2 patients and the others. Young and lean non-insulin-dependent diabetic patients thus constitute a very heterogeneous group, though presenting similar clinical features. In the second study we analyzed hepatic glucose metabolism in patients with a mutation of the glucokinase gene expressed in both liver and islet beta cells. We found that endogenous glucose production is inadequately inhibited by hyperglycemia, a fact which contributes to the pathogenesis of hyperglycemia in these patients.
 ...
PMID:[Swiss journey through the clinical and genetic characteristics of diabetes in young patients]. 952 22

The related homeodomain-containing transcription factors HNF1 (HNF1 alpha) and vHNF1 (HNF1 beta) recognise common target DNA sequences in the regulatory regions of many genes and are expressed in several parenchymal cell types, predominantly in liver, kidney, intestine and pancreas. HNF1-null mutant mice, with a wild-type vHNF1 gene, develop normally, but die within a few weeks of birth with severe liver and kidney failure. Humans with a mutation in the HNF1 alpha gene develop non-insulin dependent diabetes on maturity (MODY 3). To determine distinctive roles for each of these proteins we produced a set of polyclonal sera and monoclonal antibodies, directed against different parts of the rat HNF1 and vHNF1 proteins. These antibodies reveal that HNF1 is present in vivo as a heterogeneous mixture of 92-98 kDa molecular mass polypeptides, a mass higher than that expected from its amino acid sequence. vHNF1 is present in the form of two isoforms of roughly the expected molecular masses, 65 and 68 kDa. In addition, some antibodies prepared against bacterially-produced HNF1 recognise vHNF1 but not HNF1, in liver and kidney extracts. Hence, we present the first evidence for differential post-translational modification of HNF1 and vHNF1 proteins.
 ...
PMID:A set of polyclonal and monoclonal antibodies reveals major differences in post-translational modification of the rat HNF1 and vHNF1 homeoproteins. 952 12


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>