The maturity-onset diabetes of the young (MODY), an autosomal dominant form of non-insulin dependent diabetes mellitus (NIDDM), is caused by mutations in the glucokinase (GK, MODY 2) and in the hepatocyte nuclear factor 1a (MODY 3) and 4a (MODY 1) genes.
The probable etiologic heterogeneity of type 2 diabetes in the Oji-Cree created a situation in which association analysis was much more sensitive to detect a relationship between HNF1A S319 and diabetes than was linkage analysis.
When taken together with the previously reported association of diabetes with HNF1A in both men and women, the gender-specific association with PPARG A12 confirms that type 2 diabetes is etiologically complex in the Oji-Cree and that at least two genes are involved in determining susceptibility to the disease in these people.
The identification of an HNF-1 alpha gene mutation in a patient with type 2 diabetes confirms the diagnosis of MODY and has important implications for clinical management.
To evaluate insulin sensitivity and insulin secretion in prediabetic and diabetic subjects with mutations in MODY1 (HNF-4 alpha) and MODY3 (HNF-1 alpha) genes, in subjects with GAD antibodies, latent autoimmune diabetes in adults and in subjects with the common form of Type II (non-insulin-dependent) diabetes mellitus.
We therefore assessed the counterregulatory responses to hypoglycemia in six patients with HNF-1alpha mutations (MODY3), five patients with non-insulin-dependent diabetes mellitus (NIDDM) and in nine healthy controls.
The P239Q variant was identified in two families with early-onset diabetes including one with MODY3 (R272C of HNF1alpha) and in three families with late-onset Type II diabetes.
Mutations in the hepatic nuclear factor-1 alpha and glucokinase are associated with Type II diabetes in 14 % and 7 % of Italian families, respectively.
The impact of the G319S mutation at the population level was assessed by classifying subjects with type 2 diabetes according to HNF1A genotype and plotting the cumulative age of onset of diabetes.
Evidence from a large U.K. family collection that genes influencing age of onset of type 2 diabetes map to chromosome 12p and to the MODY3/NIDDM2 locus on 12q24.
Polymorphisms of these genes (Ala45Thr [NEUROD1], Ser199Phe [NEUROG3], and Ala98Val [TCF1]) have been postulated to influence the development of type 2 diabetes.
The aim of this study was to investigate whether single nucleotide polymorphisms (SNPs) in the genes regulating insulin secretion (SLC2A2 [encoding GLUT2], GCK, TCF1 [encoding HNF-1alpha], HNF4A, GIP, and GLP1R) are associated with the conversion from impaired glucose tolerance (IGT) to type 2 diabetes in participants of the Finnish Diabetes Prevention Study.
A prevalent amino acid polymorphism at codon 98 (Ala98Val) of the hepatocyte nuclear factor-1alpha is associated with maturity-onset diabetes of the young and younger age at onset of type 2 diabetes in Asian Indians.
The risk of Type 2 diabetes was similar (approximately five-fold increased) for subjects with either the presence of the modified metabolic syndrome or the private HNF1AG319S mutation.
MODY is both clinically and genetically heterogeneous, with six different genes identified to date; glucokinase (GCK), hepatocyte nuclear factor-1 alpha (HNF1A, or TCF1), hepatocyte nuclear factor-4 alpha (HNF4A), insulin promoter factor-1 (IPF1 or PDX1), hepatocyte nuclear factor-1 beta (HNF1B or TCF2), and neurogenic differentiation 1 (NEUROD1).
We combined these results with our previous studies on HNF4alpha and TCF1 and explicitly tested for gene-gene interactions among these variants and with several known type 2 diabetes susceptibility loci, and we found no genetic interactions between these six genes.