title: HNF-1alpha G319S, a transactivation-deficient mutant, is associated with altered dynamics of diabetes onset in an Oji-Cree community.
abstract: The prevalence of type 2 diabetes mellitus in the Oji-Cree of northwestern Ontario is the third highest in the world. A private mutation, G319S, in HNF1A, which encodes hepatic nuclear factor-1alpha (HNF-1alpha), was associated with Oji-Cree type 2 diabetes and was found in approximately 40% of affected subjects. The G319S mutation reduced the in vitro ability of HNF-1alpha to activate transcription by approximately 50%, with no effect on DNA binding or protein stability. There was no evidence of a dominant negative effect of the mutant protein. 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. Disease onset was modeled satisfactorily by two-parameter sigmoidal functions for all diabetic subjects and all three HNF1A genotypes. Pairwise statistical comparisons showed significant between-genotype differences in t50 (all P < 0.00001), corresponding to the age at which half the subjects had become diabetic. Each dose of G319S accelerated median disease onset by approximately 7 years. Thus, the transactivation-deficient HNF1A G319S mutation affects the dynamics of disease onset. The demonstration of a functional consequence for HNF1A G319S provides a mechanistic basis for its strong association with Oji-Cree type 2 diabetes and its unparalleled specificity for diabetes prediction in these people, in whom diabetes presents a significant public health dilemma. The findings also show that HNF1A mutations can be associated with typical adult-onset insulin-resistant obesity-related diabetes in addition to maturity-onset diabetes of the young.
authors.affiliation: Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada R3E 0W3.
authors.forename: Barbara L
authors.initials: BL
authors.lastname: Triggs-Raine
authors.forename: Robert D
authors.initials: RD
authors.lastname: Kirkpatrick
authors.forename: Sherrie L
authors.initials: SL
authors.lastname: Kelly
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Norquay
authors.forename: Peter A
authors.initials: PA
authors.lastname: Cattini
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yamagata
authors.forename: Anthony J G
authors.initials: AJ
authors.lastname: Hanley
authors.forename: Bernard
authors.initials: B
authors.lastname: Zinman
authors.forename: Stewart B
authors.initials: SB
authors.lastname: Harris
authors.forename: P Hugh
authors.initials: PH
authors.lastname: Barrett
authors.forename: Robert A
authors.initials: RA
authors.lastname: Hegele
mesh_terms: D000328:Adult; D000368:Aged; D002170:Canada; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology / Q000235:genetics*; D006367:HeLa Cells; D051537:Hepatocyte Nuclear Factor 1; D051538:Hepatocyte Nuclear Factor 1-alpha; D051539:Hepatocyte Nuclear Factor 1-beta; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D009687:Nuclear Proteins; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; C496487:HNF1A protein, human; C496495:HNF1B protein, human; D051538:Hepatocyte Nuclear Factor 1-alpha; D009687:Nuclear Proteins; D014157:Transcription Factors; D051537:Hepatocyte Nuclear Factor 1; D051539:Hepatocyte Nuclear Factor 1-beta; D004247:DNA