Diabetes Care, Vol 23, Issue 6 775-778, Copyright © 2000 by American Diabetes Association
Clinical utility of HNF1A genotyping for diabetes in aboriginal Canadians
RA Hegele, H Cao, AJ Hanley, B Zinman, SB Harris and CM Anderson
John P. Robarts Research Institute, and Department of Medicine, University of Western Ontario, London, Canada. robert.hegele@rri.on.ca
OBJECTIVE: To determine the diagnostic performance characteristics of HNF1A
genotyping for diabetes and impaired glucose tolerance (IGT) in Canadian
Oji-Cree Indians. RESEARCH DESIGN AND METHODS: We studied all Oji-Cree
subjects > or = 50 years of age (96 subjects) who had participated in a
community-wide prevalence survey for type 2 diabetes. Subjects were
classified either as having "disease," which included type 2 diabetes and
IGT, or not. All subjects were genotyped for the HNF1A G319S mutation.
RESULTS: The prevalence of disease in this group was 65.7%, of whom 71.4%
had type 2 diabetes. For a carrier of HNF1A S319, the specificity,
sensitivity, and positive and negative predictive values were 97.0, 30.1,
95.0, and 42.1%, respectively. When the pretest disease prevalence was
accounted for, the probability of disease after a positive test was 97.2%,
and the probability of disease after a negative test was 42.2%. The values
were very similar for the subgroup of subjects with type 2 diabetes alone.
CONCLUSIONS: The HNF1A genotype appears to be the most specific genetic
test yet reported for the prediction of a common multifactorial disease by
applying present-day standards of clinical epidemiology in molecular
genetics. A positive test result had particular diagnostic value in the
Oji-Cree: a subject with HNF1A S319 was virtually certain of having
diabetes or IGT by 50 years of age. In contrast, a subject without HNF1A
S319 had a reduced risk compared with the age-specific prevalence but was
not totally risk-free. Because HNF1A S319 was not the only predisposing
factor for diabetes in the Oji-Cree, subjects without HNF1A S319 were still
at some risk for diabetes or IGT.