High frequency of mutations in the HNF-1alpha gene in non-obese patients with diabetes of youth in Japanese and identification of a case of digenic inheritance

Diabetologia. 2002 Dec;45(12):1709-12. doi: 10.1007/s00125-002-0978-3. Epub 2002 Nov 16.

Abstract

Aims/hypothesis: There is an emerging epidemic of Type II (non-insulin-dependent) diabetes mellitus of youth in Japan and in many other developed countries. The aim of this study was to determine the prevalence of mutations in the hepatocyte nuclear factor (HNF)-1alpha gene (TCF1) in a large group of Japanese patients with early-onset non-Type I (insulin-dependent) diabetes mellitus. Since approximately 20% of Caucasian patients with HNF-1alpha mutations have been shown to be obese or overweight, we also examined the association of genetic variations in TCF1 with body weight in Japanese subjects.

Methods: We examined 203 patients with non-Type 1 diabetes who had been diagnosed before they reached 15 years of age. Ten exons and flanking introns of TCF1 of these patients were directly sequenced for mutations.

Results: We found 14 different mutations in 18 patients (8.9%), including one that was found to be de novo. The patients with the mutations had lower BMI (20.1+/-3.0 kg/m(2)) at diagnosis than the patients without them (24.5+/-6.0 kg/m(2)) (p=0.0024). All of the patients with the mutations, except for one, Y120, had normal body weight (BMI<25 kg/m(2)); the frequency of HNF-1alpha mutations in the non-obese patients of this study was 17% (17/101). Patient Y120, who had atypical symptoms of mild obesity and insulin resistance at diagnosis, was found to have inherited an additional mutation in an obesity-related gene.

Conclusion/interpretation: A considerable number of non-obese Japanese patients with non-Type 1 diabetes of youth have HNF-1alpha-deficient diabetes. Lack of obesity could well be a characteristic feature of this form of diabetes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asian Continental Ancestry Group / genetics*
  • Body Mass Index
  • Body Weight
  • Child
  • DNA-Binding Proteins*
  • Diabetes Mellitus, Type 2 / complications
  • Diabetes Mellitus, Type 2 / genetics*
  • Diabetes Mellitus, Type 2 / pathology
  • Female
  • Gene Frequency*
  • Hepatocyte Nuclear Factor 1
  • Hepatocyte Nuclear Factor 1-alpha
  • Hepatocyte Nuclear Factor 1-beta
  • Humans
  • Insulin Resistance / genetics
  • Japan
  • Male
  • Mutation*
  • Nuclear Proteins*
  • Obesity / complications
  • Obesity / genetics
  • Transcription Factors / genetics*

Substances

  • DNA-Binding Proteins
  • HNF1A protein, human
  • HNF1B protein, human
  • Hepatocyte Nuclear Factor 1-alpha
  • Nuclear Proteins
  • Transcription Factors
  • Hepatocyte Nuclear Factor 1
  • Hepatocyte Nuclear Factor 1-beta