The effect of two frequent amino acid variants of the hepatocyte nuclear factor-1alpha gene on estimates of the pancreatic beta-cell function in Caucasian glucose-tolerant first-degree relatives of type 2 diabetic patients

J Clin Endocrinol Metab. 1998 Nov;83(11):3992-5. doi: 10.1210/jcem.83.11.5228.

Abstract

The objective of the present study was to investigate whether the frequent amino acid polymorphisms, Ile/Leu27 and Ser/Asn487, of the hepatocyte nuclear factor-1alpha gene were associated with alterations in glucose-induced serum C-peptide and serum insulin responses among glucose-tolerant first-degree relatives of type 2 diabetic patients. The study comprised 2 independent Danish cohorts. Among 74 unrelated type 2 diabetic relatives, 12 homozygous carriers of the Ile/Leu27 polymorphism had a 32% decrease in the 30-min serum C-peptide level (P = 0.01), as well as a 39% decrease in the 30-min serum insulin level (P = 0.02) during an oral glucose tolerance test. Ten homozygous carriers of the Ile/Leu27 variant did, however, not differ from wild-type carriers, with respect to the acute circulating insulin and serum C-peptide responses during an i.v. glucose tolerance test in the same study cohort. In a larger (more than 3-fold) study group of 230 glucose tolerant offspring of 62 type 2 diabetic probands, 33 homozygous carriers of the Ile/Leu27 variant did not differ, with respect to either serum insulin and serum C-peptide levels during an oral glucose tolerance test or acute serum insulin and serum C-peptide responses during an i.v. glucose tolerance test. We therefore consider the former positive finding as a statistical type I error. There were no differences in the above mentioned variables between carriers of the Ser/Asn487 polymorphism and wild-type carriers within any of the 2 study populations. Nor did carriers of combined genotypes, i.e. carriers of both the Ile/Leu27 and the Ser/Asn487 variants, show any associations with the examined variables. In conclusion, the Ile/Leu27 and Ser/ Asn487 polymorphisms of the hepatocyte nuclear factor-1alpha gene have apparently no major impact on the pancreatic beta-cell function, after an oral and i.v. glucose challenge, in Caucasian first-degree relatives of type 2 diabetic patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amino Acid Substitution
  • Asparagine
  • C-Peptide / metabolism
  • DNA-Binding Proteins*
  • Diabetes Mellitus, Type 2 / genetics*
  • European Continental Ancestry Group / genetics*
  • Female
  • Genetic Variation*
  • Glucose Tolerance Test
  • Hepatocyte Nuclear Factor 1
  • Hepatocyte Nuclear Factor 1-alpha
  • Hepatocyte Nuclear Factor 1-beta
  • Humans
  • Insulin / blood
  • Islets of Langerhans / physiology*
  • Isoleucine
  • Leucine
  • Male
  • Middle Aged
  • Nuclear Proteins / genetics*
  • Serine
  • Transcription Factors / genetics*

Substances

  • C-Peptide
  • DNA-Binding Proteins
  • HNF1A protein, human
  • HNF1B protein, human
  • Hepatocyte Nuclear Factor 1-alpha
  • Insulin
  • Nuclear Proteins
  • Transcription Factors
  • Isoleucine
  • Hepatocyte Nuclear Factor 1
  • Hepatocyte Nuclear Factor 1-beta
  • Serine
  • Asparagine
  • Leucine