-6A promoter variant of angiotensinogen and blood pressure variation in Canadian Oji-Cree

J Hum Genet. 1998;43(1):37-41. doi: 10.1007/s100380050034.

Abstract

We previously reported significant associations between variation in the AGT gene at codon 235 and both systolic pressure and hypertension in Canadian Oji-Cree. Recently, Inoue et al suggested that the AGT T235 variant was not causative, but was rather in linkage disequilibrium with a variant in the AGT promoter, namely -6A, that was associated with increased in vitro expression of angiotensinogen and was thus a strong candidate to be the functional basis of the previously observed associations. We genotyped 518 adult Oji-Cree for the AGT promoter polymorphism and tested for its association with blood pressure and hypertension. We found that the frequency of the -6A variant was 0.85 in the Oji-Cree, which is much higher than the frequency observed in other human samples. We also found strong linkage disequilibrium between the AGT -6A and T235 variants. However, genetic variation of the AGT promoter was only marginally associated with variation in systolic pressure, with a trend to significantly higher systolic pressure seen in AGT -6A/A homozygotes than in subjects with other genotypes. In addition, genetic variation of the AGT promoter tended to be associated with a diagnosis of hypertension. Despite the very high prevalence of -6A, our native sample was essentially normotensive. Our findings are consistent with a marginally deleterious effect of the AGT -6A allele on blood pressure, but linkage disequilibrium with another causative variant cannot be ruled out in this sample of aboriginal Canadians.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Angiotensinogen / genetics*
  • Base Sequence
  • Blood Pressure / genetics*
  • Canada
  • DNA Primers / genetics
  • Female
  • Gene Frequency
  • Genetic Variation
  • Humans
  • Hypertension / genetics
  • Indians, North American / genetics*
  • Linkage Disequilibrium
  • Male
  • Middle Aged
  • Promoter Regions, Genetic

Substances

  • DNA Primers
  • Angiotensinogen