The frequency of the 235T and 174M alleles of the angiotensinogen gene, previously reported to be associated with hypertension in Caucasians and Japanese, was compared between 57 hypertensive African Americans and 130 normotensive African Americans sampled as part of a community survey of hypertension in the Chicago area. The frequency of the 235T allele was unrelated to hypertension status (cases, 83%, control subjects, 82%), as was true for the 174M allele. Compared with Caucasians, the frequency of the 235T allele A s an essential substrate for the renin-angiotensin system, angiotensinogen (AGT) plays an important role in hydromineral balance and the control of blood pressure.1 -4 Walker et al 5 observed a highly significant correlation between plasma AGT concentration and blood pressure in a large cross-sectional epidemiological study. Within the context of a family study, Watt and coinvestigators 6 reported higher plasma AGT levels in young adults with an elevated blood pressure whose parents also had high blood pressure compared with young adults with low blood pressure whose parents also had low blood pressure. Plasma AGT is also reported to be higher in hypertensive subjects and in the offspring of hypertensive parents. 7 In addition, overexpression of the AGT gene causes elevated blood pressure in transgenic mice carrying the rat AGT gene. 8A recent collaborative investigation of the AGT gene in siblings from Utah and Paris sharpened these findings by reporting both linkage and association of AGT molecular variants (235T and 174M) with hypertension, suggesting that these AGT polymorphisms may represent markers of an inherited predisposition to essential hypertension in humans.9 These findings have recently been extended to a Japanese population, where a significant association was also noted between hypertension and the 235T allele, along with a substantial increase in the population frequency of the 235T allele.10 Most recently, despite the failure to identify an association Received March 15, 1994; accepted in revised form June 29, 1994.From the Department of Preventive Medicine and Epidemiology, Loyola University Stritch School of Medicine (C.R., R.C.), Maywood, 111; the Department of Human Genetics, University of Utah (L.M., R.W.), Salt Lake City; and the University College Hospital, University of Ibadan (CO., E.E., M.L., B.D.) (Nigeria).Correspondence to Dr C. with either the 235T allele or the 174M allele, linkage between essential hypertension and the AGT gene has been demonstrated in a set of British families.11 The probable involvement of the AGT genomic region with blood pressure regulation is strengthened by two reports of an association between proteinuric preeclampsia and AGT polymorphisms: one with the 235T allele, 12 the other with a microsatellite polymorphism. 13 We report the findings of an investigation of the population frequency of the molecular variants 235T and 174M of the AGT gene and their association with blood pressure in samples from black populations of Chicago, 11...

The consistent relationships observed between the M235T variant and the protein product and between plasma level of the protein and hypertension status in different ethnic groups provide some evidence for a biochemical mechanism linking DNA variation in the renin-angiotensin system with the hypertension phenotype.

Abstract-Elevated blood pressure (BP) is more common in relatives of hypertensives than in relatives of normotensives, indicating familial resemblance of the BP phenotypes. Most published studies have been conducted in westernized societies.To assess the ability to generalize these estimates, we examined familial patterns of BP in a population-based sample of 510 nuclear families, including 1552 individuals (320 fathers, 370 mothers, 475 sons, and 387 daughters) from Ibadan, Nigeria. The prevalence of obesity in this community is low (body mass index: fathers, 21.6; mothers, 23.6; sons, 19.2; and daughtersϭ21.0 kg/m 2 ). The BP phenotype used in all analyses was created from the best regression model by standardizing the age-adjusted systolic blood pressure (SBP) and diastolic blood pressure (DBP) to 0 mean and unit variance. Heritability was estimated by use of the computer program SEGPATH from the most parsimonious model of "no spouse and neither gender nor generation difference" as 45% for SBP and 43% for DBP. The lack of a significant spouse correlation is consistent with little or no influence of the common familial environment. However, the heritability estimate of Ͻ50% for both SBP and DBPs reinforces the importance of the nonshared environmental effect. (Hypertension. 1999;33:874-878.)