Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UMLS:C0085580 (essential hypertension)
14,686 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to evaluate the correlation between sulfur amino acids (derived mainly form animal protein in the diet) and blood pressure, free amino acids, including sulfur amino acids such as taurine and methionine, were determined in the plasma and cerebrospinal fluid (CSF) of twelve normotensive subjects and twelve patients with essential hypertension under nutritional control after at least 10 days of standard hospital diet (total calorie and protein content: 2100-2300 Cal per day and 78-83 g per day, respectively). The results obtained were as follows: plasma taurine, serine, methionine and threonine were significantly lower in patients with essential hypertension than in normotensive patients. The levels of plasma taurine, serine, methionine and total sulfur amino acids in individuals correlated inversely to systolic blood pressure. No difference was observed in the CSF levels of free amino acids in normotensive and hypertensive patients. As taurine, methionine and serine are involved in the metabolism of sulfur amino acids, these observations support the view that the decrease in plasma sulfur amino acids may be a factor contributing to elevated blood pressure.
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PMID:Decrease of plasma sulfur amino acids in essential hypertension. 393 88

A higher frequency of a variant of the angiotensinogen gene characterized by a transition in exon 2 causing a replacement of methionine by threonine (M235T) has recently been found in hypertensive individuals, but not all authors were able to confirm this observation. We examined (i) 219 patients with primary hypertension, (ii) 92 normotensive controls (spouses), and (iii) a sample of the general population (blood donors, n = 139). Analysis of genomic DNA was performed by PCR amplification and alleles were separated on agarose gels. In the general population and in normotensive spouses the respective frequencies of the T and M alleles were: general population: M = 0.6, T = 0.4; normotensive spouses: M = 0.59, T = 0.41. A significantly higher frequency of the 235T allele was found in hypertensive individuals with a family history of hypertension and an onset of hypertension before 50 years of age (spouses: 0.41 versus HT with age of onset < or = 50 years and family history of HT: 0.56; P = 0.01 by chi 2). In conclusion, the present study confirms the observation of a higher frequency of the 235T allele of the angiotensinogen gene in hypertension and identifies individuals with family history and early onset of hypertension as individuals at risk.
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PMID:Association of M235T variant of the angiotensinogen gene with familial hypertension of early onset. 747 15

As part of the multicenter project entitled "Pathobiological Determinants of Atherosclerosis in Youth (PDAY)," we are testing polymorphisms in candidate genes of atherosclerosis and hypertension for associations with arterial lesions in autopsied young persons. In this study, we used temperature gradient gel electrophoresis (TGGE) to type the Met235-->Thr polymorphism in exon 2 of the angiotensinogen gene (AGT) that is associated with essential hypertension in some human populations. In addition to Met235-->Thr, we detected and sequenced four other TGGE variants in exon 2 of AGT. These included two new amino acid substitutions (Thr209-->Ile and Leu211-->Arg) that were found only among black PDAY cases. The frequency of the Ile209 mutation was 0.002 and the frequency of the Arg211 was 0.006 in 260 black PDAY cases. The other two TGGE variants were Tyr248-->Cys and a T-->C substitution at nucleotide position 171 that had been identified in previous studies. We also developed restriction isotyping for rapid typing of each AGT variant using PCR amplification and digestion with diagnostic restriction enzymes.
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PMID:Detection and characterization of new mutations in the human angiotensinogen gene (AGT). 760 42

The renin-angiotensin system regulates blood pressure and sodium balance. The angiotensinogen gene which encodes the key substrate within this system has been linked to essential hypertension in White Europeans. It has been suggested that people of West African ancestry may have a different genetic basis for hypertension. In this study we have tested whether there is linkage of the angiotensinogen gene to essential hypertension in African Caribbeans from St. Vincent and the Grenadines. DNA from 63 affected sibling pairs with hypertension was tested for linkage by analyzing whether there was excess allele sharing among siblings genotyped using an angiotensinogen dinucleotide repeat sequence. There was significant support for linkage (T = 3.07, P = 0.001) and association of this locus to hypertension (chi 2 = 50.2, 12 degrees of freedom, P << 0.001). A DNA polymorphism which alters methionine to threonine at position 235 (M235T) within the angiotensinogen peptide has been associated previously with hypertension. However, we found no association of this variant with hypertension in this study. These findings provide support for linkage and association of the angiotensinogen locus to hypertension in African Caribbeans and suggest some similarities in the genetic basis of essential hypertension in populations of different ethnicity.
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PMID:Linkage of the angiotensinogen gene locus to human essential hypertension in African Caribbeans. 763 61

Genetic approaches to understanding the pathophysiology of complex human traits, for example, hypertension, can complement physiologic analyses and are likely to improve our ability to treat or prevent the disease. A particularly useful approach is to perform linkage analysis with candidate genes using intermediate phenotypes. This has proven successful so far in identifying two genes involved in hypertension. The first was a fusion gene mutation which linked the regulatory region of the 11B-hydroxylase gene to the coding sequence for the protein of aldosterone synthetase. This mutant gene is responsible for the condition glucocorticoid-remediable aldosteronism (GRA). The intermediate phenotype used was increased levels of the adrenal steroids 18-oxo and hydroxycortisol. The gene for GRA was identified using a pedigree approach. It is likely, to identify other genes in hypertension, that the most appropriate population to be affected would be sib pairs, that is, sibling pairs who both have hypertension. In a recent study the angiotensinogen gene also was linked to hypertension in individuals who had severe or early onset hypertension. In addition, a variant of the angiotensinogen gene, substitution of threonine rather than methionine at codon 235, was specifically associated with hypertension. In a separate study, the T235 homozygote of the angiotensinogen gene was associated with the non-modulating intermediate phenotype of essential hypertension. Since converting enzyme inhibitors appear to correct the specific defect underlying the elevated blood pressure in non-modulators, identification of the gene potentially associated with non-modulation raises the strong possibility that genetic screening will allow for more specific therapy.
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PMID:Genetic approaches to understanding the pathophysiology of complex human traits. 770 3

A molecular variant of the angiotensinogen gene with threonine instead of methionine at position 235 (ie, with M235T polymorphism) has been shown to be associated with essential hypertension in Caucasian populations. The purpose of the present study was to assess whether the M235T polymorphism was associated with essential hypertension in the Japanese population. The study population consisted of 347 subjects selected in our outpatient clinic. The clinical data included in the analyses were sex, age, body mass index, cholesterol level, genotype of the angiotensinogen gene, genotype of the angiotensin-converting enzyme gene, and systolic and diastolic blood pressure. Multiple regression analysis revealed that only body mass index was a predictor of both diastolic and systolic blood pressure in these 347 subjects, but the genotype of the angiotensinogen gene was identified as a predictor of both diastolic and systolic blood pressure in a subpopulation less than 50 years of age. However, in a subpopulation more than 50 years of age, body mass index was the only predictor of both systolic and diastolic blood pressure. Of the 347 subjects, 189 had a technically excellent echocardiogram at the initial observation period. Multiple regression analysis revealed that sex, body mass index, diastolic blood pressure, and genotype of the angiotensin-converting enzyme gene were predictors of left ventricular mass. Although subjects with the TT angiotensinogen genotype had significantly greater left ventricular mass than those with either the TM or the MM genotype, the effects of the genotype of the angiotensinogen gene on left ventricular mass were mainly due to effects on blood pressure.
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PMID:Angiotensinogen gene and blood pressure in the Japanese population. 772 17

A recent cross-sectional study of HTs in Salt Lake City and Paris has reported a significant association of a T704-->C (Met235-->Thr) variant in exon 2 of the angiotensinogen gene (AGT) with essential hypertension (HT). The present study used a new, direct PCR technique to detect this variant in 92 Caucasians with severe hypertension (HT) and two HT parents and 94 normotensive (NT) controls. Although frequency of the variant in HTs (0.42) was higher than in NTs (0.39), the difference was not significant (chi 2 = 0.24; P = 0.63). Plasma angiotensinogen showed a weak, nonsignificant relationship with AGT genotype in females and no genotypic relationship was apparent for blood pressure. Thus, if the Met235-->Thr variant of AGT is involved in essential HT, then its contribution may be, at best, much weaker in other HT groups.
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PMID:Cross-sectional analysis of Met235-->Thr variant of angiotensinogen gene in severe, familial hypertension. 826 22

Genetic influences in cerebrovascular disease (CVD) may act either independently or by predisposing to, or modulating, the effect of risk factors such as hypertension. Factors involved in the pathogenesis of atherosclerosis, thrombosis and vasoconstriction are important in CVD. The angiotensinogen gene has recently been linked with essential hypertension in affected sibships and a particular polymorphism in exon 2 of the angiotensinogen gene, a threonine to methionine substitution at position 235 (M235T), has been associated with pre-eclampsia and hypertension. In this study we examined the relation of M235T polymorphism to cerebrovascular disease and carotid atheroma in 100 consecutive Caucasian patients with internal carotid artery territory ischaemia (TIA or stroke), presenting to a carotid ultrasound service. Forty five age-matched controls (mostly patients' spouses) were also studied. Hypertension was defined as current treatment with anti-hypertensive agents, or SBP > 160 mm Hg or DBP > 95 mm Hg. Twelve of 100 cases (12%) and eight of 45 controls (12%) were homozygous for the T235 allele. T:M allele ratios were 0.34:0.66 in cases and 0.34:0.66 in controls. There was no relation between the polymorphism and either internal carotid stenosis or common carotid artery intima-media thickness. In the cases, mean percentage internal carotid artery stenosis was TT 18.3 (SD 18.7)%, MT 38.0 (27.1)% and MM 36.8 (30.2)%. Mean intima-media thickness was TT 0.87 (0.18) mm, MT 0.95 (0.34) mm and MM 0.88 (0.23) mm. There was no relation between the polymorphism and hypertension (TT 11 of 100 cases, six of 45 controls).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lack of association between angiotensinogen polymorphism (M235T) and cerebrovascular disease and carotid atheroma. 852 90

Genotypic abnormalities of the renin-ANG system have been suggested as a risk factor for the development of diabetic nephropathy. Cleavage of angiotensinogen is the rate-limiting step in the activation of the renin-ANG system. The TT genotype of a polymorphism encoding threonine instead of methionine (M235T) has been associated not only with increased plasma angiotensinogen concentration but also with essential hypertension. In addition, a polymorphism in the angiotensinogen gene substituting methionine for threonine (T174M) has been associated with hypertension in nondiabetic populations. We studied the relationship between these polymorphisms in the angiotensinogen gene in IDDM patients with diabetic nephropathy (121 men, 74 women, age 40.9 +/- 10 years, diabetes duration 27 +/- 8 years). There was no difference in M235T genotype distribution between IDDM patients with diabetic nephropathy and those with normoalbuminuria: 73/97/25 (37/50/13%) vs. 67/95/23 (36/52/12%) had MM/MT/TT genotypes, respectively. No difference in distribution of T174M genotypes between nephropathic and normoalbuminuric IDDM patients was observed either: 148/44/1 (77/23/0.5%) vs. 141/42/2 (76/23/1%) had TT/TM/MM genotypes, respectively. In patients with nephropathy, systolic blood pressure was higher (161 +/- 22 mmHg [mean +/- SD]) in patients carrying TT genotype of the M235T angiotensinogen polymorphism as compared with patients with MM or MT genotypes (150 +/- 23 mmHg; P = 0.03). We conclude that neither the M235T nor the T174M polymorphism in the angiotensinogen gene contributes to genetic susceptibility to diabetic nephropathy in white IDDM patients, whereas the TT genotype of the M235T is associated with elevated blood pressure in patients with diabetic nephropathy.
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PMID:Angiotensinogen gene polymorphisms in IDDM patients with diabetic nephropathy. 859 44

The allele 235T (a threonine in place of a methionine at position 235) of angiotensinogen has been found to be associated with a predisposition to essential hypertension. We investigated whether this allele also confers increased susceptibility to nephropathy in patients with insulin-dependent diabetes mellitus (IDDM). A group of 380 patients who had had IDDM for 15 to 20 years were genotyped at the angiotensinogen 235 locus. Included were 75 patients with normoalbuminuria (albumin excretion rate < 30 micrograms/min), two series of patients with microalbuminuria (n = 30 and n = 136), and two series with overt proteinuria (n = 41 and n = 98). Allele 235T frequency was higher among cases with microalbuminuria (0.41 in the two series combined) or overt proteinuria (0.40) than in the normoalbuminuria group (0.36). However, this difference was not statistically significant with this sample size (chi 2 = 1.2, P = NS with 2 df). Under a recessive model, allele 235T homozygotes had a 1.6-fold risk of developing nephropathy relative to carriers of other genotypes, but this value was not significantly different from 1(95% CI = 0.8 to 3.5). The strength of the association did not improve after stratification by degree of glycemic control. With respect to the hypertension in these IDDM patients, no association with allele 235T was found. Allele 235T frequencies in normotensive and hypertensive individuals were 0.363 and 0.353, respectively, among normoalbuminuric IDDM individuals (chi 2 = 0.01, P = NS) and 0.411 and 0.414 among microalbuminuric IDDM subjects (chi 2 = 0.0, P = NS). We conclude that the angiotensinogen polymorphism M235T might influence susceptibility to nephropathy in insulin-dependent diabetes, but its effect, if any, is rather small and independent of hypertension.
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PMID:Angiotensinogen polymorphism M235T, hypertension, and nephropathy in insulin-dependent diabetes. 862 Dec 7


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