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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Family and population studies have reported that blood pressure has a heritability of 30-50%, but simple genetic models do not readily explain the patterns of inheritance of hypertension. 2. Restriction fragment length polymorphisms were used to study allele frequencies of a selection of candidate genes that may be important in determining the genetic component of hypertension. These included the genes for renin, haptoglobin, neuropeptide Y and cardiac myosin beta heavy chain. 3. There was no significant association between alleles at any of these loci and the presence of hypertension in this population, suggesting that the contribution of variation at these loci to the genetic component of the variance in hypertension may be quite small.
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PMID:Polymorphisms of candidate genes in essential hypertension. 135 2

A genetic influence on the variability of blood pressure in populations has been established. This effect has been demonstrated repeatedly by the presence of familial aggregation of blood pressure; however, a unique bimodal distribution in populations has not been established. About one-third to one-half of the blood pressure variance is explained by heredity with the remainder due to environmental or unknown factors. Direct associations of blood pressure with genetic markers in populations have been described infrequently. However, an association between haptoglobin 1 and increased blood pressure has been reported. This relationship is possibly secondary to increased sodium sensitivity in this genetic subgroup. The familial aggregation of urinary kallikrein as well as sodium-lithium countertransport and hypertension represents a successful attempt by investigators to identify correlates of intermediate phenotypes of hypertension. The association between restriction fragment length polymorphisms and elevated blood pressure represents an unmet potential. It should be emphasized that any genetic predictive factor will be affected by environmental factors. This interaction provides the opportunity for possible modification or prevention of hypertension by hygienic means.
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PMID:Predictors of hypertension. Population studies. 178 36

Human essential hypertension is a family of diseases; one subtype has an increased maximum velocity for red blood cell lithium-sodium countertransport activity. To begin the localization of the gene or genes responsible for this phenotype, we examined the association of blood pressure, lithium-sodium countertransport, and two genetic markers previously associated with hypertension--the MN blood group antigen (chromosome 4) and the plasma protein haptoglobin (chromosome 18)--in a population-based sample of 592 young adults from Tecumseh, Mich., the site of an ongoing cardiovascular epidemiological investigation. Our results suggest that the relation between MN phenotype and systolic blood pressure is significantly different and oppositely directed in men and women. Analysis of data available from previous examinations revealed that similar blood pressure differences related to MN phenotype had been present at least a decade earlier in both men and women. There also was a significant relation between systolic blood pressure and haptoglobin phenotype for the combined group of men and women. In addition to having high systolic blood pressure, men with the MM phenotype had significantly elevated red blood cell lithium-sodium countertransport activity. In studies of brother-brother pairs, we found evidence for significant genetic linkage between the MN locus and red blood cell lithium-sodium countertransport activity.
Hypertension 1991 Jun
PMID:Linkage of MN locus and erythrocyte lithium-sodium countertransport in Tecumseh, Michigan. 204 79

Hypertension that occurs before the age of 60 years is strongly aggregated in families, mostly due to genetic factors with weaker contributions from a shared family environment. Hypertension is probably a heterogeneous collection of overlapping subsets of pathophysiological mechanisms, such as dyslipidemia, obesity, hyperinsulinemia and cation metabolism. Highly heritable traits such as sodium-lithium countertransport, urinary kallikrein excretion and a body fat pattern index show evidence of major gene segregation in families with hypertension. They are thought to be intermediate phenotypes in the chain of pathophysiological events leading from specific genes to the distant phenotype of hypertension. They provide evidence of measurable contributions from single gene traits to the susceptibility to hypertension. Genetic linkage studies have suggested that other specific loci (e.g. histocompatibility leukocyte antigen, blood group MN and the haptoglobin protein) contribute to the susceptibility to hypertension. DNA sequencing has shown a point mutation for lipoprotein lipase that conveys susceptibility to lipid abnormalities, and possibly also hypertension, as seen in families with dyslipidemic hypertension. Further application of these approaches, especially in families that include multiple siblings with hypertension, shows promise of a true understanding of how the combined effects of a few specific genes, the polygenic background and selected environmental factors can lead to essential hypertension. This understanding should foster better tailored and more effective approaches to the prevention, diagnosis and treatment of hypertension.
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PMID:Multigenic human hypertension: evidence for subtypes and hope for haplotypes. 209 95

Human arterial hypertension is likely a multifactorial trait resulting from multiple measurable monogenes, blended polygenes, shared family environment, and individual environment. Familial aggregation of hypertension and familial correlation of blood pressure appears to be more due to genes than to shared family environment. Total genetic heritability of 80% with some recessive major gene effects have been found for several traits associated with hypertension including urinary kallikrein excretion, intraerythrocytic sodium, and sodium-lithium countertransport. Other interesting factors regarding hypertension genetics include: non-modulation of the renin angiotensin system, intralymphocytic sodium, ionized calcium, and several genetic markers such as haptoglobin, HLA, and MNS blood type. Probably the most clinically useful information regarding the genetics of hypertension is evolving in several studies reporting a strong association of hypertension with dyslipidemia, diabetes, and obesity.
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PMID:Genetics of hypertension: what we know and don't know. 220 56

Essential hypertension is a heterogeneous group of disorders with different causes. This report reviews approaches taken and results found in current studies of the genetic and environmental determinants of essential hypertension. Recent observations from the University of Utah Cardiovascular Genetics Research Clinic and published data from other studies are cited. Several biochemical tests show strong associations with hypertension and substantial major gene and/or polygenic determination including: urinary kallikrein excretion, intracellular sodium concentration, sodium-lithium countertransport, plasma haptoglobin phenotypes, MN blood groups, and familial dyslipidemia.
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PMID:Definition of genetic factors in hypertension: a search for major genes, polygenes, and homogeneous subtypes. 246 8

Confirmation of a causal relationship between hemolytic-uremic syndrome (HUS) and verotoxin-producing Escherichia coli (VTEC) infection is provided by the case of a 22-year-old West German woman. The patient presented with fatigue, nausea, and headache. Ultrasonography revealed enlarged kidneys, and laboratory investigations showed uremia, hemolytic anemia, lactate dehydrogenase, haptoglobin below the detection limit, and thrombocytopenia. She received hemodialysis and drug treatment (heparin, dopamine, and furosemide). To investigate the kinetics of the humoral response to verotoxin, the patient was followed for 3 months. Fecal specimens on day 23 yielded E coli serotype 0111:NM, and stool filtrates on days 16 and 23 showed highly cytotoxic activity for HeLa cells. While the patient's initial serum showed a high IgM immune response against purified Shiga toxin, there was a steady decline in IgM and steady increase in IgG antibodies over the ensuing 3 months. These findings are suggestive of a recent infection by a verotoxin-producing organism. This is the 1st reported case of VTEC-associated HUS with e coli 0111 infection in an adult, and the patient's 4-year history of oral contraceptives (OCs)--ethinyl estradiol and chlormadinoneacetate--is considered to be of etiologic significance. The diminished antibody coating of bacteria in the urinary tract of OC users may have facilitated invasion of verotoxin across the mucosal barrier in this patient. Severe hypertension has been reported previously in OC users with HUS. It is speculated that verotoxin may trigger HUS in longterm OC users, initiating vasoconstriction and microangiopathic hemolysis.
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PMID:Hemolytic-uremic syndrome associated with an infection by verotoxin producing Escherichia coli 0111 in a woman on oral contraceptives. 328 32

Dietary salt reduction is an important nonpharmacologic remedy for mild hypertension as well as a useful adjunct to drug treatment. However, a reduced salt intake diet is not effective in reducing the blood pressure of all hypertensive patients. Several lines of evidence indicate that some patients are salt-sensitive whereas others are salt-resistant. A series of investigations have been conducted showing that the blood pressure responses to either acute salt and volume loading or to a reduced dietary salt intake are normally distributed. Blood pressure, humoral regulators of blood pressure and renal sodium handling are each found to be influenced by genetic variance. The change in blood pressure from dietary salt reduction is influenced by genetic variance as well. Definitions of salt sensitivity and resistance were formulated, and salt sensitivity of blood pressure was found to occur significantly more often in black than in white Americans. Furthermore, preliminary data suggest that measurement of phenotypes of haptoglobin in blood may assist in identifying salt-sensitive and salt-resistant subjects. Trials of a reduced salt intake diet in pharmacologically treated hypertensive patients are currently being conducted. The data suggest that at least half of the patients are salt-sensitive and that their medications may be reduced in response to the intervention. Results of this study may be of relevance to many of the 60 million Americans with hypertension, particularly to those who are black and elderly.
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PMID:Heritable aspects of salt sensitivity. 338 25

Sodium sensitivity and resistance of blood pressure were examined in 117 normotensive and 85 hypertensive subjects by means of a protocol using rapid extracellular fluid volume expansion with intravenously administered saline (2 L over 4 hours) followed by a day of low dietary sodium intake (10 mEq) and volume contraction induced by a diuretic (furosemide, 120 mg orally). Genetic markers were also examined. Both hypertensive and normotensive subjects with haptoglobin 1-1 phenotype were significantly more (p less than 0.05) likely to be sodium-sensitive than were those with 2-1 or 2-2 phenotypes, and subjects with 2-2 phenotypes were more apt to be sodium-resistant. A second population was examined in which both adults and children with haptoglobin 1-1 phenotype were found to have significantly (p less than 0.05) higher casual systolic and diastolic blood pressures. These two studies independently confirm a relationship between haptoglobin phenotypes and blood pressure and suggest an environmental factor (sodium) as well.
Hypertension 1987 Oct
PMID:Association of haptoglobin with sodium sensitivity and resistance of blood pressure. 365 73

Blood samples from 257 hypertensive patients and 180 normotensive controls were analysed for their association with haptoglobin levels and phenotypes. Compared to controls, patients with Hp 2-2 phenotype showed a significantly increased risk for essential hypertension (p less than 0.001) and hypertension associated with ischaemic heart disease (p less than 0.05). There was a significant decrease in the mean levels of serum haptoglobins in hypertension as compared to controls, suggesting the possibility for intravascular haemolysis due to vascular damage leading to further complications.
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PMID:Haptoglobin patterns in essential hypertension and associated conditions--increased risk for Hp 2-2. 367 34


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