| Juvenile hypertension, the role of genetically altered steroid metabolism. | |
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MedLine Citation:
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PMID: 11740142 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The importance of hypertension in the pediatric population is not as well appreciated as in adults. This might be related in part to the lower prevalence of high blood pressure in this age group. As with height and weight, blood pressure increases with age during childhood. The underlying causes of significant hypertension in children differ considerably from those in adults: while the prevalence of hypertension in pediatrics is lower than in adults, clinically identifiable causes of hypertension are common. Abnormalities in steroid biosynthesis have been known for years to cause hypertension in some cases of congenital adrenal hyperplasia. In these patients, hypertension usually accompanies a characteristic phenotype with abnormal sexual differentiation. Recently, the molecular basis of four forms of severe hypertension transmitted on an autosomal basis has been elucidated: (a) the glucocorticoid-remediable aldosteronism (GRA), (b) the syndrome of apparent mineralocorticoid excess (AME), (c) activating mutation of the mineralocorticoid receptor and (d) Liddle's syndrome. All these conditions are characterized primarily by low or low-normal plasma renin, normal or low serum potassium and salt-sensitive hypertension, indicating an increased mineralocorticoid effect. These forms of juvenile hypertension are a consequence of abnormal biosynthesis, metabolism or action of steroid hormones: (a) GRA is due to expression of a chimeric gene produced by fusion of 11beta-hydroxylase aldosterone-synthase genes. Expression of the chimeric enzyme occurs in the zona fasciculata of the adrenal cortex under the control of ACTH and can be suppressed by administration of glucocorticoids. (b) AME is caused by mutations of the 11beta-hydroxysteroid dehydrogenase type 2 enzyme, an enzyme that metabolizes cortisol into its receptor inactive keto-form cortisone, thus protecting the mineralocorticoid receptor (MR) from occupation by glucocorticoids. (c) The activating mutation of the MR results in constitutive MR activity and alters receptor specificity, with progesterone and other steroids lacking 21-hydroxyl groups becoming potent agonists. (d) Liddle's syndrome is due to mutations in the beta or gamma chain of the epithelial sodium channel in distal renal tubule cells. The hyperactivity of this channel caused by the mutations results in increased sodium reabsorption. With the advent of molecular biology in clinical practice it has become evident that some genetic defect may present with a more discrete phenotype, with only moderate hypertension with or without hypokalemia as presenting feature. Considering that hypertension in children and adolescents is often 'nonessential', a search for disorders should be integral part of the diagnostic work-up in young patients with hypertension. |
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Authors:
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P Ferrari; M Bianchetti; F J Frey |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Review |
Journal Detail:
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Title: Hormone research Volume: 55 ISSN: 0301-0163 ISO Abbreviation: Horm. Res. Publication Date: 2001 |
Date Detail:
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Created Date: 2001-12-12 Completed Date: 2002-02-05 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0366126 Medline TA: Horm Res Country: Switzerland |
Other Details:
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Languages: eng Pagination: 213-23 Citation Subset: IM |
Copyright Information:
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Copyright 2001 S. Karger AG, Basel |
Affiliation:
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Division of Nephrology and Hypertension, Inselspital, University of Bern, Switzerland. paolo.ferrari@insel.ch |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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11-beta-Hydroxysteroid Dehydrogenases Aldosterone Synthase / genetics Child Epithelial Sodium Channel Humans Hydroxysteroid Dehydrogenases / genetics Hypertension / genetics*, physiopathology* Mutation / physiology* Receptors, Mineralocorticoid / genetics Sodium Channels / genetics Steroid 11-beta-Hydroxylase / genetics Steroid 17-alpha-Hydroxylase / genetics Steroids / metabolism, physiology* |
| Chemical | |
Reg. No./Substance:
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0/Epithelial Sodium Channel; 0/Receptors, Mineralocorticoid; 0/Sodium Channels; 0/Steroids; EC 1.1.-/Hydroxysteroid Dehydrogenases; EC 1.1.1.146/11-beta-Hydroxysteroid Dehydrogenases; EC 1.14.15.4/Aldosterone Synthase; EC 1.14.15.4/Steroid 11-beta-Hydroxylase; EC 1.14.99.9/Steroid 17-alpha-Hydroxylase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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