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Congenital Adrenal Hyperplasia Owing to 11β-Hydroxylase Deficiency

  • Perrin C. WhiteEmail author
Conference paper
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 707)

Abstract

Humans have two isozymes with 11β-hydroxylase activity that are, respectively, required for cortisol and aldosterone synthesis. CYP11B1 (11β-hydroxylase) converts 11-deoxycortisol to cortisol and 11-deoxycorticosterone to corticosterone, is expressed at high levels, and is regulated by ACTH. CYP11B2 (aldosterone synthase) is normally expressed at low levels and is regulated mainly by angiotensin II and potassium levels. In addition to 11β-hydroxylase activity, the latter enzyme has 18-hydroxylase and 18-oxidase activities and thus can synthesize aldosterone from deoxycorticosterone. Mutations in the CYP11B1 gene cause steroid 11β-hydroxylase deficiency, a form of congenital adrenal hyperplasia. Mutations in CYP11B2 result in aldosterone synthase deficiency, which can cause hyponatremia, hyperkalemia, and hypovolemic shock in infancy. These are both recessive disorders. Unequal crossing over between the CYP11B genes can generate a duplicated chimeric gene with the transcriptional regulatory region of CYP11B1 but sufficient coding sequences from CYP11B2 so that the encoded enzyme has aldosterone synthase (i.e., 18-oxidase) activity. This results in glucocorticoid-suppressible hyperaldosteronism, a form of hypertension inherited in an autosomal dominant manner. This review concentrates on steroid 11β-hydroxylase deficiency.

Keywords

Congenital Adrenal Hyperplasia Hypovolemic Shock CYP11B Gene Salt Wasting Autosomal Dominant Manner 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Copyright information

© Springer Science+Business Media, LLC 2011

Authors and Affiliations

  1. 1.Department of PediatricsUniversity of Texas, Southwestern Medical CenterDallasUSA

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