TY - CHAP
T1 - Congenital adrenal hyperplasia owing to 11β-hydroxylase deficiency
AU - White, Perrin C.
PY - 2011
Y1 - 2011
N2 - 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.
AB - 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.
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U2 - 10.1007/978-1-4419-8002-1_2
DO - 10.1007/978-1-4419-8002-1_2
M3 - Chapter
C2 - 21691944
AN - SCOPUS:79960736650
SN - 9781441980014
T3 - Advances in Experimental Medicine and Biology
SP - 7
EP - 8
BT - Hormonal and Genetic Basis of Sexual Differentiation Disorders and Hot Topics in Endocrinology
A2 - New, Maria
A2 - Simpson, Joe Leigh
ER -