|
|
| (18 intermediate revisions by 4 users not shown) |
| Line 1: |
Line 1: |
| __NOTOC__ | | __NOTOC__ |
| {{Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency}} | | {{11β-hydroxylase deficiency}} |
| {{CMG}}; {{AE}} {{Ammu}}
| |
|
| |
|
| ==Overview==
| | '''For patient information, click [[{{PAGENAME}} (patient information)|here]].''' |
| '''11β-Hydroxylase deficient congenital adrenal hyperplasia''' ('''11β-OH CAH''') is an uncommon form of [[congenital adrenal hyperplasia]] resulting from a defect in the [[gene]] for the [[enzyme]] which mediates the final step of [[cortisol]] synthesis in the [[adrenal gland|adrenal]]. 11β-OH CAH results in [[hypertension]] due to excessive [[mineralocorticoid]] effects. It also causes excessive [[androgen]] production both before and after birth and can [[virilization|virilize]] a genetically female fetus or a child of either sex.
| |
|
| |
|
| ==Pathophysiology==
| | {{CMG}}; {{AE}} {{MJ}} |
| ''Congenital adrenal hyperplasia'' (CAH) refers to any of several [[autosomal]] [[recessive]] diseases resulting from defects in steps of the [[synthesis]] of [[cortisol]] from [[cholesterol]] by the [[adrenal gland]]s. All of the forms of CAH involve excessive or defective production of [[sex steroid]]s and can pervert or impair development of [[primary sex characteristic|primary]] or [[secondary sex characteristic]]s in affected infants, children, and adults. Many also involve excessive or defective production of [[mineralocorticoid]]s, which can cause [[hypertension]] or salt wasting.
| |
|
| |
|
| 11β-Hydroxylase mediates the final step of the [[glucocorticoid]] pathway, producing [[cortisol]] from 11-deoxycortisol. It also catalyzes the conversion of 11-deoxycorticosterone (DOC) to [[corticosterone]] in the [[mineralocorticoid]] pathway.
| | {{SK}} 11 beta hydroxylase deficiency; 11b hydroxylase deficiency; 11 b hydroxylase deficiency; 11b-hydroxylase deficiency; 11-b-hydroxylase deficiency; Adrenal hyperplasia, hypertensive form; Deficiency of steroid 11-beta-monooxygenase; P450C11B1 deficiency; Steroid 11 beta hydroxylase deficiency; 11 hydroxylase deficiency. |
|
| |
|
| ===Genetics=== | | ==[[11β-hydroxylase deficiency overview|Overview]]== |
| The enzyme which mediates 11β-hydroxylase activity is now known as P450c11β since it is one of the [[cytochrome P450 oxidase]] enzymes located in the inner [[mitochondrion|mitochondrial]] membrane of cells of the adrenal cortex. It is coded by a gene at 8q21-22. Like the other forms of CAH, a number of different defective alleles for the gene have been identified, producing varying degrees of impaired 11β-hydroxylase activity. Also like the other forms of CAH, 11β-OH CAH is inherited as an [[Dominance relationship#Autosomal recessive gene|autosomal recessive disease]].
| |
|
| |
|
| ==Differentiating 11β-Hydroxylase deficient congenital adrenal hyperplasia from other Diseases== | | ==[[11β-hydroxylase deficiency historical perspective|Historical Perspective]]== |
| 11β-OH CAH resembles [[congenital adrenal hyperplasia|21-hydroxylase deficient CAH]] in its [[androgen]]ic manifestations: partial [[virilization]] and [[ambiguous genitalia]] of genetically female infants, childhood virilization of both sexes, and rarer cases of virilization or [[infertility]] of adolescent and adult women. The [[mineralocorticoid]] effect differs: [[hypertension]] is usually the clinical clue that a patient has 11- rather than 21-hydroxylase CAH. Diagnosis of 11β-OH CAH is usually confirmed by demonstration of marked elevations of 11-deoxycortisol and 11-deoxycorticosterone (DOC), the substrates of 11β-hydroxylase. Management is similar to that of 21-hydroxylase deficient CAH except that mineralocorticoids need not be replaced.
| |
|
| |
|
| ==Natural History, Complications, and Prognosis== | | ==[[11β-hydroxylase deficiency classification|Classification]]== |
| ===Complications===
| |
| ====Sex steroid effects of 11β-OH CAH====
| |
| Because 11β-hydroxylase activity is not necessary in the production of [[sex steroid]]s ([[androgen]]s and [[estrogen]]s), the hyperplastic adrenal cortex produces excessive amounts of [[DHEA]], [[androstenedione]], and especially [[testosterone]].
| |
|
| |
|
| These [[androgen]]s produce effects that are similar to those of [[congenital adrenal hyperplasia|21-hydroxylase deficient CAH]]. In the severe forms, XX (genetically female) fetuses can be markedly virilized, with [[ambiguous genitalia]] that look more male than female, though internal female organs, including [[ovary|ovaries]] and [[uterus]] develop normally.
| | ==[[11β-hydroxylase deficiency pathophysiology|Pathophysiology]]== |
|
| |
|
| XY fetuses (genetic males) typically show no signs of excess androgens.
| | ==[[11β-hydroxylase deficiency causes|Causes]]== |
|
| |
|
| In milder mutations, androgen effects in both sexes appear in mid-childhood as early pubic hair, overgrowth, and accelerated bone age. Although "nonclassic" forms causing [[hirsutism]] and menstrual irregularities and appropriate steroid elevations have been reported, most have not had verifiable mutations and mild 11β-hydroxylase deficient CAH is currently considered a very rare cause of hirsutism and infertility.
| | ==[[11β-hydroxylase deficiency differential diagnosis|Differentiating 11β-hydroxylase deficiency From Other Diseases]]== |
|
| |
|
| All of the issues related to virilization, neonatal assignment, advantages and disadvantages of genital surgery, childhood and adult virilization, gender identity and sexual orientation are similar to those of 21-hydroxylase CAH and elaborated in more detail in [[Congenital adrenal hyperplasia]].
| | ==[[11β-hydroxylase deficiency epidemiology and demographics|Epidemiology and Demographics]]== |
|
| |
|
| ==Diagnosis== | | ==[[11β-hydroxylase deficiency risk factors|Risk Factors]]== |
| ===Symptoms===
| | |
| ====Mineralocorticoid aspects of 11β-OH CAH==== | | ==[[11β-hydroxylase deficiency screening|Screening]]== |
| [[Mineralocorticoid]] manifestations of severe 11β-hydroxylase deficient CAH can be biphasic, changing from deficiency (salt-wasting) in early infancy to excess ([[hypertension]]) in childhood and adult life. | |
|
| |
|
| Salt-wasting in early infancy does not occur in most cases of 11β-OH CAH but can occur because of impaired production of [[aldosterone]] aggravated by inefficiency of salt conservation in early infancy. When it occurs it resembles the salt-wasting of severe [[congenital adrenal hyperplasia|21-hydroxylase deficient CAH]]: poor weight gain and vomiting in the first weeks of life progress and culminate in life-threatening [[dehydration]], [[hyponatremia]], [[hyperkalemia]], and [[metabolic acidosis]] in the first month.
| | ==[[11β-hydroxylase deficiency natural history, complications and prognosis|Natural History, Complications and Prognosis]]== |
|
| |
|
| Despite the inefficient production of aldosterone, the more characteristic mineralocorticoid effect of 11β-OH CAH is [[hypertension]]. Progressive adrenal hyperplasia due to persistent elevation of ACTH results in extreme overproduction of 11-deoxycorticosterone (DOC) by mid-childhood. DOC is a weak mineralocorticoid, but usually reaches high enough levels in this disease to cause effects of mineralocorticoid excess: salt retention, volume expansion, and [[hypertension]].
| | ==Diagnosis== |
| | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency history and symptoms|History and Symptoms]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency physical examination|Physical Examination]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency laboratory findings|Laboratory Findings]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency CT|CT]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency MRI|MRI]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency ultrasound|Ultrasound]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency other imaging findings|Other Imaging Findings]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency other diagnostic studies|Other Diagnostic Studies]] |
|
| |
|
| ==Treatment== | | ==Treatment== |
| ===Pharmacotherapy===
| | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency medical therapy|Medical Therapy]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency surgery|Surgery]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency prevention|Prevention]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Congenital adrenal hyperplasia due to 11β-hydroxylase deficiency future or investigational therapies|Future or Investigational Therapies]] |
| As with other forms of CAH, the primary therapy of 11β-hydroxylase deficient CAH is life-long [[glucocorticoid]] replacement in sufficient doses to prevent [[adrenal insufficiency]] and suppress excess mineralocorticoid and androgen production.
| |
| | |
| Salt-wasting in infancy responds to intravenous saline, dextrose, and high dose [[hydrocortisone]], but prolonged [[fludrocortisone]] replacement is usually not necessary. The hypertension is ameliorated by glucocorticoid suppression of DOC.
| |
| | |
| Long term [[glucocorticoid]] replacement issues are similar to those of [[congenital adrenal hyperplasia|21-hydroxylase CAH]], and involve careful balance between doses sufficient to suppress androgens while avoiding suppression of growth. Because the enzyme defect does not affect [[sex steroid]] synthesis, gonadal function at puberty and long-term fertility should be normal if adrenal androgen production is controlled. See [[congenital adrenal hyperplasia]] for a more detailed discussion of androgen suppression and fertility potential in adolescent and adult women.
| |
| | |
| ==Related Chapters==
| |
| *[[Congenital adrenal hyperplasia]] for an overview of CAH, and a more detailed discussion of management issues related to the common forms of 21-hydroxylase deficiency. Nearly all of the sex steroid-related issues are the same for both 11β-hydroxylase and 21-hydroxylase deficient CAH.
| |
| *[[Lipoid congenital adrenal hyperplasia]]
| |
| *[[Congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency|Congenital adrenal hyperplasia due to 17α-hydroxylase deficiency]]
| |
| *[[Congenital adrenal hyperplasia due to 3 beta-hydroxysteroid dehydrogenase deficiency|Congenital adrenal hyperplasia due to 3β-hydroxysteroid dehydrogenase deficiency]]
| |
| *[[Intersex]] and [[ambiguous genitalia]]
| |
| *[[Adrenal insufficiency]]
| |
| | |
| | |
| [[Category:Pediatrics]]
| |
| [[Category:Endocrinology]]
| |
| [[Category:Genetic disorders]]
| |
| [[Category:Intersexuality]]
| |
| {{WikiDoc Help Menu}}
| |
| {{WikiDoc Sources}}
| |