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Congenital adrenal hyperplasia due to 11-beta-hydroxylase deficiency
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Congenital adrenal hyperplasia due to 11-beta-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) due to 11-beta-hydroxylase deficiency is a genetic disorder affecting the adrenal glands, leading to excess male sex hormones and varying symptoms including atypical genitalia in females and hypertension.

Overview

Congenital adrenal hyperplasia (CAH) due to 11-beta-hydroxylase deficiency is one of a group of disorders (collectively called congenital adrenal hyperplasia) that affect the adrenal glands. The adrenal glands are located on top of the kidneys and produce a variety of hormones that regulate many essential functions in the body. In people with CAH due to 11-beta-hydroxylase deficiency, the adrenal glands produce excess androgens, which are male sex hormones.

There are two types of CAH due to 11-beta-hydroxylase deficiency, the classic form and the non-classic form. The classic form is the more severe of the two types.

Females with the classic form of CAH due to 11-beta-hydroxylase deficiency have external genitalia that do not look clearly male or female (atypical genitalia). However, the uterus and ovaries develop normally. Males and females with the classic form of this condition have early development of their secondary sexual characteristics such as growth of facial and pubic hair, deepening of the voice, appearance of acne, and onset of a growth spurt. The early growth spurt can prevent growth later in adolescence and lead to short stature in adulthood. In addition, approximately two-thirds of individuals with the classic form of CAH due to 11-beta-hydroxylase deficiency have high blood pressure (hypertension). Hypertension typically develops within the first year of life.

Females with the non-classic form of CAH due to 11-beta-hydroxylase deficiency have normal female genitalia. As affected females get older, they may develop excessive body hair growth (hirsutism) and irregular menstruation. Males with the non-classic form of this condition do not typically have any signs or symptoms except for short stature. Hypertension is not a feature of the non-classic form of CAH due to 11-beta-hydroxylase deficiency.

Frequency

CAH due to 11-beta-hydroxylase deficiency accounts for 5 to 8 percent of all cases of congenital adrenal hyperplasia. It is estimated that CAH due to 11-beta-hydroxylase deficiency occurs in 1 in 100,000 to 200,000 newborns. This condition is more common in Moroccan Jews living in Israel, occurring in approximately 1 in 5,000 to 7,000 newborns. The classic form of CAH due to 11-beta-hydroxylase deficiency appears to be much more common than the non-classic form.

Causes & Risk Factors

Mutations in the CYP11B1 gene cause CAH due to 11-beta-hydroxylase deficiency. The CYP11B1 gene provides instructions for making an enzyme called 11-beta-hydroxylase. This enzyme is found in the adrenal glands, where it helps produce hormones called cortisol and corticosterone. Cortisol has numerous functions, such as maintaining blood sugar (glucose) levels, protecting the body from stress, and suppressing inflammation. Corticosterone gets converted to the hormone aldosterone, which helps control blood pressure by maintaining proper salt and fluid levels in the body.

CAH due to 11-beta-hydroxylase deficiency is caused by a shortage (deficiency) of the 11-beta-hydroxylase enzyme. When 11-beta-hydroxylase is lacking, precursors that are used to form cortisol and corticosterone build up in the adrenal glands and are converted to androgens. The excess production of androgens leads to abnormalities of sexual development, particularly in females with CAH due to 11-beta-hydroxylase deficiency. A buildup in the precursors used to form corticosterone increases salt retention, leading to hypertension in individuals with the classic form of CAH due to 11-beta-hydroxylase deficiency.

The amount of functional 11-beta-hydroxylase enzyme that an individual produces typically determines the extent of abnormal sexual development. Individuals with the classic form of the condition usually have CYP11B1 gene mutations that result in the production of an enzyme with low levels of function or no function at all. Individuals with the non-classic form of the condition typically have CYP11B1 gene mutations that lead to the production of an enzyme with moderately reduced function. The severity of the signs and symptoms of sexual development do not appear to be related to the severity of the hypertension.

Associated Gene

  • CYP11B1

Inheritance

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Other Names

  • 11 beta hydroxylase deficiency
  • 11b hydroxylase deficiency
  • Adrenal hyperplasia, hypertensive form
  • Deficiency of steroid 11-beta-monooxygenase
  • P450C11B1 deficiency
  • Steroid 11 beta hydroxylase deficiency

Frequently Asked Questions

While both conditions cause adrenal androgen excess and virilization, they have opposite effects on blood pressure. Classic 21-hydroxylase deficiency causes aldosterone deficiency leading to salt-wasting crisis, dehydration, and low blood pressure. In contrast, 11-beta-hydroxylase deficiency causes an accumulation of 11-deoxycorticosterone (DOC), a potent mineralocorticoid precursor that causes fluid retention, potassium loss, and early-onset hypertension.
The primary treatment for hypertension in this disorder is adequate glucocorticoid replacement therapy, typically with hydrocortisone. Glucocorticoids suppress excessive pituitary ACTH secretion, which directly halts the adrenal overproduction of the hypertensive precursor 11-deoxycorticosterone (DOC). If blood pressure remains elevated, potassium-sparing diuretics like spironolactone or amiloride are commonly added, while standard antihypertensives that target the renin-angiotensin system are generally less effective.
Females with non-classic 11-beta-hydroxylase deficiency are born with normal female external genitalia and are usually diagnosed during adolescence or adulthood. Symptoms frequently mimic polycystic ovary syndrome (PCOS) and include persistent facial and body hair growth (hirsutism), severe cystic acne, irregular periods or absent menstruation, and reduced fertility. Hypertension is much less common and milder in the non-classic form compared to the classic form.
Because affected individuals cannot produce adequate cortisol in response to physiologic stress, they must follow strict sick-day rules during acute illness, fever, gastroenteritis, surgery, or major dental procedures. This typically involves doubling or tripling their oral glucocorticoid dose. If a patient cannot tolerate oral medication due to severe vomiting, caregivers must promptly administer an emergency intramuscular hydrocortisone injection and seek urgent hospital care.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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