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Congenital adrenal hyperplasia

(kuhn-JEN-uh-tuhl • uh-DREEN-l • hie-puhr-PLAY-zhuh)

General Condition Information

Other Names

  • Congenital Adrenal Hyperplasia (11βMonooxygenase Deficiency)
  • Congenital Adrenal Hyperplasia due to 11-Beta-Hydroxylase Deficiency, 17 Alpha-Hydroxylase/17,20-Lyase Deficiency. 21-Hydroxylase Deficiency, 3-Beta-Hydroxysteroid Dehydrogenase Deficiency, Cytochrome P450 Oxidoreductase Deficiency

Condition Type

Birth Prevalence

  • Hundreds of babies are born with the classic form of this condition each year in the United States.
  • Visit GeneReviews to learn more about how often this condition occurs.

Screening Finding

Increased 17-OHP

What is congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is a group of inherited (genetic) conditions that can change the way your baby’s body develops and responds to stress.

Adrenal glands are small organs that produce hormones. These hormones help your body respond to illness, determine levels of salt and water in your body, and direct development of the genitals.

In CAH, certain enzymes inside the adrenal glands do not work properly. Without working enzymes, the adrenal glands do not make enough of the hormones the body needs. The adrenal glands also grow very large. The name congenital adrenal hyperplasia is given because the condition is present from birth (congenital), it affects the adrenal glands, and it makes the glands large (hyperplasia).

The form of CAH your baby has depends on which enzyme is not working. In the most common form of CAH, the enzyme 21-hydroxylase is not able to make enough of hormones called cortisol and aldosterone. This version is called CAH due to 21-hydroxylase deficiency (21-OHD).

Cortisol is important for keeping blood sugar levels normal and for protecting the body during stress. Aldosterone is important for maintaining normal salt (sodium) levels in the body.

When 21-hydroxylase is not working, pieces that should be made into cortisol and aldosterone are turned into androgens instead. Androgens are male hormones, like testosterone, which are responsible for the development of traits typically seen in men.

The two main types of CAH due to 21-OHD are:

  • Classic CAH 
  • Nonclassic CAH

Classic CAH is further broken down into two forms, known as the salt-wasting form and the simple-virilizing form. The type of CAH depends on how well 21-hydroxylase can make cortisol and aldosterone and prevent androgens from building up.

Classic CAH is the most severe form. Most babies with classic CAH have the salt-wasting form, where very little cortisol and aldosterone are made. Babies with the simple-virilizing form of classic CAH also make very little cortisol but do make some aldosterone.

Nonclassic CAH is the mildest form. The two classic forms of CAH due to 21-OHD are the forms that newborn screening assesses.

High levels of androgens, low levels of aldosterone, and low levels of cortisol can lead to the signs and symptoms of classic CAH due to 12-OHD.

There are other forms of CAH that are very rare, including: 

  • CAH due to 11-beta-hydroxylase deficiency 
  • 17 alpha-hydroxylase/17,20-lyase deficiency 
  • 3-beta-hydroxysteroid dehydrogenase deficiency 
  • Cytochrome P450 oxidoreductase deficiency

These conditions also cause a hormone imbalance due to a certain enzyme in the adrenal glands not working properly. Because these versions are not often detected by newborn screening, this page only refers to classic CAH due to 21-OHD.

Newborn Screening and Follow-Up

Condition Details

Treatment and Management

It is important to talk to your health care provider about which treatment(s) are best for your baby. The goal of treatment is to prevent the health problems caused by this condition. 

Treatments may include the following:

  • Hydrocortisone to replace the missing cortisol 
  • Fludrocortisone to maintain proper salt and fluid levels (in the salt-wasting form)
  • Salt (sodium chloride)
  • Surgery may be considered in some females with genital or urinary problems

Children who receive early and ongoing treatment for CAH can have healthy growth and development. However, children may not grow to be as tall as expected.

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