Congenital adrenal hyperplasia

Also known as

  • CAH
  • 21 Hydroxylase Deficiency

CAH refers to a group of disorders that are present at birth (congenital) and where the adrenal glands are larger than usual (hyperplasia). In CAH production of the hormone cortisol (hydrocortisone) from the adrenal glands is impaired.

Condition details

Cortisol is released at times of emotional and physical stress and is important for several body processes, such as maintaining blood sugar levels. The condition also causes the hormone androgen (the hormone responsible for production of testosterone) to be over produced, which causes male characteristics to appear early in boys or inappropriately in girls. The severity of the condition can vary. Boys with a severe form will show symptoms at about ten days of age with vomiting, dehydration and weight loss (known as a salt-losing crisis). Girls with a severe form will have ambiguous (non-feminised) genitalia at birth due to the effect of androgen over production in the developing baby. These girls will also develop a 'salt-losing crisis' unless treated quickly. Boys and girls with a mild form will have symptoms later in childhood with tall stature, early development of pubic hair, enlargement of the penis or clitoris, but no salt-losing crisis.

I would like to edit or add detail to this database entry

Photos of affected individuals

Click images to enlarge.

  • No baby imageBaby
  • No toddler imageToddler
  • No child 4-10 imageChild 4-10
  • No child 10-18 imageChild 10-18
  • No adult imageAdult

Typical age range of first manifestation

  • Can manifest in Baby
  • Does not manifest in Toddler
  • Can manifest in Child 4-10
  • Does not manifest in Child 10-18
  • Does not manifest in Adult


Affected genes identified to date

  • CYP21A2

Inheritance patterns

Is Autosomal recessive

Are carriers affected?

How many are affected?

Support groups and organisations


Known experts

No experts found

I would like to edit or add detail to this database entry

Please let us know more about you

In order to allow you to edit this form, please fill in the fields below and click submit to proceed to to the editing page.

used only if we have questions about your entry.

Share this page

Welcome to the GDUK network

If this is the first time you have searched for information on a particular condition, details you find here may be distressing.

» If you would rather read our Newly Diagnosed section for parents and carers first click here