Congenital adrenal hyperplasia, also known as CAH or 21-Hydroxylase Deficiency, is a genetic disorder of the adrenal glands.

Normally, the adrenal glands help keep the body in balance by making the right amounts of hormones, such as cortisol, aldosterone, and androgens. 

In people with congenital adrenal hyperplasia, the body doesn’t make enough of the hormone cortisol.  Their bodies may also not make aldosterone.  Instead, their adrenal glands make too much androgen. 

(View a picture of the adrenal glands and a patient education page about the adrenal glands)

Congenital adrenal hyperplasia is caused by an error on a single gene.  It is inherited, meaning it is passed down from parents to their children. Congenital adrenal hyperplasia is the most common autosomal recessive genetic disorder in humans. 

Symptoms of congenital adrenal hyperplasia range from mild to serious.  Some people with mild congenital adrenal hyperplasia might never be diagnosed because their symptoms do not cause them any problems. 

Symptoms of the mild form of CAH may include:

• Shorter height than their parents
• Early signs of puberty (in children)
• Acne
• Irregular periods and possible trouble getting pregnant (in women)
• Excess facial hair (in women)

Symptoms of the severe form of CAH may include:

• Dehydration
• Low blood pressure
• Low blood sugar level
• Trouble keeping enough salt in their bodies
• Altered development of the external genitalia in girls which is noted at birth and may require surgery to correct
• Shorter height than their parents
• Early signs of puberty (in children)
• Irregular periods and possible trouble getting pregnant (in women)
• Excess facial hair (in women)
• Benign testicular tumors and infertility (in men)

Testing for the severe form of congenital adrenal hyperplasia is now part of routine newborn screening done in most states.

Congenital adrenal hyperplasia can’t be cured, but it can be treated.  People with congenital adrenal hyperplasia can take medication to help replace the hormones their bodies are not making. Some people with congenital adrenal hyperplasia (those with the mild form) only need these medications when they are sick, while others (those with the severe form) need to take them every day for their entire life. The severe form of CAH can be life threatening without medication.

• Facts about CAH (PDF - 751 KB)