Understanding Congenital Adrenal Hyperplasia

Reviewed by: HU Medical Review Board | Last reviewed: May 2024

Congenital adrenal hyperplasia (CAH) is a group of rare genetic disorders that affect the adrenal glands. The adrenal glands are 2 walnut-sized organs located above the kidneys. They produce essential hormones that keep the body functioning well. CAH is often present at birth and can lead to health challenges throughout life.1-3

There are 2 types of CAH:1

  • Classic CAH – This is the rarer type of CAH. It is usually found in early infancy or through tests performed shortly before or at birth.
  • Nonclassic CAH – This is the more common type of CAH. It is milder and may not be discovered until childhood or early adulthood.

What causes congenital adrenal hyperplasia?

Congenital adrenal hyperplasia is caused by genetic mutations (changes) to genes that make enzymes the adrenal glands need in order to produce hormones. These enzymes help the adrenal glands produce the following hormones:1-3

  • Cortisol
  • Mineralocorticoids, such as aldosterone
  • Androgens, such as testosterone

The most common cause of CAH is the lack of a specific type of enzyme protein called 21-hydroxylase. It accounts for 95 percent of CAH cases. Other, much less common causes of CAH are:1-3

Who does congenital adrenal hyperplasia affect?

People with CAH are born with the condition. It is an autosomal recessive disorder, which means both parents must carry the defective gene in order for their child to inherit the condition.1-3

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CAH is rare. It affects about 1 in 15,000 births worldwide. It occurs in both males and females.1,3

People of certain ethnicities are more likely to have CAH than others, including people who are:1,3

  • Ashkenazi Jewish
  • Latino
  • Mediterranean
  • Yugoslavian
  • Yup’ik Eskimo

What are the symptoms of congenital adrenal hyperplasia?

The symptoms of CAH can vary depending on the severity of the condition and the specific enzyme deficiency that a person has. Because CAH causes a hormonal imbalance, it can lead to many different symptoms.1

In classic CAH, symptoms may include:1

  • Abnormally low cortisol levels – This can affect blood pressure, blood sugar, and energy levels.
  • Adrenal crisis – A lack of cortisol, aldosterone, or both, which can be life-threatening.
  • Atypical external genitals – In female infants, genitals may look different. Certain female genitalia, like the clitoris or the labia, might be enlarged and resemble male genitalia. In male infants, genitals may look typical, but they may be enlarged.
  • Abnormally high androgen levels – This can lead to early puberty and more severe acne in both males and females. And in females, higher androgen levels can lead to developing more masculine features such as an increase in body hair and a deeper voice.
  • Faster growth and development – Children with CAH may have quicker growth and development. This can mean earlier puberty and more developed bones. However, the final height of a child with CAH might be shorter than average.
  • Fertility problems – Hormones are crucial when it comes to fertility. So, when there is an imbalance of hormones like in people with CAH, there can be a reduction in fertility.

Nonclassic CAH causes fewer symptoms. And many people with nonclassic CAH may never have any symptoms. For males and females who do have CAH symptoms, they may include:1

  • Early puberty
  • Serious acne
  • Early bone growth
  • Shorter overall height

For females in particular, nonclassic CAH symptoms may include:1

  • Irregular or no menstrual cycle
  • Increased body or facial hair
  • Deeper voice
  • Fertility issues

How is congenital adrenal hyperplasia diagnosed?

CAH can be diagnosed before or after a baby is born, during childhood, or later in life. Diagnostic tests that can confirm a CAH diagnosis include:5

  • Amniocentesis – This is a prenatal test that checks the amniotic fluid that surrounds an unborn baby in the womb. The amniotic fluid and cells from the uterus can be analyzed for genetic abnormalities.
  • Blood and urine tests – These tests check for hormonal imbalances that might indicate CAH.
  • Genetic testing – This checks to see if you have the genetic mutation that causes CAH.

Early detection of CAH is crucial for it to be managed well. In the United States, newborns are routinely tested for CAH within the first few days of life. This is done with a simple blood test. It can confirm a classic CAH diagnosis but not the nonclassic form of CAH.5

Treatment for congenital adrenal hyperplasia

There is no cure for CAH, but there are treatment options. Treatment for CAH focuses on lowering or replacing hormones to restore the hormonal imbalance and help manage symptoms. This is done with medicines that reduce androgen production and replace missing hormones in order to balance hormone levels.5

Medicines to treat CAH may include:5

  • Steroids
  • Mineralocorticoids
  • Salt supplements

For female infants with atypical external genitals, reconstructive surgery may be considered to help the genitals function better and look more typical. This surgery can be done between 3 and 6 months of age. But some parents may decide to delay surgery or wait until their child is old enough to understand what the surgery entails and be a part of the decision-making process.5

Treatment for CAH requires a personalized approach. With a comprehensive treatment plan, people with CAH can lead fulfilling lives.5

Consider screening

CAH is a complex genetic disorder that can present in infancy or childhood. Early detection through newborn screening and advancements in treatment options have greatly improved outcomes for people with CAH. Genetic counseling is recommended for families with a history of CAH to help them better understand the risks and make informed decisions.5

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