Congenital adrenal hyperplasia - Symptoms and causes (2024)


Adrenal glands

Congenital adrenal hyperplasia - Symptoms and causes (1)

Adrenal glands

Located on top of each kidney, the adrenal glands make hormones that help regulate metabolism, the immune system, blood pressure and other important functions. Although small, these glands control much of what happens in the body.

Congenital adrenal hyperplasia (CAH) is the medical name for a group of genetic conditions that affect the adrenal glands. The adrenal glands are a pair of walnut-sized organs above the kidneys. They make important hormones, including:

  • Cortisol. This controls the body's response to illness or stress.
  • Mineralocorticoids such as aldosterone. These control sodium and potassium levels.
  • Androgens such as testosterone. These sex hormones are needed for growth and development in both males and females.

In people with CAH, a gene change results in a lack of one of the enzyme proteins needed to make these hormones.

The two major types of congenital adrenal hyperplasia are:

  • Classic CAH. This type is rarer and more serious. It's usually found by tests at birth or in early infancy.
  • Nonclassic CAH. This type is milder and more common. It may not be found until childhood or early adulthood.

There is no cure for congenital adrenal hyperplasia. But with proper treatment, most people who have CAH can lead full lives.


Symptoms of CAH vary. The symptoms depend on which gene is affected. They also depend on how greatly the adrenal glands lack one of the enzymes needed to make hormones. With CAH, the hormones that the body needs to work properly are thrown out of balance. That may lead to too little cortisol, too little aldosterone, too many androgens or a mix of these issues.

Classic CAH

Symptoms of classic CAH can include:

  • Not enough cortisol. With classic CAH, the body doesn't make enough of the hormone cortisol. This can cause problems keeping blood pressure, blood sugar and energy at healthy levels. It also can cause problems during physical stress such as illness.
  • Adrenal crisis. People with classic CAH can be seriously affected by a lack of cortisol, aldosterone or both. This is known as an adrenal crisis. It can be life-threatening.
  • External genitals that don't look typical. In female infants, some parts of the genitals on the outside of the body may look different than usual. For instance, the cl*tor*s may be enlarged and resemble a penis. The labia may be partly closed and look like a scrotum. The tube through which urine leaves the body and the vagin* may be one opening instead of two separate openings. The uterus, fallopian tubes and ovaries often develop in a typical manner.

    Male infants with CAH often have genitals that look typical but sometimes are enlarged.

  • Too much androgen. An excess of the male sex hormone androgen can lead to short height and early puberty for children. Pubic hair and other signs of puberty may appear at a very early age. Serious acne also may occur.

    Extra androgen hormones in females may lead to facial hair, more body hair than usual and a deeper voice.

  • Altered growth. Children may grow fast. And their bones could be more developed than is typical for their age. Final height may be shorter than average.
  • Fertility issues. These can include irregular menstrual periods or not having periods at all. Some women with classic CAH may have trouble becoming pregnant. Fertility issues sometimes can occur in men.

Nonclassic CAH

Often, there are no symptoms of nonclassic CAH when a baby is born. Some people with nonclassic CAH never have symptoms. The condition is not found on routine infant blood screening tests. If symptoms occur, they usually appear in late childhood or early adulthood.

Females who have nonclassic CAH may have genitals that look typical at birth. Later in life, they may have:

  • Irregular menstrual periods, or none at all.
  • Trouble getting pregnant.
  • Features such as facial hair, more body hair than usual and a deeper voice.

Sometimes, nonclassic CAH may be confused with a hormonal condition that happens during the reproductive years called polycystic ovary syndrome.

Nonclassic CAH symptoms in children of either birth sex also can include:

  • Symptoms of early puberty, such as growth of pubic hair sooner than usual.
  • Serious acne.
  • Rapid growth during childhood with bones that are more developed than is typical.
  • Shorter than expected final height.

When to see a doctor

Most often, classic CAH is found at birth through routine newborn screening tests. Or it's found when a baby's outer genitals do not look typical. CAH also may be detected when infants show symptoms of serious illness due to low levels of cortisol, aldosterone or both.

In children who have nonclassic CAH, symptoms of early puberty may appear. If you have concerns about your child's growth or development, schedule a checkup with your child's healthcare professional.

In older people who have irregular periods, trouble getting pregnant or both, screening for CAH may be appropriate.

If you are planning pregnancy or are pregnant and may be at risk of CAH, ask your healthcare professional about genetic counseling. A genetic counselor can tell you if your genes might affect you or any children you decide to have.

Request an appointment


Autosomal recessive inheritance pattern

Congenital adrenal hyperplasia - Symptoms and causes (2)

Autosomal recessive inheritance pattern

To have an autosomal recessive disorder, you inherit two changed genes, sometimes called mutations. You get one from each parent. Their health is rarely affected because they have only one changed gene. Two carriers have a 25% chance of having an unaffected child with two unaffected genes. They have a 50% chance of having an unaffected child who also is a carrier. They have a 25% chance of having an affected child with two changed genes.

The most common cause of CAH is the lack of the enzyme protein known as 21-hydroxylase. Sometimes, CAH is called 21-hydroxylase deficiency. The body needs this enzyme to make proper amounts of hormones. Very rarely, a lack of other much rarer enzymes also can cause CAH.

CAH is a genetic condition. That means it's passed from parents to children. It's present at birth. Children with the condition have two parents who both carry the genetic change that causes CAH. Or they have two parents who have CAH themselves. This is known as the autosomal recessive inheritance pattern.

People can carry the CAH gene and not have symptoms of the condition. This is called being a silent carrier. If a silent carrier becomes pregnant, that person can pass the gene to a child. If tests show that you're a silent carrier of the CAH gene and you have a partner of the opposite sex, talk with your healthcare professional. It's likely that your partner will need to get tested for the CAH gene before pregnancy so that you can better understand the risks.

Risk factors

Factors that raise the risk of having CAH include:

  • Parents who both have CAH.
  • Parents who are both carriers of the changed gene that causes CAH.
  • Being of Ashkenazi Jewish, Latino, Mediterranean, Yugoslav or Yup'ik descent.


People who have classic CAH are at risk of a life-threatening condition called adrenal crisis. This emergency needs to be treated right away. Adrenal crisis can happen within the first few days after birth. It also can be triggered at any age by an infectious illness or physical stress such as surgery.

With adrenal crisis, very low levels of cortisol in the blood can cause:

  • Diarrhea.
  • Vomiting.
  • Dehydration.
  • Confusion.
  • Low blood sugar levels.
  • Seizures.
  • Shock.
  • Coma.

Aldosterone also may be low. This leads to dehydration, low sodium and high potassium levels. The nonclassic form of CAH doesn't cause adrenal crisis.

People who have either classic or nonclassic CAH may have irregular menstrual cycles and fertility issues.


There is no known way to prevent CAH. If you're thinking of starting a family and you're at risk of having a child with CAH, talk with your healthcare professional. You may be told to see a genetic counselor.

By Mayo Clinic Staff

Congenital adrenal hyperplasia - Symptoms and causes (2024)


Congenital adrenal hyperplasia - Symptoms and causes? ›

The most common cause of CAH is a genetic mutation (change) in the 21-hydroxylase enzyme. The adrenal gland needs 21-hydroxylase to make appropriate amounts of hormones. If someone doesn't have enough 21-hydroxylase, called 21-hydroxylase deficiency, this can result in decreased cortisol production.

What is the common cause of congenital adrenal hyperplasia? ›

The most common cause of CAH is a genetic mutation (change) in the 21-hydroxylase enzyme. The adrenal gland needs 21-hydroxylase to make appropriate amounts of hormones. If someone doesn't have enough 21-hydroxylase, called 21-hydroxylase deficiency, this can result in decreased cortisol production.

How do you explain congenital adrenal hyperplasia? ›

Congenital adrenal hyperplasia (CAH) is an inherited disorder of the adrenal glands that can affect both boys and girls. The adrenal glands are located above the kidneys and produce three types of hormones: Cortisol, which regulates energy, blood pressure and blood sugar and helps us recover from a sudden illness.

What is the key defect in congenital adrenal hyperplasia? ›

The most common cause of CAH is the lack of the enzyme protein known as 21-hydroxylase. Sometimes, CAH is called 21-hydroxylase deficiency. The body needs this enzyme to make proper amounts of hormones. Very rarely, a lack of other much rarer enzymes also can cause CAH .

What is 4 congenital adrenal hyperplasia? ›

Congenital Adrenal Hyperplasia (CAH) is a term used to describe a group of genetically determined disorders of defective steroidogenesis that result in variable deficiency of the end products cortisol and/or aldosterone and their deleterious, including life-threatening, effects on metabolism and electrolytes with ...

What is the life expectancy of someone with congenital adrenal hyperplasia? ›

CAH is a fairly uncommon diagnosis, but one which is well understood and for which good treatment is readily available. People with CAH enjoy excellent health and the condition does not impact on life expectancy. They can do anything they want to, including building careers, forming relationships and having children.

How do you fix congenital adrenal hyperplasia? ›

Classic CAH is treated with steroids that replace the low hormones.
  1. Infants and children usually take a form of cortisol called hydrocortisone.
  2. Adults take hydrocortisone, prednisone, or dexamethasone, which also replace cortisol.
Feb 13, 2024

What happens if congenital adrenal hyperplasia is not treated? ›

In this type of CAH, the adrenal glands make too little aldosterone, causing the body to be unable to retain enough sodium (salt). Too much sodium is lost in urine (thus the name, "salt-wasting"). If undiagnosed, symptoms of classic salt-wasting CAH appear within days or weeks of birth and, in some cases, death occurs.

What are the long term effects of congenital adrenal hyperplasia? ›

Important long-term health issues for adults with CAH affect both men and women. These issues may either be due to the disease or to steroid treatment and may affect final height, fertility, cardiometabolic risk, bone metabolism, neuro-cognitive development and the quality-of-life.

Does congenital adrenal hyperplasia cause weight gain? ›

Some children complain of increased appetite with medication increases, and oversuppression can cause excess weight gain. Even once the oversuppression is eliminated, excess weight may still continue to be a problem.

What is the diet for congenital adrenal hyperplasia? ›

For children with congenital adrenal hyperplasia, as with all children, a diet rich in fruits and vegetables and low in processed foods and saturated and trans fats can help to maintain health and ensure growth and development.

Which hormonal inadequacy is associated with congenital adrenal hyperplasia? ›

21-hydroxylase deficiency is one of a group of disorders known as congenital adrenal hyperplasias that impair hormone production and disrupt sexual development. 21-hydroxylase deficiency is responsible for about 95 percent of all cases of congenital adrenal hyperplasia.

What is the most severe form of congenital adrenal hyperplasia? ›

Salt-wasting CAH: Salt-wasting is the most severe form of CAH. If you have salt-wasting CAH, your adrenal glands produce too little aldosterone. Without enough aldosterone, your body can't regulate the salt (sodium) levels in your blood.

What is the cause of death in congenital adrenal hyperplasia? ›

In both genders it can lead to salt-wasting. Congenital lipoid adrenal hyperplasia may cause early death due to adrenal crisis. Males have ambiguous genitalia. Both males and females, if they survive, would likely be infertile.

What hormone causes adrenal hyperplasia? ›

CAH is caused by three disturbances: Too little cortisol (pronounced KAWR-tuh-sawl). The adrenal glands of infants born with CAH cannot make enough of the hormone cortisol. This hormone affects energy levels, blood sugar levels, blood pressure, and the body's response to stress, illness, and injury.

How do you test for adrenal hyperplasia? ›

An ACTH stimulation test is used to diagnose congenital adrenal hyperplasia and determine the type your child has. Blood samples are taken before and after giving your child an injection of synthetic ACTH, or adrenocorticotropic hormone, which signals the adrenal glands to release the hormone cortisol.

What type of congenital adrenal hyperplasia is most common? ›

The most common form of CAH, 21 hydroxylase deficiency, affects approximately 1:10,000 to 1:15,000 people in the United States and Europe. Among Yupik Eskimos, the occurrence of the salt-wasting form of this disorder may be as high as 1 in 282 individuals. Other forms of CAH are much rarer.

What is the most common mutation in congenital adrenal hyperplasia? ›

Congenital adrenal hyperplasia most commonly results from mutations or deletions of CYP21A. This mutation produces a 21-hydroxylase deficiency in 90%-95% of adrenal hyperplasia cases. Mutations or partial deletions that alter CYP21A also are common.

What is the most common cause of bilateral adrenal hyperplasia? ›

In 80% of cases, it is due to an over-secretion of the adrenal corticotrophin hormone (ACTH) by a corticotroph pituitary adenoma, or more rarely, by a neuroendocrine tumor.

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