If you or your child has been diagnosed with congenital adrenal hyperplasia (CAH), you likely have many questions. What causes CAH? What are the symptoms? What treatments are available?

Read on to learn eight key facts about CAH — including the different types, common symptoms, how it’s diagnosed, and current treatment options.

1. CAH Causes Hormone Imbalances

CAH is a group of conditions that affect the adrenal glands — walnut-sized glands located on top of the kidneys. These glands make several important hormones, including:

• Glucocorticoids (such as cortisol) — Help regulate the body’s response to stress and illness, as well as blood pressure, blood sugar, and energy levels
• Mineralocorticoids (such as aldosterone) — Help control blood pressure and maintain the right balance of salt and water in the body
• Androgens — A group of sex hormones (such as testosterone) that influence growth, development, and the appearance of certain secondary sexual characteristics during puberty

People with CAH are born with a shortage or absence of an enzyme the body needs to make one or more of these hormones. An enzyme is a type of protein that helps build or break down substances in the body.

2. CAH Is Caused by Genes Inherited From Your Parents

CAH is a genetic condition, passed from parents to children through changes (also called variants or mutations) in a specific gene.

It follows an autosomal recessive inheritance pattern. This means a person can carry a genetic change for CAH without showing any symptoms — this is called being an “unaffected carrier.” A child must inherit a copy of the changed gene from both parents to develop CAH. In most cases, both parents of a child with CAH are either unaffected carriers or also have the condition themselves.

3. Most People With CAH Have 21-Hydroxylase Deficiency

According to the National Organization for Rare Disorders, about 95 percent of CAH cases are caused by a shortage or absence of an enzyme called 21-hydroxylase. This is the most common enzyme deficiency linked to CAH, which is why both classic and nonclassic CAH often refer specifically to 21-hydroxylase deficiency.

There are two main types of CAH: classic CAH and nonclassic CAH.

Classic CAH is the more severe form and can be life-threatening if not treated. It includes two subtypes of classic CAH:

• Salt-wasting CAH — A form that affects the body’s ability to regulate salt and water levels
• Simple-virilizing CAH — Does not cause salt loss but still leads to hormone imbalances, including excess androgen production

Most people with classic CAH have the salt-wasting subtype, which is also the most severe. People with nonclassic CAH usually have milder symptoms and often don’t experience symptoms until later in childhood or adolescence.

Other Types of CAH

In rare cases, CAH is caused by a shortage or absence of a different enzyme that the adrenal gland needs to produce hormones. These less common forms of CAH include:

• 11-beta-hydroxylase deficiency
• 17-alpha-hydroxylase deficiency
• 3-beta-hydroxysteroid dehydrogenase deficiency
• Lipoid congenital adrenal hyperplasia

4. CAH Is Rare

According to the National Organization for Rare Disorders, CAH affects about 1 in every 10,000 to 15,000 people in the United States and Europe. The nonclassic form is more common, affecting about 1 in every 100 to 200 people. Other types of CAH are rarer.

A person is at higher risk of having CAH if both parents either have the condition or are carriers of a gene variant that causes CAH.

According to Mayo Clinic, some racial and ethnic groups have a higher risk of developing CAH, including people who are:

• Ashkenazi Jewish
• Latino
• Mediterranean
• Yugoslav
• Yup’ik

5. CAH Symptoms Vary Depending on the Type

Symptoms of CAH can vary based on several factors, including:

• The type of CAH (classic or nonclassic)
• How severe the hormone imbalance is
• The person’s sex at birth

Signs and Symptoms of Classic CAH

Hormone imbalances in classic CAH can cause a range of symptoms. High levels of androgens may lead to:

• Atypical genitalia in female infants
• Enlarged penis with relatively small testicles
• Early puberty
• Development of typically male physical traits in females, such as increased muscle mass, facial hair, or a deep voice
• Rapid growth during childhood
• Irregular or absent menstrual periods
• Benign (noncancerous) testicular growths called testicular adrenal rest tumors (TARTs)
• Infertility (difficulty getting pregnant or getting someone pregnant)

Low levels of aldosterone in salt-wasting classic CAH can cause issues with salt and water balance, such as:

• Dehydration
• Low blood volume
• Hypotension (low blood pressure)

Low cortisol levels in classic CAH can lead to a life-threatening condition called an adrenal crisis. Symptoms of adrenal crisis include:

• Weakness
• Stomach pain
• Nausea and vomiting
• Hypotension
• Rapid heart rate
• Confusion
• Loss of consciousness or coma

Signs and Symptoms of Nonclassic CAH

Some people with nonclassic CAH may have no symptoms at all. When symptoms do occur, they often relate to changes in puberty or sexual development, such as:

• Early puberty
• Rapid growth in childhood
• Acne
• Irregular menstrual periods
• Hirsutism (excess facial hair or body hair)
• Pattern baldness (typically along the hairline or crown)

What Are the Long-Term Health Consequences of Congenital Adrenal Hyperplasia?

People with CAH may face long-term health challenges, depending on the type and severity of their condition.

According to Mayo Clinic, women with classic CAH may have trouble getting pregnant, irregular menstrual periods, or no periods at all. Some women with nonclassic CAH experience infertility, Mayo Clinic notes.

Men with classic CAH can also experience fertility issues related to this genetic condition, according to Mayo Clinic.

Because of the risk of adrenal crisis, people with classic CAH are advised to wear a medical ID card or bracelet. These IDs provide important information about their condition and the emergency medications and doses needed if they become ill, injured, or unconscious.

6. Newborns Are Tested for CAH

In the United States and many other countries, newborn screening includes a test for CAH. This test looks for classic 21-hydroxylase deficiency. Most babies with classic CAH are diagnosed at birth or shortly after.

If a baby is at high risk of developing CAH — for example, if both parents are carriers — prenatal testing may be offered during pregnancy.

Newborn screening doesn’t usually detect other types of CAH, including nonclassic 21-hydroxylase deficiency. These types may not be diagnosed until symptoms appear later in infancy, childhood, or early adulthood.

To check for CAH in children and adults, a healthcare provider may:

• Perform a physical exam
• Ask about symptoms and medical history
• Check blood pressure and heart rate
• Order blood and urine tests to measure hormone and salt levels
• Recommend genetic testing to confirm a diagnosis
• Use X-rays or other imaging tests to evaluate bone development in children

7. Treatment for CAH Involves a Team of Specialists

Managing CAH often requires a team of healthcare professionals who have experience treating this complex condition. Your care team may include:

• Endocrinologist — A doctor who specializes in hormone-related conditions
• Urologist — A specialist in urinary tract and genital conditions
• Psychologist or mental health professional — To support emotional and mental well-being
• Geneticist — A doctor who diagnoses and helps manage inherited conditions
• Reproductive endocrinologist — A specialist in hormone-related fertility issues

Because CAH affects people differently, your treatment needs may change over time. Regular follow-up appointments and blood tests help make sure your treatment stays effective and that your hormone levels are well managed.

8. CAH Treatment May Include Medications, Surgery, and Other Support

CAH treatment is personalized based on the type and severity of the condition, as well as the individual’s needs, preferences, and health goals. Some people with nonclassic CAH or mild symptoms may not need treatment. In general, the goal of CAH treatment is to correct hormone imbalances and support overall well-being.

Medications for CAH

Medications help restore hormone balance by lowering excess androgens and providing enough cortisol and, when needed, aldosterone. Treatment options may include:

• Glucocorticoids such as hydrocortisone
• Mineralocorticoids such as fludrocortisone
• Salt supplements (especially in infants with salt-wasting CAH)
• Crinecerfont (Crenessity) — A newer medication for CAH that may allow for lower doses of glucocorticoids

People with classic CAH typically need to take daily medications for life. During times of illness, injury, or physical stress, they may require higher doses.

People with nonclassic CAH may not need medication at all — or may only require low doses of glucocorticoids.

It’s important to understand the possible side effects of CAH medications and work closely with a healthcare provider to find the right treatment balance.

Surgery for CAH

Some people with CAH may have genitals that appear or function differently from what is typically expected. In these cases, adults with CAH or caregivers of children with CAH may consider surgery to modify genital appearance or function.

Surgical decisions are highly personal and sometimes controversial. Surgery is often approached as a shared decision between individuals with CAH (or caregivers of children) and the healthcare team.

Some families choose to delay surgery until the child is old enough to participate in decisions about their own body.

Other Support for CAH

Living with CAH can impact mental health, especially during childhood and adolescence. Psychologists or mental health professionals can provide support for social and emotional challenges related to the condition.

Children with CAH may also benefit from nutritional support to support healthy growth and development.

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