Congenital Adrenal Hyperplasia – Symptoms and Causes

Overview

Congenital adrenal hyperplasia (CAH) refers to a collection of inherited disorders affecting the adrenal glands. These are small organs located above the kidneys. These glands produce several essential hormones that regulate various bodily functions.

When someone has CAH, a genetic mutation prevents the production of enzymes needed to make these crucial hormones.

The adrenal glands produce three main types of hormones:

• Cortisol – helps the body respond to stress and illness.
• Mineralocorticoids (like aldosterone) – regulate salt and water balance.
• Androgens (like testosterone) – control growth and sexual development.

CAH appears in two main forms:

1. Classic CAH – more severe and less common; typically identified during newborn screening or early infancy.
2. Nonclassic CAH – milder and more prevalent; often discovered during childhood or young adulthood.

While there isn’t a cure for CAH, proper medical management allows most affected individuals to live normal, healthy lives. Treatment typically focuses on replacing missing hormones and managing symptoms that may develop.

Signs and Symptoms

Common CAH shows clear symptoms that appear early in life. The body doesn’t make enough cortisol, which helps manage stress, blood sugar, and energy levels. This shortage can cause serious health problems.

Sometimes the body also lacks aldosterone, which controls salt and water balance. Without enough of these hormones, a person may experience a dangerous condition called adrenal crisis. This requires immediate medical attention.

In baby girls with common CAH, the outer genital area may look different at birth. The clitoris might be larger than usual, and parts that normally appear separate may be joined together.

Inside the body, the reproductive organs often develop normally. Baby boys with this condition usually have normal-looking genitals, though sometimes they appear larger than expected.

Physical changes from excess androgens may include:

• Rapid growth in childhood
• Early puberty signs
• Severe acne
• Short adult height
• Excess facial and body hair (in females)
• Deeper voice (in females)

Fertility challenges can occur, such as:

• Irregular or absent periods
• Difficulty becoming pregnant
• Reduced fertility in some men

Mild CAH

Mild CAH often causes no symptoms at birth. Many people with this form never develop noticeable problems. Unlike common CAH, routine newborn screening doesn’t detect this milder version.

If symptoms do appear, they typically show up during late childhood or young adulthood.

Girls born with mild CAH have normal-looking genitals at birth but may later experience:

• Irregular menstrual cycles
• Fertility difficulties
• Male-pattern hair growth
• Voice deepening

This condition is sometimes mistaken for polycystic ovary syndrome because the symptoms can be similar.

Children with mild CAH might show:

1. Early pubic hair development
2. Persistent acne problems
3. Faster-than-normal growth during childhood
4. Shorter final adult height

When to Seek Medical Care

Medical professionals usually identify common CAH through routine newborn screening tests or when they notice unusual genital appearance at birth. The condition may also be discovered when a baby becomes seriously ill from hormone deficiencies.

For children with mild CAH, parents might notice early puberty signs. If you see unusual growth patterns or development in your child, schedule an appointment with their doctor.

Adults experiencing irregular periods or fertility problems should consider getting tested for CAH.

If you’re planning to become pregnant or are already pregnant and have a family history of CAH, talk with your doctor about genetic counseling. A genetic counselor can help you understand your risk factors and what they might mean for your future children.

Causes

Congenital adrenal hyperplasia (CAH) most commonly occurs due to a deficiency of the enzyme 21-hydroxylase. This essential enzyme plays a critical role in hormone production within the body.

Without sufficient amounts of this enzyme, the body cannot produce hormones properly. In rare cases, CAH may result from deficiencies in other enzymes.

CAH is inherited through an autosomal recessive pattern. This means:

• A child must receive the altered gene from both parents to develop the condition
• Parents may carry the gene without showing symptoms
• The condition is present from birth

People who carry the CAH gene without showing symptoms are called silent carriers. These individuals can transmit the gene to their children without having CAH themselves.

The inheritance pattern works as follows:

Parents	Possibility for Child
Both parents are carriers	25% chance of CAH
One parent has CAH, one is a carrier	50% chance of CAH
Both parents have CAH	100% chance of CAH

Risk Factors

Several factors can increase the chance of having Congenital Adrenal Hyperplasia (CAH):

• Both parents have CAH
• Both parents carry the altered gene for CAH
• Ethnic background, including Ashkenazi Jewish, Latino, Mediterranean, Yugoslav, or Yup’ik ancestry

Genetic patterns play a significant role in determining who might develop this condition.

Complications

People with classic CAH may face life-threatening adrenal crisis that requires immediate medical attention. This emergency can occur shortly after birth or be triggered at any age by infections, surgery, or other physical stresses.

During adrenal crisis, dangerously low cortisol levels can cause several serious symptoms:

• Diarrhea and vomiting
• Severe dehydration
• Mental confusion
• Low blood sugar
• Seizures or convulsions
• Shock
• Coma in severe cases

Low aldosterone levels often accompany this crisis, leading to dehydration, decreased sodium, and increased potassium in the blood. It’s important to note that nonclassic CAH doesn’t typically cause adrenal crisis.

Both classic and nonclassic forms can disrupt normal menstrual patterns and create fertility challenges.

Prevention

There are currently no known methods to prevent CAH. If you have a family history of CAH and are planning to have children, it’s important to speak with your healthcare provider about your concerns.

They may recommend meeting with a genetic counselor who can help you understand the risks and options available to you.