What is congenital adrenal hyperplasia (CAH)?
Congenital adrenal hyperplasia (CAH) describes a group of genetic disorders affecting your adrenal glands. You have one adrenal gland on top of each kidney. The adrenal glands produce several important hormones your body needs.
In CAH, genetic mutations (changes) cause shortages of certain enzymes, such as 21-hydroxylase, that help your body produce needed hormones. For many people with CAH, the enzyme shortage causes the adrenal glands to overproduce other hormones, like testosterone.
There are two main types of CAH: classic CAH and nonclassic CAH. The symptoms depend on the type of CAH you have. There are much more rare forms of CAH with different symptoms.
Who is most at risk for getting congenital adrenal hyperplasia (CAH)?
Congenital means a condition you are born with. All forms of CAH are genetic, or inherited. To develop CAH, you must inherit certain genetic mutations from each of your parents.
How common is congenital adrenal hyperplasia (CAH)?
Classic CAH, the most common form of the disease, affects as many as 1 in every 10,000 to 15,000 people living in the U.S. and Europe. Both classic and nonclassic CAH affect people worldwide.
Symptoms and Causes
What causes congenital adrenal hyperplasia (CAH)?
Specific genetic mutations cause CAH. These genetic changes happen during a baby’s development in the womb. People living with CAH have all inherited mutated genes from their parents.
What are the symptoms of congenital adrenal hyperplasia (CAH)?
The symptoms of CAH may appear differently depending on factors including your age at diagnosis, and whether you are male or female. Each type of CAH has different symptoms.
For people living with classic CAH, symptoms occur due to a lack of the enzyme 21-hydroxylase. Doctors group classic CAH into 2 subcategories: salt-wasting CAH and simple virilizing (non-salt-wasting) CAH.
Salt-wasting CAH is the most severe form of this disease. People living with salt-wasting CAH have adrenal glands that don’t produce enough aldosterone, a hormone that helps regulate sodium (salt) levels in the body. Low levels of aldosterone result in too much sodium being lost from the body in urine.
The hormonal imbalances caused by salt-wasting CAH result in severe symptoms, including:
- Hyponatremia (low blood sodium levels)
- Cardiovascular problems, including low blood pressure and arrhythmias (heart rhythm problems)
- Low blood glucose (blood sugar)
- Metabolic acidosis (too much acid content in the blood)
Additionally, people living with salt-wasting CAH have high levels of androgens, or male sex hormones, in their bodies. Elevated androgen levels cause other symptoms, including:
- Enlarged or ambiguous (abnormal) external genitalia—for example, clitoris enlargement in a female infant
- Rapid growth
- Premature signs of puberty, including voice changes, early pubic, armpit, and facial hair, and severe acne
- Abnormal menstrual periods
- Noncancerous testicular tumors
Simple virilizing (non-salt-wasting) CAH causes a less-severe aldosterone deficiency. Androgen levels are also elevated in this type of CAH. Symptoms of simple virilizing CAH may include:
- Ambiguous (unusual) external genitalia, particularly in females
- Development of male characteristics, such as bulky muscles and a deep voice, in females or prematurely in boys
People with nonclassic CAH also have too little 21-hydroxylase enzyme activity, but this deficiency isn’t as severe as in other forms of the disease. You may be unaware you have this form of CAH because your symptoms are more mild. Children, teenagers and adults are all diagnosed with nonclassic CAH.
The symptoms of nonclassic CAH include:
- Early signs of puberty, including acne and excess facial or body hair in females
- Rapid growth in childhood and as a teenager
- Irregular menstrual periods
- Male-pattern baldness
- Early puberty changes in a boy, for example early pubic hair and an enlarged penis but with small testicles
Diagnosis and Tests
How is congenital adrenal hyperplasia diagnosed (CAH)?
In the U.S., doctors screen all newborn babies for 21-hydroxylase deficiency before they leave the hospital. This screening determines whether a child has classic CAH.
In almost all cases, doctors diagnose classic CAH in infants and young children. Diagnosis of nonclassic CAH may not occur until a person begins to show symptoms of the disease. In some cases, this may not happen until early adulthood.
Some couples at higher risk, including those with family members diagnosed with CAH, may have genetic testing to determine the risk of passing on genetic mutations to their children.
Management and Treatment
How is congenital adrenal hyperplasia treated (CAH)?
Treatment for congenital adrenal hyperplasia depends on the type of CAH you have and how severe your symptoms are. There is no cure for CAH, but many people find symptom relief with medications.
Doctors prescribe several types of medications, including salt supplements and steroids, to people living with classic CAH. Your doctor monitors your condition with regular blood tests to check hormone levels.
If classic CAH causes genital abnormalities, surgery two to six months after birth can correct the appearance of external genitalia. In some cases, it may be appropriate to delay surgery for several years.
People living with nonclassic CAH who have very mild or no symptoms may not need treatment. For some, medications like steroids or fertility drugs improve symptoms.
What complications are associated with congenital adrenal hyperplasia (CAH)?
Children living with classic CAH lose too much water and salt in their urine. They are at risk for serious complications, including imbalances of electrolytes like potassium. Left untreated, these imbalances lead to other problems, like heart arrhythmias (irregular heartbeat), cardiac arrest, and death. Untreated nonclassic CAH can lead to early puberty and short stature in a male, and permanent male type body changes in a female child, or irregular periods and infertility in a young woman.
Surgery to correct ambiguous genitalia carries its own risks for complications, including infection, bleeding and scarring.
Can congenital adrenal hyperplasia be prevented (CAH)?
There is no way to prevent congenital adrenal hyperplasia.
Outlook / Prognosis
What are the outcomes after treatment for congenital adrenal hyperplasia (CAH)?
With treatment, most people living with congenital adrenal hyperplasia lead healthy, productive lives.
When should I call my doctor?
If you become pregnant, ask your doctor about genetic testing for CAH. Your infant is tested for specific enzyme deficiencies before leaving the hospital. If you or an older child begins to experience symptoms of CAH, contact your doctor.