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Updated on May 10, 2024
Congenital adrenal hyperplasia (CAH) is a group of genetic disorders that affect a person’s normal growth and development. People with CAH inherit the condition from genetic mutations passed on by both biological parents. These genetic mutations can interfere with the body’s ability to produce several hormones, including cortisol, aldosterone, and sex hormones.
- Congenital means “existing from birth.” People who have CAH are born with the condition, even if symptoms do not appear until later in life.
- Adrenal refers to the adrenal glands, a pair of walnut-sized glands on top of each kidney that produce cortisol, aldosterone, and other hormones, and release these hormones into the bloodstream.
- Hyperplasia is a term that describes an increased number of cells. People with CAH often have enlarged adrenal glands that produce too little of the hormones cortisol and/or aldosterone. At the same time, the adrenal glands produce too many androgens, sometimes called the male sex hormones.
Most cases of CAH fall into two main types, classic CAH and non-classic CAH.
Classic CAH
Classic CAH is less common than non-classic CAH, but it is also the more severe form of the condition. All newborns in the U.S. are screened for classic CAH shortly after birth with a routine blood test. Prenatal screening is available for parents who are at risk for passing CAH on to a child.
Classic CAH is sometimes divided into two subtypes—salt wasting and simple virilizing. Here’s a look at what those terms mean:
Salt-wasting
- Roughly 70 to 75 percent of people who have classic CAH have this type.
- People with this type have genetic mutations that impair the adrenal glands’ ability to make both cortisol and aldosterone.
- Aldosterone helps cells maintain normal levels of water and salts. The body needs aldosterone to maintain a healthy level of sodium.
- Without enough aldosterone, sodium levels can become dangerously low. This can lead to vomiting, diarrhea, dehydration, unintended weight loss, irregular heartbeat, shock, and other serious symptoms. Without treatment, very low sodium levels can be life threatening.
- This type can also cause an excess of androgens (sex hormones) that affect physical growth and sexual maturation, a condition called virilization.
Simple virilizing
- This is the less common type and less severe type of classic CAH.
- A person with this type will have low levels of cortisol, high levels of androgens, and almost normal levels of aldosterone.
- This type also causes virilization symptoms due to the high levels of androgens.
It’s important to know that symptoms between these two subtypes overlap, and both require similar approaches to treatment.
Adrenal crisis
People with classic CAH are at risk for a complication called adrenal crisis. This occurs when levels of cortisol fall dangerously low. This affects many different organs and systems in the body, and can lead to seizures, coma, organ failure, and death. It requires emergency treatment, and people with CAH are advised to carry a medical alert ID. A healthcare provider should prescribe an emergency injection kit to be administered in case of adrenal crisis.
Non-classic CAH
This is a mild form of CAH. This type is often missed during the screening for CAH that occurs shortly after a person is born, and may not be diagnosed until later in childhood, adolescence, or during adulthood. Symptoms can include early onset of puberty, excess hair growth, deeper voice, irregular menstrual periods, and fertility problems. A person can also be asymptomatic and live with the condition for years without knowing it.
