Congenital adrenal hyperplasia (CAH) is a rare genetic condition present from birth. A person with CAH lacks one of the enzymes needed for their adrenal glands to work correctly.
Sitting above the kidneys, the adrenal glands are responsible for producing hormones that control a person’s metabolism, immune system, blood pressure, and stress response, among other purposes.
A 21-hydroxylase deficiency is the most common form of CAH and affects around 1 in 10,000 to 1 in 15,000 people annually in the United States and Europe.
In this article, we examine the types of CAH and their associated symptoms. We also look at the causes of the condition and the potential treatment options for it.
There are two main types of CAH called classic and non-classic.
Classic CAH is a rare form of the disease and is more severe than non-classic.
A person with classic CAH does not produce the enzyme known as 21-hydroxylase, which doctors usually diagnose in newborns or early infancy.
Classic CAH comes in two forms: salt-wasting and simple-virilizing.
The salt-wasting form is more severe, and the adrenal glands do not produce enough aldosterone, which regulates a person’s sodium levels. They may lose sodium in their urine, and if left undiagnosed, could result in their death, particularly in newborns.
An individual with salt-wasting CAH also has high levels of androgens in their body. Androgens are also known as male sex hormones.
The simple-virilizing form is a similar, but less severe, version of salt-wasting. It still results in low sodium levels and high levels of androgens, but it is not life threatening for newborns.
Non-classic is a less severe, but more common, form than classic CAH. It is a mild deficiency in the enzyme 21-hydroxylase.
Most of the symptoms associated with this type of CAH relate to high levels of androgens, which doctors may not detect until sometime in childhood, adolescence, or early adulthood.
Symptoms vary depending on the type of CAH a person has.
Classic CAH is usually identifiable in newborns or early childhood. Some possible symptoms for children with classic CAH include:
- an inability or difficulty to eat
- low blood pressure
- an irregular heartbeat
- low sodium and blood glucose levels
- an excess of acid in the blood
- weight loss
- ambiguous genitals in female newborns
- large genitals in male newborns
Children may also enter puberty before the average age. Indications of puberty may include:
Symptoms of non-classic CAH may be mild and are not always identifiable. Often, people may identify the condition during childhood, adolescence, or early adulthood. Symptoms of non-classic CAH may include:
- rapid growth in childhood but still having a shorter stature than parents
- early puberty
- excess body and facial hair for women
- male pattern baldness
- a large penis and small testicles
- irregular menstrual cycles
- fertility difficulties in females
Females born with CAH may present with male-looking genitalia, leading to confusion over their sex when they are born.
The increase in androgen in the body affects males and females differently. Both will experience early puberty, but males may develop a large penis, small testicles, acne, and a deep voice. Females may experience irregular periods, a deep voice, and facial hair.
The National Institute of Child Health and Human Development (NICHD) states that fertility problems may affect
CAH occurs as a result of a deficiency in the enzyme 21-hydroxylase. This deficiency results in the adrenal glands producing too little sodium and too much androgen.
CAH is usually the result of an inherited genetic abnormality. Although both parents may be healthy, it is still possible they are carrying a gene for the disease that they may or may not pass on to their child.
However, in some people, CAH can result from a non-inherited, or random, gene mutation.
If both parents carry a CAH gene, they have a 25% chance of passing it on to each child. They do not need to have CAH themselves.
Research suggests a high prevalence of CAH in the U.S. Ashkenazi Jewish community.
A 2022 review suggests that individuals of Hispanic, Latino, or Caucasian ethnicity are more likely to have CAH than those of Black or African descent.
Individuals with the classic form of CAH may be at risk of adrenal crisis. This is life threatening and can occur in newborns with CAH. Additionally, a person with classic CAH can have an adrenal crisis following physical stress or an illness.
Females with CAH may also develop fertility problems.
A newborn may receive a diagnosis almost immediately following birth. This will likely happen if they have unusual genitals that make it difficult to identify the baby’s sex.
Newborns are often subject to screening for this disorder. However, non-classic CAH may not always be detectable during screening.
A healthcare professional may conduct a hormonal exam or a blood test to diagnose the condition.
Some people may wish to screen their child for CAH before birth if they have reason to believe their child may be at risk. Healthcare professionals can test for CAH using a blood test.
There is no cure for CAH, but a person can manage it.
Hormone specialists, called endocrinologists, and urologists carefully monitor newborns and children with classic CAH. Doctors can stabilize a person’s electrolyte levels before undergoing aldosterone replacement therapy.
A person may need to take cortisol and aldosterone medications daily. In addition, people with CAH may be subject to regular blood tests to monitor their hormone levels.
The outlook for a person with non-classic CAH is generally positive. Non-classic CAH is less severe, and people may go through life without knowing they have the condition.
Classic CAH is manageable with the appropriate treatment and monitoring. However, an adrenal crisis could be fatal.
CAH is usually detectable by a doctor at birth if it is severe.
If a person’s child has entered puberty prematurely, they should consider taking them to see a doctor.
People who are pregnant and believe they may be at risk of passing on the CAH gene may wish to contact a doctor for advice.
Congenital adrenal hyperplasia is a condition that causes the adrenal glands to produce too much androgen, the male sex hormone. This may result in early puberty and other symptoms.
There are two main types of CAH called classic and non-classic.
Classic is more serious, but it is treatable and manageable if a doctor identifies it at birth or early infancy. Non-classic is less severe, and a person may not detect this condition until later in life.