In congenital adrenal hyperplasia (CAH), a
(genetic change) causes the adrenal glands to make too little cortisol.
In the most common type of CAH, called 21-hydroxylase deficiency, the adrenal glands
also might not make aldosterone. As the adrenal glands work harder to try to make
more cortisol, they produce too much
and other androgen hormones.
What Are the Signs & Symptoms of Congenital Adrenal Hyperplasia?
symptoms will depend on a child's age, sex, and which hormones the adrenal
glands make too little or too much of.
Some types of CAH can cause a baby with female (XX)
to develop ambiguous (in-between) genitalia or genitals that appear male.
Other types can cause a baby with male (XY) chromosomes to develop genitals that appear
Newborns with untreated severe CAH usually have some of these symptoms within the
first few weeks of life:
Babies with milder forms of CAH may have no symptoms. Older kids and teens with
mild or moderate CAH may:
grow taller than average in early childhood and stop growing sooner than peers
(which may lead to a shorter than average adult height if they are not treated)
have a larger than average clitoris (girls)
not have these changes expected with puberty, or have them earlier or later than
girls — pubic and armpit hair, breast development, menstruation (periods)
boys — pubic, armpit, facial, and chest hair; voice change; increase in penis
Very mild CAH might be undiagnosed until fertility problems arise in adulthood.
What Causes Congenital Adrenal Hyperplasia?
Everyone has two copies of almost every gene.
Children with mutations in both copies of a CAH-related gene can have CAH. These mutations
cause low levels of
needed to make adrenal hormones. In the most common forms of CAH, this
leads to low levels of cortisol and sometimes also aldosterone, and high levels of
Who Gets Congenital Adrenal Hyperplasia?
People with a mutation in only one of the CAH-related genes do not have symptoms
of CAH. But they're called CAH carriers because they can pass the
CAH-causing gene to their children.
The genetic pattern through which CAH passes from parents to children is called
autosomal recessive. This means that when two CAH carriers have a
child, there is a 25% chance that the child will have CAH.
How Is Congenital Adrenal Hyperplasia Diagnosed?
A prenatal ultrasound
scan may find CAH before a baby is born. But usually it's suspected at birth or soon
after based on symptoms (such as abnormal-appearing genitals) or the results of a
blood test that's done on all newborns in the U.S.
A specialist in pediatric
usually checks the baby to see which adrenal enzyme is missing and directs
Tests that help confirm the diagnosis of CAH or guide treatment may include:
blood tests to check levels of adrenal hormones
blood chemistry to check sodium and high potassium levels in children with salt-losing
types of CAH
karyotype to determine chromosomal sex
imaging tests (such as an ultrasound study) to get more information about genital
Children with CAH are treated by a care team. The team usually includes the child's
primary care doctor, a pediatric
, a urologist, and a geneticist.
A child with severe CAH needs lifelong hormone replacement and extra cortisol during
times of illness, stress, or injury.
Treatment with hydrocortisone replaces the cortisol deficiency,
and prevents low blood sugars and low blood pressure. It can help prevent the effects
on growth and puberty that untreated CAH causes. Children with aldosterone deficiency
may need treatment with fludrocortisone (a medicine that works like
aldosterone) to maintain body salt balance. Some infants may also have to take salt
supplements by mouth.
Surgery may be considered to correct the genitals' appearance and function.
With the recommended hormone treatment and close follow-up with a pediatric endocrinologist,
children with CAH can grow and develop like other children. In adulthood, most will
be able to have children of their own.
What Else Should I Know?
Caregivers should learn when and how to give emergency treatment (such as for
a serious illness or injury), including how to give an injection of hydrocortisone,
Kids with CAH should wear a medical ID necklace or bracelet.
Genetic testing can be
done to identify CAH carriers and for prenatal diagnosis.