Disorder Name: Congenital Adrenal Hyperplasia
This fact sheet contains general information about congenital adrenal hyperplasia (CAH). Every child is different and some of these facts may not apply to your child specifically. Certain treatments may be advised for some children but not others.
There are a number of different inherited causes of CAH. This fact sheet describes 21-hydroxylase deficiency (21-OHD) which accounts for about 95% of all cases of CAH. The other causes of CAH are not covered in this fact sheet but are listed at the end.
What is CAH?
CAH stands for “congenital adrenal hyperplasia”. CAH is an inherited condition that affects the adrenal glands and causes a number of specific health issues.
‘Congenital’ means the condition is present at birth. The adrenal glands are cone-shaped organs that sit on top of each kidney. They make a number of hormones necessary for healthy body function. Hyperplasia means ‘overly large’. In people with CAH, the adrenal glands cannot make enough of a hormone called cortisol. As they start working harder in attempts to make more cortisol they increase in size, resulting in hyperplasia.
Babies with CAH are born with a number of physical changes. Their adrenal glands are often larger than normal, even at birth. Girls with CAH may be born with external sex organs that appear more masculine than they should. If not treated, both boys and girls will develop early sexual characteristics, well before normal puberty should begin.
What causes CAH?
Normally, the adrenal glands make a number of different hormones, including cortisol, aldosterone and androgens. Hormones are chemicals that send messages to other organs or tissues of the body, telling them to do specific things.
CAH occurs when a particular enzyme called 21-hydroxylase (21-OH) is missing or not working correctly. The job of this enzyme is to help make cortisol and aldosterone in the adrenal glands so they can be released when the body needs them.
One of the main jobs of cortisol is to keep the amount of glucose, the sugar used for energy by the body’s cells, at a normal level. Cortisol also helps protect the body during times of physical or emotional stress such as surgery, injury or illness. It helps to regulate the immune response and inflammation so our bodies can deal with infection or illness.
Another hormone made by the adrenal glands is aldosterone. This hormone is released into the blood when the blood pressure drops too low. It tells the kidneys to pull salt and water out of urine and put it back into the blood. This raises blood pressure back to normal and prevents the body from losing too much fluid. Babies with a form of CAH called “salt-wasting’ do not make enough aldosterone and they lose too much salt and water in their urine. They become dehydrated and their blood pressure drops too low. This can be life-threatening if not treated quickly.
The other hormones made by the adrenal glands are called androgens. These are male-like sex hormones. The adrenal glands also make a small amount of female hormones.
Most people with CAH make too much of the androgen hormones and not enough cortisol or aldosterone. Having too much of the androgen hormones in the blood causes female babies to develop masculine changes to their genitals. And, high levels of androgens lead to early sexual development, well before the normal age of puberty, in both boys and girls.
If CAH is not treated, what problems occur?
The effects of CAH can vary greatly from person to person. There are a number of different forms of CAH which are described below.
Most babies found to have CAH during newborn screening have ‘classic CAH’. One type of classic CAH is called ‘salt-wasting’ which is a serious condition needing immediate treatment. The other type of classic CAH is called ‘simple virilizing’. Children with this type do not have immediate risks to their health but still need treatment.
A small number of children are found through newborn screening to have ‘nonclassic CAH’ which often causes fewer health problems. The symptoms of nonclassic CAH are quite variable from person to person.
Classic CAH – “Salt-wasting form”
Infants with salt-wasting CAH usually show some of the following features within the first few weeks of life:
If not treated, severe dehydration leads to shock, a serious situation in which not enough blood is getting to the brain and other organs. In babies with salt-wasting CAH, this is also called an "adrenal crisis”. The signs of an adrenal crisis include:
Periods of adrenal crisis due to too little aldosterone can occur as early as one week to one month of age. If a child in shock is not treated, there is a risk of death.
Even when carefully treated, children with salt-wasting CAH are still at risk for adrenal crises when they become ill or are under stress. The body needs more than the usual amount of adrenal hormones during illness, injury or stress. This means a child with CAH must be given more medication during these times to prevent an adrenal crisis.
All babies with salt-wasting CAH have the other features of classic CAH listed below. Girls with salt-wasting CAH usually have more male-like changes to their genitals than girls with simple virilizing CAH.
Classic CAH starts its effects before birth. Excess androgen hormones are made by the fetus. This causes the genitals of female fetuses to develop male-like features. Baby girls born with classic CAH often have an enlarged clitoris. In some girls this is not very noticeable, but in others it may look like a small penis. Baby girls may also have labia which are fused together, may be wrinkled and may look more like a male scrotum. Some baby girls have fewer genital changes than others. The degree of male-like change is not something that can be predicted before birth. The high level of androgen hormones does not affect the uterus and ovaries, which develop normally.
Girls who are not treated may develop other male-like traits and behaviors as they grow. Some of these changes may include:
Boys who are not treated may have some of the following traits:
Sometimes the changes of early puberty happen in boys and girls as young as two to four years old. Both boys and girls may have rapid growth during childhood but end up being quite short as adults. Excess androgen hormones in childhood cause the rapid growth. The androgens also cause shorter adult height by closing the growth plates too soon.
Some untreated adults also have problems with infertility and may have difficulty achieving pregnancy.
Children with simple virilizing CAH are not at risk for severe adrenal crises like those with salt-wasting form. However, illness or stress increases the body’s need for cortisol. If children with CAH do not receive increased amounts of medication during illness or stress, they are at risk for healthy problems.
Nonclassic CAH / Late-onset CAH
Babies with nonclassic CAH are usually healthy at birth and their genitals are normal in appearance. They do not have salt-wasting and are not at risk for adrenal crises.
Children and adults with nonclassic CAH have adrenal glands that make near-normal amounts of cortisol and normal amounts of aldosterone. However, they have too much 17-OHP, a chemical used to make cortisol, in their blood. They also make make too much of the androgen hormones.
Some of the traits that are sometimes seen in both males and females with nonclassic CAH include:
Girls and women may have:
Boys may have:
What is the treatment for CAH?
Your baby’s primary doctor may work with a pediatric endocrinologist to provide medical care to your child. It is important for babies with classic CAH to be diagnosed as quickly as possible. This allows treatment to begin soon after birth which helps reduce the effects of CAH.
The main treatment for classic CAH is a drug called ‘hydrocortisone’ (also called ‘cortisone’), taken in pill form. This medication replaces the cortisol that your baby cannot make on his or her own. It must be taken daily throughout life to prevent effects of CAH.
Treatment for Classic CAH – both simple virilizing and salt-wasting forms:
It is important to always follow your doctor's orders on how much cortisone to give your child. Too much cortisone can cause temporary symptoms of Cushing syndrome so the dose must be carefully balanced to your child’s height, weight and activity level. Signs of Cushing syndrome include: stretch marks on the skin, rounded face, weight gain, high blood pressure, and bone loss.
In addition, always call your doctor at the start of any illness. The body needs more cortisol during illness, injury or times of stress. Therefore, the cortisone dosage must be increased by your doctor when your child is ill, injured or under emotional or physical stress. If your child is ill and cannot take the pills, cortisone injections may be necessary.
Your doctor may advise you to carry an emergency treatment letter with steps for your child’s care during stress or illness. Children with CAH should also consider wearing a Medic-Alert bracelet.
Hydrocortisone must be taken throughout life to prevent CAH effects. If the medication is stopped, symptoms will develop.
Surgery for girls with classic CAH
If you choose corrective surgery, it can be done as early as age one to three. Surgery on the clitoris usually hides the excess tissue but leaves the clitoris itself intact. Surgery to separate the labia and to create a normal vagina is often delayed until the teenage years. Ask your doctor about the risks and benefits of surgery for these changes and the best time to do these surgeries.
Treatment to prevent short stature
Specific medications may help increase height in children and teens that show signs of early growth failure. Certain medications lower androgen levels. For other children, human growth hormone, given by injection, helps increase adult height. If you have questions about your child’s growth, talk to your doctor about the costs and benefits of these treatments.
Treatment for early puberty
Additional treatment for classic CAH – salt-wasting form
Some children with salt-wasting CAH need to follow a food plan that contains more salt than usual. In addition, your doctor may recommend salt tablets to prevent dehydration. It is important to follow your doctor’s instructions on how much salt to feed your child. Some children on medication do not need to add extra salt to their diets.
Treatment for nonclassic CAH
Children and adults with nonclassic CAH usually need less medication than children with classic CAH.
What happens when CAH is treated?
Children with CAH who start treatment soon after birth usually have normal growth and development. In most treated children, puberty occurs at the normal age, although some still have early changes. Even when treated, some adults are shorter than average.
Girls on medication usually have normal menstrual periods. Pregnancy is possible, although fertility may be lessened in some women.
Children with salt-wasting CAH who remain on treatment usually do not have further salt-wasting adrenal crises or other associated health problems.
Pregnant women with classic salt-wasting CAH should be followed carefully by an endocrinologist during pregnancy. Medications may need to be increased during pregnancy to prevent problems with fetal growth.
What causes the21-hydroxylase enzyme to be absent or not working correctly?
Genes tell the body to make various enzymes. People with CAH have a pair of genes that do not work correctly. Because of the changes in this pair of genes, the 21-OH enzyme either does not work properly or is not made at all.
How is CAH deficiency inherited?
CAH is inherited in an autosomal recessive manner. It affects both boys and girls equally.
Everyone has a pair of genes that make the 21-OH enzyme. In children with CAH, neither of these genes works correctly. These children inherit one non-working gene for the condition from each parent.
Parents of children with CAH rarely have the condition themselves. Instead, each parent has a single non-working gene for CAH. They are called carriers. Carriers do not have CAH because the other gene of this pair is working correctly.
When both parents are carriers, there is a 25% chance in each pregnancy for the child to have CAH. There is a 50% chance for the child to be a carrier, just like the parents. And, there is a 25% chance for the child to have two working genes.
Genetic counseling is available to families who have children with CAH. Genetic counselors can answer your questions about how CAH is inherited, choices during future pregnancies, and how to test other family members. Ask your doctor about a referral to a genetic counselor.
Is genetic testing available?
DNA testing is not always necessary to diagnose your child but it can sometimes be helpful in determining whether your child has classic or nonclassic CAH. It can also be helpful for carrier or prenatal testing, discussed below.
What other testing is available?
CAH is confirmed by testing the level of 17-OHP and other substances in the blood. Other blood and urine tests may also be necessary to determine whether you child has the salt-wasting form of CAH. Talk to your doctor or your genetic counselor if you have questions about testing for CAH.
Nonclassic CAH is confirmed through testing a blood sample for the levels of 17-OHP and other adrenal hormones.
Can you test during pregnancy?
Parents may choose to have testing during pregnancy or wait until birth to have the baby tested. A genetic counselor can talk to you about your choices and answer questions about prenatal testing or testing your baby after birth.
Treatment during pregnancy
Can other members of the family have CAH or be carriers?
Each of the parents’ brothers and sisters has a 50% chance to be a carrier. It is important for other family members to be told that they could be carriers. There is a small chance they are also at risk to have children with CAH.
A few states do not offer newborn screening for CAH. However, expanded newborn screening through private labs is available for babies born in states that do not screen for this condition. To learn whether your state screens for CAH, see http://genes-r-us.uthscsa.edu/.
When both parents are carriers, newborn screening results are not sufficient to rule out the condition in a newborn baby. In this case, special diagnostic testing should be done at birth in addition to newborn screening.
Can other family members be tested?
How many people have CAH?
Does CAH happen more frequently in a certain ethnic group?
CAH occurs in people of all ethnic groups around the world. It is more common in the Yupik Eskimos; about 1 in 300 babies in this population is born with CAH. It is less common in African-American and Asian people.
Does CAH go by any other names?
CAH is sometimes also called:
The nonclassic form of CAH is sometimes also called:
Some less common causes of CAH not discussed in this fact sheet are:
Where can I find more information?
Being told your child has CAH can be a very stressful experience for the whole family. Your health care practitioners can help you deal with some of the feelings, concerns and questions that naturally come up when a baby is diagnosed with CAH. There are also national support groups and other organizations that provide written information about CAH. Many of these groups have volunteers who can talk with you by phone or by email about your feelings and concerns and may be able to connect you with other parents who have children with CAH. Some of these support networks and organizations are listed below.
CARES (Congenital Adrenal Hyperplasia Research, Education and Support) Foundation, Inc.
National Adrenal Diseases Foundation
MAGIC Foundation (Major Aspects of Growth in Children)
Congenital Adrenal Hyperplasia Education and Support Network
Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency: A guide for patients and their families
National Library of Medicine Genetics Home Reference (CAH)
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