Conditions Congenital Adrenal Hyperplasia
Congenital adrenal hyperplasia (CAH) is a collection of inherited conditions that affect the body’s adrenal glands, which are the cone-shaped organs that sit on top of the kidneys. In a person with CAH, the adrenal glands are very large and are unable to produce certain chemicals, including cortisol, a chemical that helps protect the body during stress or illness and helps the body regulate the amount of sugar in the blood. Left untreated, the adrenal glands produce too much of chemicals called androgen, which produce male sex traits. Early detection and treatment can help children with CAH to have normal and healthy development.
There are some other rare forms of CAH. These forms may go by other names, including: steroidogenic acute regulartory protein deficiency (STAR), 3-beta-hydroxysteroid dehydrogenase deficiency (3B-HSD), 17-alpha-hydroxylase deficiency, 11-beta-hydroxylase deficiency, or cytochrome P450 oxidoreductase deficiency.
How common is congenital adrenal hyperplasia?
In the United States, about one in every 15,000 babies is born with congenital adrenal hyperplasia (CAH). The condition may be more or less common in certain ethnic groups and geographic regions. For example, one out of 300 babies in the Yupik Eskimo population is born with CAH. The condition is less common in people of African-American and Asian descent.
Also known as
- 21-hydroxylase deficiency
- 21-OH deficiency, adrenogenital syndrome (AG syndrome)
- c-21-hydroxylase deficiency, congenital adrenocortical hyperplasia
- Salt-losing CAH
- Attenuated CAH
- Late-onset CAH
Your baby’s doctor may ask you if your baby is showing any of the signs of CAH (see Early Signs, below). If your baby has certain signs, your baby’s doctor may suggest starting immediate treatment.
If your baby’s newborn screening result for congenital adrenal hyperplasia (CAH) was out of the normal range, your baby’s doctor or the state screening program will contact you to arrange for your baby to have additional testing. It is important to remember that an out-of-range screening result does not necessarily mean that your child has the condition. An out-of-range result may occur because the initial blood sample was too small or the test was performed too early. However, as a few babies do have the condition, it is very important that you go to your follow-up appointment for a confirmatory test. Because the harmful effects of untreated CAH can occur soon after birth, follow-up testing must be completed as soon as possible to determine whether or not your baby has the condition.
Follow-up testing will involve checking your baby’s urine and blood samples for signs of CAH. Children with CAH have high levels of a chemical called 17-OHP in their blood because they are unable to turn this chemical into cortisol, a hormone produced in the adrenal glands. High amounts of 17-OHP in the blood might indicate that your baby has CAH. Further testing, which may include genetic testing, can determine which form of CAH your child has.
About Congenital Adrenal Hyperplasia
The signs of congenital adrenal hyperplasia (CAH) vary from person to person and by the form of CAH. There are three main forms of CAH: the “salt-wasting form," the “simple virilizing form," and non-classic CAH.
Salt-wasting classic CAH accounts for about 75% of classic CAH cases. This is the most severe form. Signs of salt-wasting CAH usually begin within the first few weeks of life. These signs include:
- Poor feeding
- Sleeping longer or more often
- Weight loss
- Rapid heart rate
- Male-like genitals in females (described in detail below)
Many of these signs are caused by severe dehydration. This can be very dangerous for your child. Contact your baby’s doctor immediately if your baby has any of these signs.
Simple virilizing classic CAH accounts for about 25% of classic CAH cases. This form is less severe than salt-wasting CAH, but more severe than non-classic CAH. Signs of simple virilizing CAH begin before birth. These signs differ between males and females, which usually become apparent during childhood due to early puberty.
Early signs of simple virilizing CAH include:
- Enlarged clitoris (it may look like a small penis)
- Labia that are fused together (they may resemble a scrotum)
- Small testicles
While the majority of CAH cases are “classic,” some people are affected by non-classic CAH.
Non-classic CAH is much less severe than classic forms of CAH. Signs of non-classic CAH can begin in childhood, adolescence, or adulthood. Both males and females with non-classic CAH may show signs of early puberty. For more information about these signs, see the STAR-G’s website.
Medications and Supplements
The main form of treatment for the classic forms of congenital adrenal hyperplasia (CAH) is hydrocortisone pills. These pills help replace the cortisol that your baby’s body cannot make naturally. An endocrinologist can help determine the appropriate dosage of hydrocortisone for your baby (see Accessing Care). Patients with the salt-wasting form of CAH require additional treatment with fludrocortisone, which replaces aldosterone.
Your baby’s doctor might prescribe medications or human growth hormone supplements to help regulate your child’s growth. Children with CAH can experience delayed or rapid growth. X-rays can indicate if your child’s bones are growing too quickly. Talk to your baby’s doctor before starting this type of treatment.
Medications are also available to treat the early puberty that occurs during childhood in individuals with CAH. Your baby’s doctor can write a prescription for these hormone medications.
The genital changes associated with CAH can be reversed with surgery. Genital surgery is a very complex decision. What may be the right choice for one family might not be best for another family. It is important to talk to your baby’s doctor about the risks and benefits of genital surgery in order to make an informed decision that is right for your child and family.
If congenital adrenal hyperplasia (CAH) is treated soon after birth, children can have healthy growth and development. This is why newborn screening is so important.
Early puberty is a common sign of CAH in childhood. Children who receive treatment may still have slightly early puberty. Adults with CAH may have shorter stature than other members of their family, even with treatment.
Babies who do not receive treatment for salt-wasting CAH are at risk for coma or death.
In our bodies, enzymes help make hormones. Hormones send messages throughout the body. These messages help control various functions of the body, including growth and development. The adrenal gland makes hormones including cortisol, aldosterone, and androgens.
Cortisol helps control how the body uses sugar for energy, protects the body during injury, and regulates immune response. Aldosterone helps the body recycle salt and water from urine. Androgens are sex hormones that influence sexual development by promoting the development of male-like features.
The enzyme 21-hydroxylase (21-OH) helps the adrenal glands make cortisol and aldosterone. In 95% of congenital adrenal hyperplasia (CAH) cases, the body does not make enough 21-OH enzymes. When 21-OH does not work correctly, the levels of cortisol, aldosterone, and androgen change. Different forms of CAH have different levels of 21-OH activity. More 21-OH activity leads to less severe CAH.
Individuals with salt-wasting classic CAH have very low levels of 21-OH activity. Their levels of cortisol and aldosterone are too low, while their androgen levels are too high. The low aldosterone levels cause low levels of sodium in the blood, high levels of acid in the blood, and dehydration. While it is normal to have certain acid and sodium levels in the blood, low levels of sodium and high levels of acid can be toxic. The low sodium levels give this form its “salt-wasting” name.
Individuals with simple virilizing classic CAH have intermediate levels of 21-OH activity. Their aldosterone levels are healthy, but their cortisol levels are too low. They also have too much androgen. These babies don’t have the salt-wasting qualities described above, but they do have genital changes and experience early puberty because high androgen levels cause rapid growth and sexual development, and they promote the development of male sexual features.
Individuals with non-classic CAH have healthy levels of cortisol and aldosterone, but they have high levels of androgens. The high levels of androgens cause early puberty as described above.
About 5% of CAH cases are not caused by 21-OH deficiency. Other causes of CAH may include:
- Steroidogenic acute regulartory protein deficiency (STAR)
- 3-beta-hydroxysteroid dehydrogenase deficiency (3B-HSD)
- 17-alpha-hydroxylase deficiency
- 11-beta-hydroxylase deficiency
- Cytochrome P450 oxidoreductase deficiency
CAH is an autosomal recessive genetic condition. This means that a child must inherit two copies of the non-working gene for CAH, one from each parent, in order to have the condition. The parents of a child with an autosomal recessive condition each carry one copy of the non-working gene, but they typically do not show signs and symptoms of the condition. While having a child with CAH is rare, when both parents are carriers, they can have more than one child with the condition. Learn more about autosomal recessive inheritance.
Support for Congenital Adrenal Hyperplasia
Support groups can help connect families who have a child or other family member affected with congenital adrenal hyperplasia with a supportive community of people who have experience and expertise in living with the condition. These organizations offer resources for families, affected individuals, health care providers, and advocates.
Work with your baby’s doctor to determine the next steps for your baby’s care. Your baby’s doctor may help you coordinate care with an endocrinologist, a health care provider who treats conditions caused by problems with the endocrine glands, including the adrenal glands. Depending on the symptoms of your baby’s condition, your baby’s doctor may help you coordinate care with other medical resources in the community.
Because congenital adrenal hyperplasia (CAH) is a genetic condition, you may want to talk with a genetics specialist. A genetic counselor or geneticist can help you understand the causes of the condition, discuss genetic testing for CAH, and understand what this diagnosis means for other family members and future pregnancies. Speak with your baby’s doctor about getting a referral. The Clinic Services Search Engine offered by the American College of Medical Genetics and Genomics (ACMG) and the Find a Genetic Counselor tool on the National Society of Genetic Counselors (NSGC) website are two good resources for you or your child's health care provider to use to identify local specialists.