Disease: Congenital adrenal hyperplasia

Overview

Congenital adrenal hyperplasia (CAH) is a group of inherited genetic disorders that affect the adrenal glands, a pair of walnut-sized organs above your kidneys. A person with CAH lacks one of the enzymes the adrenal glands use to produce hormones that help regulate metabolism, the immune system, blood pressure and other essential functions.

CAH affects the production of one or more of three steroid hormones: cortisol, which regulates your body's response to illness or stress; mineralocorticoids, such as aldosterone, which regulate sodium and potassium levels; or androgens, such as testosterone, which are sex hormones. In many cases, CAH results in lack of cortisol and overproduction of androgen.

The milder and more common form of CAH is called nonclassic. The classic form, which is more severe, can be detected in newborn screening programs. Some forms of CAH can cause problems with normal growth and development in children and even be life-threatening.

Although there is no cure, with proper treatment, most people with congenital adrenal hyperplasia can lead normal lives.

Source: http://www.mayoclinic.com

Symptoms

Signs and symptoms of congenital adrenal hyperplasia vary, depending on which gene is defective and the level of enzyme deficiency.

There are two major types of congenital adrenal hyperplasia:

  • Classic CAH. This more-severe form of the disease is usually detected in infancy.
  • Nonclassic CAH. This milder and more common form may not become evident until childhood or early adulthood.

Classic CAH

Approximately two-thirds of people with classic CAH are classified as having the salt-losing form, while one-third have the simple-virilizing form. In both forms, affected females have genital ambiguity.

A child with classic CAH may experience:

  • A lack in the production of cortisol in both the salt-losing and simple-virilizing forms. Most of the problems caused by classic CAH are related to a lack of cortisol, which plays an important role in regulating your blood pressure, maintaining blood sugar and energy levels, and protecting your body against stress.
  • A lack in the production of aldosterone in the salt-losing form. This can lead to low blood pressure, a lower sodium level and a higher potassium level. Sodium and potassium normally work together to help maintain the right balance of fluids in your body.
  • Excess production of the male sex hormones (androgens such as testosterone). This can result in short height, early puberty and in females, abnormal genital development while in the womb.

Signs and symptoms of classic CAH in infants include:

  • In females, enlarged clitoris or genitals that look more male than female (ambiguous genitalia) at birth, but males have normal appearing genitals
  • Significant illness related to a lack of cortisol, aldosterone or both (adrenal crisis), which can be life-threatening

Signs and symptoms of classic CAH in children and adults include:

  • Very early appearance of pubic hair
  • Rapid growth during childhood, but shorter than average final height

Nonclassic CAH

This form of CAH is milder than classic CAH. Often there are no symptoms at birth. The condition is not identified on routine infant blood screening and often only becomes evident in late childhood or early adulthood. Hormone deficiency may only involve cortisol levels.

Although teenage and adult females may have normal appearing genitals at birth, later signs and symptoms often include:

  • Irregular or absent menstrual periods
  • Masculine characteristics such as facial hair, excessive body hair and a deepening voice
  • Severe acne

In both females and males, signs and symptoms of nonclassic CAH also may include:

  • Early appearance of pubic hair
  • Rapid growth during childhood, but shorter than average final height

When to see a doctor

Classic CAH is usually detected at birth through required newborn screening or when female babies show ambiguous genitalia. CAH may also be identified when male or female babies show signs of severe illness due to low levels of cortisol, aldosterone or both.

In nonclassic CAH, you may notice signs and symptoms of early puberty in your toddler or child. In this case, or if you have concerns about your child's growth or development, make an appointment with your child's pediatrician.

If you're pregnant and may be at risk of CAH because of your own medical history or your ethnicity, ask your doctor about genetic counseling.

Source: http://www.mayoclinic.com

Causes

In 95 percent of cases, the enzyme lacking in congenital adrenal hyperplasia is 21-hydroxylase. CAH may sometimes be called 21-hydroxylase deficiency. There are other much rarer enzyme deficiencies that also cause CAH.

CAH is passed along in an inheritance pattern called autosomal recessive. Children who have the condition have two parents who either have CAH themselves or who are both carriers of the genetic mutation that causes the condition.

Source: http://www.mayoclinic.com

Diagnosis

Diagnosis of congenital adrenal hyperplasia may include the following tests.

Prenatal testing

Tests to diagnose CAH in fetuses can be done when siblings have the disease or family members are known to carry the gene defect. One of these tests may be done:

  • Amniocentesis. This procedure involves using a needle to withdraw a sample of amniotic fluid from the womb, and then examining the cells.
  • Chorionic villus sampling. This test involves withdrawing cells from the placenta for examination.

Newborns, infants and children

All newborns in the United States are screened for classic CAH caused by genetic 21-hydroxylase deficiency during the first few days of life. This test does not identify nonclassic CAH.

Diagnosis of CAH includes:

  • Physical exam. The doctor examines your child and evaluates symptoms. If, based on these findings, the doctor suspects CAH, the next step is to confirm the diagnosis with blood and urine tests.
  • Blood and urine tests. Tests used to diagnose CAH measure levels of hormones produced by the adrenal glands. A diagnosis can be made when there are abnormal levels of these hormones.
  • Gene testing. In older children and young adults, genetic testing may be needed to diagnose CAH.
  • Testing to determine a child's sex. In female infants who have severe ambiguous genitalia, tests can be done to analyze chromosomes to identify genetic sex. Also, pelvic ultrasound can be used to identify the presence of female reproductive structures such as the uterus and ovaries.

Source: http://www.mayoclinic.com

Complications

Complications depend on the type of congenital adrenal hyperplasia and its severity.

People with classic CAH are at risk of experiencing adrenal crisis. This is caused by severely low levels of cortisol in the blood, resulting in diarrhea, vomiting, dehydration, low blood sugar levels and shock. It's a life-threatening medical emergency that requires immediate treatment. Impaired production of aldosterone may occur as well, leading to dehydration with low sodium and high potassium levels. Adrenal crisis does not occur in the nonclassic form of CAH.

In classic and nonclassic CAH, males and females may eventually experience fertility problems.

Source: http://www.mayoclinic.com

Prevention

There is no known way to prevent congenital adrenal hyperplasia. Your doctors may recommend genetic counseling if you're thinking of starting a family and you're at risk of having a child with CAH.

Source: http://www.mayoclinic.com

Coping and support

Early and steady support from family and health care professionals can help your child grow up to have normal self-esteem and a satisfying social life. These approaches may help:

  • Include psychological counseling in your child's treatment plan as needed
  • Seek help from a mental health professional if you're having trouble coping and to help you develop healthy parenting strategies

Source: http://www.mayoclinic.com

Risk factors

Factors that increase the risk of having congenital adrenal hyperplasia include:

  • Parents who both have CAH or are both carriers of the genetic defect for the disorder
  • People in certain ethnic groups, particularly Ashkenazi Jews, but also Hispanics, Italians, Yugoslavians and Yupik Inuits

Source: http://www.mayoclinic.com

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