What Are the Causes of Congenital Adrenal Hyperplasia (CAH)?
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Congenital Adrenal Hyperplasia - Types, Causes, Symptoms, Diagnosis, and Treatment

Published on Aug 25, 2022   -  5 min read


Congenital adrenal hyperplasia is a genetic disorder that affects the adrenal glands since birth. Read the article to know more about the condition.


Adrenal glands are two walnut-shaped glands located on top of the kidneys. Aldosterone, cortisol, testosterone, adrenaline, and noradrenaline are the essential hormones produced by the adrenals that regulate different body functions. Congenital adrenal hyperplasia (CAH) is a genetic disorder in which a mutation leads to a shortage of an enzyme called 21-hydroxylase required to produce adrenal hormones. In most patients, the lack of the enzyme leads to the overproduction of some hormones like testosterone.

What Are the Types of Congenital Adrenal Hyperplasia?

Two types of CAH include:

  1. Classic CAH: Classic CAH is a severe form of the disorder. It is diagnosed in infancy or early childhood. In one form of CAH, the adrenal glands do not produce enough amounts of aldosterone and cortisol. The lack of aldosterone leads to the loss of sodium, causing an electrolyte imbalance in the body. This form of CAH is referred to as “salt-wasting” CAH. Classic CAH is a life-threatening condition that can lead to shock and death if left untreated.
  2. Nonclassic CAH: Nonclassic CAH is a less severe, more common form diagnosed in late childhood or adulthood. The symptoms of “salt-wasting” CAH are absent in the nonclassic type, and there is some 21-hydroxylase activity left in the body. Symptoms include early puberty, pubic hair growth, and irregular menstrual cycles in females.

What Are the Causes of Congenital Adrenal Hyperplasia?

The primary cause of CAH is the deficiency of the enzyme 21-hydroxylase, which is needed to produce adrenal hormones. Patients with CAH inherit the defective gene from their parents, who may be affected by CAH or may be carriers of the gene.

What Are the Symptoms of Congenital Adrenal Hyperplasia?

The symptoms of CAH depend upon various factors like age, gender, and the type of CAH.

Symptoms of classic CAH occur due to the deficiency of the 21-hydroxylase enzyme. Classic CAH is further subcategorized into two types:

  1. Salt-wasting type is a more severe form of the disease, with deficiency of aldosterone leading to an imbalance in the water and electrolyte levels.

  2. Non-salt-wasting (simple virilizing) type is a more common form of the disease that shows some enzyme activity.

Salt wasting type of CAH presents the following symptoms that include:

Symptoms that occur in salt-wasting CAH due to increased levels of androgens include:

  • Abnormally enlarged external genitalia in female infants.

  • Early signs of puberty like oily skin, pubic and armpit hair, and voice changes.

  • Irregular menstrual cycles.

  • Rapid growth.

  • Benign (harmless) testicular tumors.

  • Infertility.

Symptoms of non-salt-wasting (simple virilizing) type occur due to high levels of androgens that include:

  • Unusual external genitalia in female infants.

  • Early development of male characteristics like voice changes and bulky muscles in boys or females.

Symptoms of nonclassic CAH are less severe and present as:

  • Early signs of puberty like excess body hair and oily skin.

  • Fast growth in childhood.

  • Irregular menstrual cycle.

  • Baldness.

  • Decreased fertility.

  • Early pubertal signs in boys like an increase in the size of the penis and early pubic hair.

What Are the Complications of Congenital Adrenal Hyperplasia?

People affected with classic CAH are at a high risk of developing adrenal crisis due to the low cortisol levels. An adrenal crisis is a medical emergency that requires immediate treatment. It may cause severe symptoms like vomiting, diarrhea, dehydration, low blood glucose levels, and shock.

How to Diagnose Congenital Adrenal Hyperplasia?

Screening is done in newborn babies to detect the deficiency of the 21-hydroxylase enzyme before they leave the hospital. Also, abnormal external genitalia in female infants can help diagnose classic CAH. Male and female infants who have severe illness due to low levels of cortisol and aldosterone can be identified as cases of classic CAH. Diagnosis of nonclassic CAH is based on the physical examination, signs, and symptoms. Nonclassic CAH shows early signs of puberty. Specific tests are conducted in fetuses and newborn children to diagnose CAH, including:

Prenatal Tests:

Prenatal tests that are done on fetuses to diagnose CAH include:

  1. Amniocentesis is a procedure in which the amniotic fluid collected from the womb is examined.

  2. Chorionic villus sampling involves examining the cells withdrawn from the placenta.

Tests are done in older children and teenagers that include:

  • Physical Examination: Signs of early puberty detected on physical examination are confirmed by blood and urine tests.

  • Blood and Urine Tests: Abnormal hormonal levels due to improper functioning of adrenals are detected in the blood and urine tests.

  • Genetic Testing: In older children, genetic testing helps detect the defective gene.

  • Determination of the Child’s Sex: In cases where the infant has abnormal genitalia, genetic testing to determine the sex of the baby is done.

  • Ultrasound Scan: An ultrasound scan of the abdomen helps identify the presence of female organs like the uterus and ovaries.

How Is Congenital Adrenal Hyperplasia Treated?

The treatment options for CAH include medications and reconstructive surgery.

Medications: Treatment with medicines aims to replace deficient hormones and manage excess androgens. Medicines that are prescribed include the following:

  • Mineralocorticoids that replace aldosterone helps to retain sodium and remove potassium.
  • Corticosteroids are used to replace cortisol.
  • Salt supplements help maintain the required salt levels in the body.

The patients are advised to take medicines daily for the rest of their lives. In cases of stress like trauma or surgery, the doses of drugs might be increased.

Reconstructive Surgery: Reconstructive surgery is planned for female patients who exhibit ambiguous external genitalia. The surgery is scheduled when the baby is between 2 to 6 months. Surgery involves reducing the size of the clitoris and reconstruction of the vaginal opening. As the child grows, she may also need further cosmetic surgeries.


Health care professionals and parents need to work together to help the child cope. The psychological and mental well-being of the child that enables them to socialize better should be taken care of by psychologists and counselors. Parents can also seek help to understand parenting strategies for children having CAH. Early diagnosis and treatment can improve the quality of life of the patient. Women with genetic risk who wish to plan pregnancy need to consult a genetic counselor to understand the situation better.

Frequently Asked Questions


How Do You Diagnose CAH?

Diagnosis of congenital adrenal hyperplasia (CAH) in children and young adults include:
 - Physical examination.
 - Blood and urine tests.
 - Genetic testing.


Is Congenital Adrenal Hyperplasia Curable?

Although there is no cure for CAH, individuals can lead a normal treatment with proper supportive care.


Can Congenital Adrenal Hyperplasia Be Diagnosed in Adults?

Normally, children, teenagers, and adults are all diagnosed with nonclassic CAH. The symptoms include early onset of puberty, including acne, and excess facial or body hair in females.


What Is the Life Expectancy of Someone With Congenital Adrenal Hyperplasia?

The mortality rate for individuals with CAH is a mean age of death was 41.2 plus or minus 26.9 years.


Can People With Congenital Adrenal Hyperplasia Have Kids?

Children with CAH can develop like other children, and in adulthood most will be able to have their own kids.


Can I Get Pregnant if I Have Congenital Adrenal Hyperplasia?

Individuals with CAH have a lower pregnancy rate compared to normal women. Also, studies have shown that individuals with either 21-hydroxylase or 11-beta hydroxylase deficiency face challenges with fertility.


Is Hyperplasia Genetic?

CAH is a genetic disorder, which means it is inherited from the parents and is present at birth.


Can Congenital Adrenal Hyperplasia Cause Fatigue?

Yes, almost 41 % of the time, CAH causes fatigue in the affected individuals.


Can Congenital Adrenal Hyperplasia Go Away?

Even though there is no cure for CAH yet, prompt treatment provides makes it possible to lead a normal life.


Can You Live a Normal Life With CAH?

Even though there is no cure for CAH yet, prompt treatment and diagnosis offers the individual the possibility of leading a normal life.


What Is the Most Common Type of CAH?

The most common type of congenital adrenal hyperplasia is due to mutations or deletions of the CYP21A resulting in 21 hydroxylase deficiency.


How Do You Test for Congenital Adrenal Hyperplasia?

Diagnosis for CAH in children and adults includes physical examination and the diagnosis is confirmed with blood and urine tests.


What Is CAH in Newborn Screening?

Non-classical type of CAH is not detected through newborn screening of infants.


How Common Is Non-classic CAH?

Classical CAH, the most common form of the disease, affects as many as 1 in every 10000 to 15000.


Can a Baby Be Born Without Adrenal Glands?

Yes, a baby can be born without adrenal glands. An absent adrenal gland is a rare condition where the adrenal gland is absent at birth.

Last reviewed at:
25 Aug 2022  -  5 min read




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