Congenital Adrenal Hyperplasia
What Is Congenital Adrenal Hyperplasia?
Congenital Adrenal Hyperplasia (CAH) is a genetic disorder where dysfunctional enzymes affect hormone production within the adrenal glands. The adrenals are two glands located just on top of our kidneys. The vast majority of cases of CAH are caused by 21-hydroxylase deficiency, so you may hear it referred to by that name. However, there are other enzyme deficiencies that can also lead to CAH. The adrenal glands are endocrine organs responsible for producing and releasing three types of hormones:
- Cortisol, which regulates energy, blood pressure, blood sugar, and helps us recover from illnesses
- Aldosterone, which regulates the amount of sodium and potassium in our bloodstream
- Androgens, which are responsible for the development of secondary sexual characteristics (adrenarche) in both males and females.
All three of these adrenal hormones are necessary for normal body functioning in both males and females. In patients with Congenital Adrenal Hyperplasia, the adrenal glands typically produce too little cortisol and aldosterone, while producing too much of the androgen hormones. Excess levels of androgens can cause atypical genitalia, growth abnormalities, early puberty, and problems with fertility.
There are two major types of congenital adrenal hyperplasia: classic CAH and nonclassic CAH. Classic CAH is the rarer of the two forms and is usually detected in infancy. Approximately 2/3 of patients with classic CAH have the salt-losing form, while the remaining 1/3 have the simple-virilizing form. Nonclassic CAH is milder and more common than classic CAH. Nonclassic CAH is often not diagnosed until childhood or early adulthood.
What Are The Causes Of Congenital Adrenal Hyperplasia?
Over 95% of cases of CAH are caused by 21-hydroxylase deficiency, which is a genetic disorder (autosomal recessive). There are other much rarer enzyme deficiencies that can also cause CAH.
What Are The Signs And Symptoms Of Congenital Adrenal Hyperplasia?
The signs and symptoms of classic CAH vary between the salt-losing form and the virilizing form. In girls, both forms cause atypical genitalia in the neonatal period. In boys, the salt-losing form presents as a salt-losing adrenal crisis characterized by hyponatremia, hyperkalemia, and failure to thrive; whereas the virilizing form presents with signs of puberty in toddlers.
Non-classic CAH may present as excessive hair growth and menstrual irregularity in young women, early onset of puberty in school-age children, or can sometimes be asymptomatic.
What Are The Risk Factors Of CAH?
Factors that increase the risk of having CAH are having parents who both have the disorder or who are both carriers of the genetic defect for this disorder. Additionally, certain ethnic heritages, such as Ashkenazi Jew, Hispanic, Italian, Yugoslav, and Yupik Inuit are at increased risk of having the disorder.
How Is Congenital Adrenal Hyperplasia (CAH) Diagnosed?
CAH may be diagnosed before a baby is born, during childhood or later in life.
It may diagnosed in the prenatal period by amniocentesis, chorionic villus sampling, or by maternal blood test. All infants born in the United States are screened for common forms of classical Congenital Adrenal Hyperplasia shortly after birth. If your child is diagnosed with Congenital Adrenal Hyperplasia, additional tests including blood tests and imaging tests, such as X-rays or ultrasounds, are often done. Ultimately, genetic testing is used to confirm the diagnosis.
In older children and young adults, CAH may be detected based on physical exam findings, blood and urine tests, and genetic testing.
What Are The Possible Treatments For Congenital Adrenal Hyperplasia?
CAH is a condition that requires long-term follow-up and monitoring. The goals of treatment are preventing excessive androgen production and replacing deficient hormones. The treatment may involve life-long cortisol with or without aldosterone replacement therapy, in order to make up for what the adrenal glands are unable to produce themselves. In some cases, surgery is required.
Are There Preventative Steps Or Measures To Avoid Congenital Adrenal Hyperplasia?
No, it is a genetic disorder.
What Are The Risks If Congenital Adrenal Hyperplasia Is Left Untreated?
Patients who have classic CAH are at risk for adrenal crisis because they have very low levels of cortisol in the blood. This can cause diarrhea, vomiting, dehydration, hypoglycemia, and shock. Adrenal crisis is a life-threatening medical emergency that requires immediate treatment. Levels of a hormone called aldosterone may also be low, which leads to dehydration, low sodium levels, and high potassium levels. Adrenal crisis does not occur in the nonclassic form of CAH.
Both male and female patients either classic or nonclassic CAH may have problems with fertility.
Are There Other Related Conditions To Congenital Adrenal Hyperplasia?
As above, classic CAH can cause adrenal crisis and both classic and nonclassic CAH can cause fertility problems.
Congenital Adrenal Hyperplasia About Condition (CAH)
- It is a genetic disorder
- Usually caused by 21-hydroxylase deficiency
- There is no cure, but with proper management, patients with CAH may minimize complications of the disease and maintain a good quality of life