Congenital adrenal hyperplasia (CAH) is an inherited, autosomal recessive disorder that affects the adrenal glands. Individuals with CAH lack one or more of the enzymes the adrenal glands need to produce hormones. Individuals with CAH generally have lower levels of gluco- and mineralocorticoids and higher levels of androgens.
In 95% of CAH cases, the enzyme deficiency is 21-hydroxylase and may be referred to as 21-hydroxylase deficiency. The main function of 21-hydroxylase is to convert cholesterol to aldosterone and cortisol.
There are two forms of CAH: classical and nonclassical.
- Classical CAH is more life-threatening. The signs and symptoms of classical CAH appear more drastically in females than in males, because of genital ambiguity as a result of this condition. Signs and symptoms of classic CAH include anything related to the lack of cortisol and aldosterone. These signs may include low blood pressure, low blood sugar, fatigue, dehydration, electrolyte imbalances, excess male sex hormones (which can cause early onset of puberty), short height, and genital abnormalities.
- Nonclassical CAH is a milder version of CAH and can be asymptomatic and non-life-threatening. Nonclassical CAH is not often detected on routine infant blood screening and becomes evident late in childhood or early adulthood. Signs and symptoms in females often include irregular menstrual cycles or amenorrhea and masculine features (excess body and facial hair). In both sexes, puberty happens much earlier with rapid growth during childhood, however, growth may be stunted earlier than normal and non-classical CAH patients are often smaller than average.
