Congenital adrenal hyperplasia

Alternative names:

adrenogenital syndrome

Definition:

A disorder present at birth characterized by a deficiency in the hormones cortisol and aldosterone (see the aldosterone test), and an over production of androgen (male sex hormones).

Causes, incidence, and risk factors:

The different types of adrenogenital syndrome are inherited as autosomal recessive gene defects. This defect results in the lack of an enzyme needed by the adrenal gland to make cortisol. In response to deficient cortisol, the pituitary gland secretes a hormone (ACTH -- see the ACTH test) that stimulates the adrenal gland, causing the overproduction of androgen (male) hormones but without causing a desired increase in cortisol.

The condition affects both females and males. In a female newborn with this disorder, the clitoris is enlarged with the urethral opening at the base (ambiguous genitalia, often appearing more male- like than female). The internal structures of the reproductive tract (ovaries, uterus and Fallopian tubes) are normal. As she grows older, masculinization of some features takes place, such as deepening of the voice, the appearance of facial hair, and failure to menstruate at puberty. In a male newborn no obvious abnormality is present, but long before puberty normally occurs, the child becomes increasingly muscular, the penis enlarges, pubic hair appears, and the voice deepens. Affected males may appear to enter puberty as early as 2-3 years of age. At puberty, the testes are small.

Some forms of congenital adrenal hyperplasia are more severe and cause adrenal crisis in the newborn due to salt wasting. In the salt-losing form of adrenogenital syndrome, newborn infants develop symptoms shortly after birth. These include vomiting, dehydration, electrolyte changes, and cardiac arrhythmias. Untreated, this condition can lead to death within 9 to 14 days after the infant's birth.