When it occurs it resembles the salt-wasting of severe 21-hydroxylase deficient CAH: poor weight gain and vomiting in the first weeks of life progress and culminate in life-threatening dehydration, hyponatremia, hyperkalemia, and metabolic acidosis in the first month.

[2] Because 11β-hydroxylase activity is not necessary for the production of sex steroids (androgens and estrogens), the hyperplastic adrenal cortex produces excessive amounts of DHEA, androstenedione, and especially testosterone.

In milder mutations, androgen effects in both sexes appear in mid-childhood as early pubic hair, overgrowth, and accelerated bone age.

Like the other forms of CAH, several different defective alleles for the gene have been identified, producing varying degrees of impaired 11β-hydroxylase activity.

Salt-wasting in infancy responds to intravenous saline, dextrose, and high dose hydrocortisone, but prolonged fludrocortisone replacement is usually not necessary.

Because the enzyme defect does not affect sex steroid synthesis, gonadal function at puberty and long-term fertility should be normal if adrenal androgen production is controlled.

See congenital adrenal hyperplasia for a more detailed discussion of androgen suppression and fertility potential in adolescent and adult women.