A 4-year-old male visits his pediatrician for a check-up. His height corresponds to the 99th percentile for his age, and pubic hair is present upon physical examination. Serum renin and potassium levels are high, as is 17-hydroxyprogesterone. Which of the following is likely deficient in this patient?
21-hydroxylase deficiency is the most common form of adrenogenital syndrome (congenital adrenal hyperplasia) and presents with precocious puberty, virilization, and accelerated linear growth. Hypotension and hyperkalemia may also be present due to a decrease in mineralocorticoids, with corresponding elevation in plasma renin levels.
21-hydroxylase deficiency is an autosomal recessive disorder where increased 17-hydroxyprogesterone and androgens occur as corticosteroid precursors are shunted to the androgenic synthesis pathways. Synthesis of cortisol and aldosterone are markedly decreased, which can result in hyperkalemia and hypotension and a compensatory increase in renin. Afflicted females present with pseudohermaphrodism due to virilization from elevated androgen production. Treatment includes exogenous glucocorticoids and mineralocorticoids.
Illustration A diagrams steroidogenesis. Note the role of 21-hydroxylase (21a-hydroxylase in image) in the production of aldosterone and cortisol. Also note that 11ß-hydroxylase deficiency allows for production of 11-deoxycorticosterone, which acts as a mineralocorticoid when secreted in excess. Plasma renin and potassium levels are low in this disorder.