17-Hydroxylase Deficiency Syndrome Workup

Updated: Mar 16, 2021
  • Author: J Paul Frindik, MD, FACE; Chief Editor: Stephen Kemp, MD, PhD  more...
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Workup

Laboratory Studies

Male and female patients have no biochemical differences.

All steroids requiring 17-hydroxylase (17-OH) activity for their production are found in very low concentrations. 17-Hydroxypregnenolone (17-OH Preg), 17-hydroxyprogesterone (17-OH Prog; see 17-Hydroxyprogesterone, Serum and 17-Hydroxyprogesterone, Urine), 11-deoxycortisol (compound S), cortisol, dehydroepiandrosterone (DHEA), androstenedione, and testosterone are all decreased or absent. The urinary metabolites 17-hydroxylase corticosteroid and 17-ketosteroid also are decreased or absent.

Serum estrogens and urinary estrogens are low.

Pregnenolone and progesterone levels are somewhat elevated; diagnosis is confirmed by markedly elevated levels of 11-deoxycorticosterone (11-DOC) and corticosterone.

Aldosterone and plasma renin concentrations are usually low. DOC-mediated mineralocorticoid activity causes sodium retention and plasma volume expansion, with subsequent suppressed renin and aldosterone levels in most untreated patients.

Within the pituitary, adrenocorticotropic hormone (ACTH) levels are elevated due to lack of cortisol secretion. The gonadotropins, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) are elevated secondary to deficient sex steroid production by the gonads.

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Other Tests

17-Hydroxylase deficiency is inherited as an autosomal recessive trait similar to other forms of congenital adrenal hyperplasia (CAH). However, 17-hydroxylase is not linked to the human leukocyte antigen (HLA) system. Detection of heterozygote carriers is difficult and requires biochemical rather than genetic criteria.

Unstimulated levels of 11-deoxycorticosterone (11-DOC) and corticosterone may be somewhat elevated in heterozygotes, and these individuals may have an exaggerated response to ACTH stimulation.

Prenatal diagnosis of an affected infant is possible by measuring amniotic fluid concentrations of adrenal steroids or maternal urine steroid metabolite excretion. [33]

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