3-Beta-Hydroxysteroid Dehydrogenase Deficiency Workup

Updated: Jun 16, 2016
  • Author: J Paul Frindik, MD, FACE; Chief Editor: Stephen Kemp, MD, PhD  more...
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Workup

Laboratory Studies

No biochemical differences between male and female patients are recognized.

  • Classic 3-beta–hydroxysteroid dehydrogenase (3BHSD) deficiency

    • Plasma concentrations of pregnenolone, 17-hydroxypregnenolone, and DHEA are elevated.

    • 17-Hydroxyprogesterone levels may be increased because of conversion of 17-hydroxypregnenolone to 17-hydroxyprogesterone by peripheral type I 3-beta–hydroxysteroid dehydrogenase isoenzyme and may be detected by neonatal screening for 21-hydroxylase deficiency. [15, 16]

    • Peripheral type I 3-beta–hydroxysteroid dehydrogenase activity may also increase androstenedione levels. [15] However, in 3-beta–hydroxysteroid dehydrogenase deficiency, the plasma ratio of 17-hydroxypregnenolone to 17-hydroxyprogesterone is markedly elevated. Plasma cortisol and aldosterone levels are low in 3-beta–hydroxysteroid dehydrogenase.

    • Adrenocorticotropic hormone (ACTH) levels are elevated because of the lack of cortisol secretion, and gonadotropin follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are elevated secondary to deficient sex steroid production.

  • Late-onset or nonclassic 3-beta–hydroxysteroid dehydrogenase deficiency: Baseline (unstimulated) measurements of pregnenolone, 17-hydroxypregnenolone, and dehydroepiandrosterone (DHEA) may be unremarkable in patients with late-onset or nonclassic 3-beta–hydroxysteroid dehydrogenase deficiency. In such patients, diagnosis is based on an excessive response of 17-hydroxypregnenolone (delta 5-17Preg) and delta 5-17Preg-to-F ratios at or greater than 201 nmol/L and 487 nmol/L, respectively; this is equivalent to or greater than 36 standard deviations (SD) and 52 SD above matched control mean, respectively. [19]

  • Carriers: Carriers of type II 3-beta–hydroxysteroid dehydrogenase deficiency can have hormone profiles (both stimulated and unstimulated) within the reference range and, therefore, can only be detected by genotype studies.

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Imaging Studies

Imaging studies may reveal polycystic ovaries in older patients or enlarged adrenal glands; such findings are nonspecific and not diagnostic for any particular type of enzyme deficiency.

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Other Tests

Genotyping is not routinely required for diagnosis but may be helpful if hormone testing is inconclusive. Molecular genetic studies are indicated, as noted above, to detect carriers as well as for genetic counseling of the individual and family. [20]

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