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HSD3B2 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

HSD3B2 gene

The HSD3B2 gene is responsible for producing the 3-beta-hydroxysteroid dehydrogenase enzyme, which is critical for the synthesis of essential hormones in the adrenal glands and gonads.

Normal Function

The HSD3B2 gene provides instructions for making the 3-beta-hydroxysteroid dehydrogenase (3β-HSD) enzyme. This enzyme is found in the gonads (ovaries in females and testes in males) and the adrenal glands located on top of the kidneys.

Within these tissues, the 3β-HSD enzyme is necessary for the production of several hormones:

  • Cortisol: Maintains energy and blood sugar levels, protects against stress, and suppresses inflammation.
  • Aldosterone: Regulates salt retention in the kidneys, which influences fluid levels and blood pressure.
  • Androgens and Estrogen: Essential for normal sexual development and reproduction.

Health Conditions Related to Genetic Changes

3-beta-hydroxysteroid dehydrogenase deficiency

At least 37 mutations in the HSD3B2 gene have been identified as causes of 3β-HSD deficiency. These mutations typically reduce the activity of the enzyme, interfering with hormone production and leading to abnormalities in sexual development and maturation.

  • Non-classic forms: Mutations that allow for the production of some functional enzyme at reduced levels result in less severe, non-salt-wasting forms of the condition.
  • Classic forms: Mutations that result in an abnormally short, completely nonfunctional enzyme cause the more severe, salt-wasting form of the condition.

Other Names for This Gene

  • 3 beta-HSD type II
  • 3 beta-hydroxysteroid dehydrogenase 2
  • 3 beta-hydroxysteroid dehydrogenase type II, delta 5-delta 4-isomerase type II, 3 beta-HSD type II
  • 3 beta-ol dehydrogenase
  • 3-beta-hydroxy-5-ene steroid dehydrogenase
  • 3-beta-hydroxy-delta(5)-steroid dehydrogenase
  • 3BHS2_HUMAN
  • delta 5-delta 4-isomerase type II
  • HSD3B
  • HSDB

Frequently Asked Questions

In newborns, the classic, severe form often presents as a salt-wasting crisis, with symptoms like poor feeding, vomiting, dehydration, low blood pressure, and lethargy, which can be life-threatening. Affected females may have ambiguous genitalia, while males might have underdeveloped external genitalia. Less severe, non-classic forms may lead to milder symptoms later in childhood, such as early puberty, acne, or irregular menstruation in females, and mild genital abnormalities in males.
Diagnosis typically involves blood tests to measure hormone levels, such as elevated precursors like 17-hydroxypregnenolone and dehydroepiandrosterone (DHEA), and low levels of cortisol and aldosterone. Genetic testing of the HSD3B2 gene confirms the diagnosis. Treatment involves lifelong hormone replacement therapy, primarily with glucocorticoids (like hydrocortisone) to replace cortisol and mineralocorticoids (like fludrocortisone) to replace aldosterone and manage salt balance. Regular monitoring of hormone levels is crucial.
Yes, 3-beta-hydroxysteroid dehydrogenase deficiency is an autosomal recessive condition. This means a child must inherit two mutated copies of the HSD3B2 gene, one from each parent, to develop the condition. Parents who each carry one copy of the mutated gene are typically unaffected but have a 25% chance with each pregnancy of having a child with the deficiency. Genetic counseling is recommended for affected families.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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