HSD3B2
hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 2
Gene summary
A protein-coding gene on chromosome 1 (steroid hormone synthesis). The protein encoded by this gene is a bifunctional enzyme that catalyzes the oxidative conversion of delta(5)-ene-3-beta-hydroxy steroid, and the oxidative conversion of ketosteroids. It plays a crucial role in the biosynthesis of all classes of hormonal steroids.
Source: NCBI Gene, accessed 2026-10-07.
Protein reference (UniProt)
- Protein
3 beta-hydroxysteroid dehydrogenase/Delta 5-->4-isomerase type 2
- Function
3-beta-HSD is a bifunctional enzyme, that catalyzes the oxidative conversion of Delta(5)-ene-3-beta-hydroxy steroid, and the oxidative conversion of ketosteroids. The 3-beta-HSD enzymatic system plays a crucial role in the biosynthesis of all classes of hormonal steroids.
- Pathway
Lipid metabolism; steroid biosynthesis.
- Subcellular location
Endoplasmic reticulum membrane; Mitochondrion membrane.
- Tissue specificity
Expressed in adrenal gland, testis and ovary.
- Associated conditions
Adrenal hyperplasia 2 (AH2).
Source: UniProtKB/Swiss-Prot P26439, release 2026_03, licensed CC BY 4.0. This is the protein’s normal biology, not evidence about post-drug syndromes; associated conditions are inherited disorders of the gene, not PFS, PSSD or PRSD.
Why its pathway is in the library
Steroid-synthesis enzymes sit directly on the pathways perturbed by 5-alpha-reductase inhibitors and SSRIs; inherited variation here is a candidate susceptibility factor for persistent post-drug phenotypes.
Written for the whole steroid synthesis family, not for HSD3B2 specifically.
Narrative library record
Function
The adrenal/gonadal isoform of 3-beta-HSD, predominantly expressed in adrenals, ovaries, and testes; catalyzes the same essential delta-5-to-delta-4 steroid conversion. Deficiency causes a rare congenital adrenal hyperplasia.
Corpus relevance
Background-pathway gene completing the steroidogenic map alongside HSD3B1; adrenal/gonadal expression places it at the source of the androgen and neurosteroid precursors whose downstream handling is disputed in the corpus. Not directly implicated in PFS/PSSD findings.
Mentioned in 6 corpus records
- Gene record
Steroid-hormone-activated transcription factor (nuclear receptor subfamily 3, group C, member 4). On binding testosterone or DHT it sheds accessory proteins, moves to the nucleus, dimerizes, and switches on androgen-responsive genes. Its N-terminal domain…
AKR1C2ARCYP17A1HSD3B2SRD5A2GENE-ARPFSCore corpus - Gene record
Bifunctional enzyme oxidizing delta-5-3-beta-hydroxysteroids and isomerizing them to delta-4-ketosteroids - an essential step in making all classes of active steroid hormones. HSD3B1 is expressed in placenta and peripheral tissues (critical for placental…
AKR1C1CYP17A1HSD3B1HSD3B2SRD5A1GENE-HSD3B1PFSPSSDCore corpus - Gene record
Dual-function P450 enzyme with 17-alpha-hydroxylase and 17,20-lyase activities - the key branch point of steroidogenesis that diverts pregnenolone/progesterone toward glucocorticoids versus DHEA and androstenedione (androgen precursors). Expressed in…
ARCYP17A1CYP19A1HSD3B2SRD5A1GENE-CYP17A1PFSPSSDCore corpus - Gene record
Aromatase - the P450 enzyme catalyzing the final steps of estrogen biosynthesis, converting androgens (testosterone, androstenedione) to estrogens (estradiol, estrone). Tissue-specific promoters drive expression in placenta, gonads, adipose, and brain…
AKR1C3ARCYP17A1CYP19A1HSD3B2GENE-CYP19A1PFSPSSDCore corpus - Gene recordPowers’ theory
Adrenal endoplasmic-reticulum P450 (steroid 21-hydroxylase) required for cortisol and aldosterone synthesis, converting progesterone and 17-hydroxyprogesterone toward their 21-hydroxylated products; mutations are the cause of congenital adrenal hyperplasia.
CYP11A1CYP17A1CYP21A2CYP21A2PHSD3B2GENE-CYP21A2PFSCore corpus - Gene recordPowers’ theory
Mitochondrial P450 (P450scc, cholesterol side-chain cleavage enzyme) catalyzing the first, rate-limiting step of steroidogenesis - three sequential reactions converting cholesterol to pregnenolone; severe loss disrupts all adrenal and gonadal steroid…
CYP11A1CYP17A1CYP21A2HSD3B2GENE-CYP11A1PFSCore corpus
Also in steroid hormone synthesis
All 38 genes- SRD5A2
steroid 5 alpha-reductase 2
chr 2· Steroid synthesis· 19 records - SRD5A1Powers
steroid 5 alpha-reductase 1
chr 5· Steroid synthesis· 17 records - AKR1C2Powers
aldo-keto reductase family 1 member C2
chr 10· Steroid synthesis· 12 records - AKR1C3Powers
aldo-keto reductase family 1 member C3
chr 10· Steroid synthesis· 9 records - CYP17A1
cytochrome P450 family 17 subfamily A member 1
chr 10· Steroid synthesis· 9 records - AKR1C4Powers
aldo-keto reductase family 1 member C4
chr 10· Steroid synthesis· 8 records - AKR1C1Powers
aldo-keto reductase family 1 member C1
chr 10· Steroid synthesis· 7 records - SRD5A3
steroid 5 alpha-reductase 3
chr 4· Steroid synthesis· 6 records
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