SRD5A1

Chr 5

steroid 5 alpha-reductase 1

Also known as: S5AR 1

The protein converts testosterone to dihydrotestosterone (DHT) and metabolizes progesterone and corticosteroids, playing a central role in sexual differentiation and androgen physiology. Unlike SRD5A2 deficiency which causes well-characterized disorders of sexual development, SRD5A1 mutations have not been definitively associated with human disease. The gene appears highly tolerant to loss-of-function variation based on population genetics data.

Summary from RefSeq, UniProt, Mechanism
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2
Active trials
36
Pubs (1 yr)
106
P/LP submissions
0%
P/LP missense
1.29
LOEUF
Multiple*
Mechanism· predicted
Clinical SummarySRD5A1
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
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ClinVar Variants
106 unique Pathogenic / Likely Pathogenic· 37 VUS of 155 total submissions
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Clinical Trials
2 active or recruiting trials — potential therapeutic options may be available
Some data sources returned errors (1)

ensembl: TimeoutError: The operation was aborted due to timeout

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
1.29LOEUF
pLI 0.000
Z-score 0.84
OE 0.74 (0.451.29)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
0.59Z-score
OE missense 0.86 (0.751.00)
129 obs / 149.3 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.74 (0.451.29)
00.351.4
Missense OE0.86 (0.751.00)
00.61.4
Synonymous OE1.18
01.21.6
LoF obs/exp: 9 / 12.2Missense obs/exp: 129 / 149.3Syn Z: -1.09
DN
0.79top 25%
GOF
0.6931th %ile
LOF
0.1993th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median
GOFprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

155 submitted variants in ClinVar

Classification Summary

Pathogenic105
Likely Pathogenic1
VUS37
Likely Benign5
Benign3
105
Pathogenic
1
Likely Pathogenic
37
VUS
5
Likely Benign
3
Benign

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
0
0
105
0
105
Likely Pathogenic
0
0
1
0
1
VUS
0
35
2
0
37
Likely Benign
0
3
1
1
5
Benign
0
1
0
2
3
Total0391093151

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

SRD5A1 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Clinical Literature
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