SRD5A3
Chr 4ARsteroid 5 alpha-reductase 3
Also known as: CDG1P, CDG1Q, KRIZI, S5AR, S5AR 3, SRD5A2L, SRD5A2L1
The protein functions as a polyprenol reductase that converts polyprenol to dolichol in the early steps of protein N-linked glycosylation and also converts testosterone to dihydrotestosterone. Biallelic mutations cause congenital disorder of glycosylation type Iq and Kahrizi syndrome, both presenting with intellectual disability and developmental delays along with multisystem involvement including cerebellar ataxia and ophthalmologic abnormalities. This follows autosomal recessive inheritance.
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Typical tolerance to LoF variation
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
SRD5A3 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools