SRD5A3

Chr 4AR

steroid 5 alpha-reductase 3

Also known as: CDG1P, CDG1Q, KRIZI, S5AR, S5AR 3, SRD5A2L, SRD5A2L1

NCBI Gene: 79644 ENSG00000128039 UniProt: Q9H8P0 OMIM: 611715

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.

OMIM ResearchSummary from RefSeq, OMIM, UniProt

The protein encoded by this gene belongs to the steroid 5-alpha reductase family, and polyprenol reductase subfamily. It is involved in the production of androgen 5-alpha-dihydrotestosterone (DHT) from testosterone, and maintenance of the androgen-androgen receptor activation pathway. This protein is also necessary for the conversion of polyprenol into dolichol, which is required for the synthesis of dolichol-linked monosaccharides and the oligosaccharide precursor used for N-linked glycosylation of proteins. Mutations in this gene are associated with congenital disorder of glycosylation type Iq. [provided by RefSeq, Mar 2011]

OMIM ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

Congenital disorder of glycosylation, type IqMIM #612379

Kahrizi syndromeMIM #612713

Clinical highlights

Gene-disease validity (ClinGen)

SRD5A3-congenital disorder of glycosylation · ARDefinitivesufficient evidence for diagnostic panels

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

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P/LP submissions

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P/LP missense

0.97

LOEUF

LOF

Mechanism· G2P