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SRD5A3 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SRD5A3 gene

The SRD5A3 gene provides instructions for an enzyme critical to glycosylation, a process that modifies proteins for proper function in the body.

Normal Function

The SRD5A3 gene provides instructions for making an enzyme called steroid 5-alpha reductase 3. This enzyme converts a compound called polyprenol into dolichol, which is then converted to dolichol phosphate. Dolichol phosphate is critical for glycosylation, a process where sugar chains (oligosaccharides) are attached to proteins. This modification is essential for the proper function of many proteins throughout the body.

Health Conditions Related to Genetic Changes

SRD5A3-congenital disorder of glycosylation

More than 15 variants in the SRD5A3 gene have been found to cause SRD5A3-congenital disorder of glycosylation (SRD5A3-CDG). This condition primarily causes neurological and vision problems.

Variants in this gene generally lead to the production of an abnormally small enzyme that either has no activity or is quickly broken down. The lack of enzyme activity impairs the formation of dolichol and dolichol phosphate, which prevents normal glycosylation. The resulting signs and symptoms are due to the impaired glycosylation of proteins required for the normal function of various organs and tissues.

Frequently Asked Questions

Key clues include developmental delay, seizures, abnormal eye movements or vision loss, and failure to thrive within the first year of life, especially when multiple organ systems are involved.
No cure exists, but supportive care can help: seizure control with antiepileptics, vision support (low‑vision aids), physical and occupational therapy, and nutritional supplementation (e.g., mannose‑6‑phosphate) may mitigate some symptoms. Early multidisciplinary intervention is essential.
blood draw (or sometimes saliva) is used to extract DNA, which is then analyzed by targeted gene panel or whole‑exome sequencing to identify pathogenic SRD5A3 mutations.
Carriers (typically parents) are usually asymptomatic because one functional copy of the gene is sufficient. However, they have a 50 % chance of passing the mutation to each child, so genetic counseling is recommended before family planning.
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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