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SRD5A3 gene

steroid 5 alpha-reductase 3

Normal Function

The SRD5A3 gene provides instructions for making an enzyme called steroid 5-alpha reductase 3. This enzyme performs a chemical reaction that converts a compound called polyprenol into another compound called dolichol. Subsequently, another enzyme converts dolichol to dolichol phosphate. The production of dolichol phosphate is critical for a process called glycosylation, by which small chains of sugar molecules (oligosaccharides) are attached to proteins. Glycosylation changes proteins in ways that are important for their functions.

Dolichol phosphate is integral for the formation of the sugar chains that are attached to proteins during glycosylation. Individual sugars are added to dolichol phosphate to build the oligosaccharide chain. Once the chain is formed, it is transferred from dolichol phosphate to a specific site on the protein that needs to be glycosylated.

Health Conditions Related to Genetic Changes

SRD5A3-congenital disorder of glycosylation

More than 15 variants (also known as mutations) in the SRD5A3 gene have been found to cause SRD5A3-congenital disorder of glycosylation (SRD5A3-CDG). This condition primarily causes neurological and vision problems but can also cause other signs and symptoms.

Variants in the SRD5A3 gene generally lead to the production of abnormally small steroid 5 alpha-reductase 3 enzyme. This abnormal enzyme  either has no activity or is quickly broken down. The lack of steroid 5 alpha-reductase 3 enzyme activity impairs the formation of dolichol, which also reduces dolichol phosphate production. As a result, glycosylation cannot proceed normally. The signs and symptoms of SRD5A3-CDG are likely due to impaired glycosylation of proteins that are needed for the normal function of various organs and tissues.

More About This Health Condition

Other Names for This Gene

  • FLJ13352
  • SRD5A2L
  • SRD5A2L1

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Ben Ayed I, Ouarda W, Frikha F, Kammoun F, Souissi A, Ben Said M, Bouzid A, Elloumi I, Hamdani TM, Gharbi N, Baklouti N, Guirat M, Mejdoub F, Kharrat N, Boujelbene I, Abdelhedi F, Belguith N, Keskes L, Gibriel AA, Kamoun H, Triki C, Alimi AM, Masmoudi S. SRD5A3-CDG: 3D structure modeling, clinical spectrum, and computer-based dysmorphic facial recognition. Am J Med Genet A. 2021 Apr;185(4):1081-1090. doi: 10.1002/ajmg.a.62065. Epub 2021 Jan 6. Citation on PubMed
  • Jaeken J, Lefeber DJ, Matthijs G. SRD5A3 defective congenital disorder of glycosylation: clinical utility gene card. Eur J Hum Genet. 2020 Sep;28(9):1297-1300. doi: 10.1038/s41431-020-0647-3. Epub 2020 May 18. No abstract available. Citation on PubMed
  • Kousal B, Honzik T, Hansikova H, Ondruskova N, Cechova A, Tesarova M, Stranecky V, Meliska M, Michaelides M, Liskova P. Review of SRD5A3 Disease-Causing Sequence Variants and Ocular Findings in Steroid 5alpha-Reductase Type 3 Congenital Disorder of Glycosylation, and a Detailed New Case. Folia Biol (Praha). 2019;65(3):134-141. Citation on PubMed
  • Morava E, Wevers RA, Cantagrel V, Hoefsloot LH, Al-Gazali L, Schoots J, van Rooij A, Huijben K, van Ravenswaaij-Arts CM, Jongmans MC, Sykut-Cegielska J, Hoffmann GF, Bluemel P, Adamowicz M, van Reeuwijk J, Ng BG, Bergman JE, van Bokhoven H, Korner C, Babovic-Vuksanovic D, Willemsen MA, Gleeson JG, Lehle L, de Brouwer AP, Lefeber DJ. A novel cerebello-ocular syndrome with abnormal glycosylation due to abnormalities in dolichol metabolism. Brain. 2010 Nov;133(11):3210-20. doi: 10.1093/brain/awq261. Epub 2010 Sep 17. Citation on PubMed
  • Taylor RL, Arno G, Poulter JA, Khan KN, Morarji J, Hull S, Pontikos N, Rueda Martin A, Smith KR, Ali M, Toomes C, McKibbin M, Clayton-Smith J, Grunewald S, Michaelides M, Moore AT, Hardcastle AJ, Inglehearn CF, Webster AR, Black GC; UK Inherited Retinal Disease Consortium and the 100,000 Genomes Project. Association of Steroid 5alpha-Reductase Type 3 Congenital Disorder of Glycosylation With Early-Onset Retinal Dystrophy. JAMA Ophthalmol. 2017 Apr 1;135(4):339-347. doi: 10.1001/jamaophthalmol.2017.0046. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.