5-Alpha-Reductase Deficiency
(also: 5-ARD, PPSH, Pseudovaginal Perineoscrotal Hypospadias, Steroid 5-Alpha-Reductase Deficiency)
Table of Contents
General Information
5-ARD is an intersex variation that affects sexual development before birth and during puberty. Those who have this variation have XY chromosomes. Most people with 5-ARD have testes and produce typical levels of testosterone. Some will have a micropenis that may have proximal hypospadias. Some will have a vulva and be assigned female (possibly without being identified as intersex). Some people will be born with ambiguous genitalia. Most people with this intersex variation are infertile.
Someone with this disorder does not have the enzyme responsible for converting testosterone into the more powerful anti-androgen known as dihydrotestosterone (DHT). During puberty, someone with 5-ARD will typically develop some features assiciated with a typical testosterone-based puberty, such as increased muscle mass, depth of voice, hair growth, and possible genital growth.
This is a rare, genetically inherited condition.
External Links
The resources below have been provided for education, information sourcing, and entertainment purposes. The views expressed in these videos, websites, etc, do not inherently reflect those of The Transgender Dictionary. These resources are not sponsored, nor endorsed.
- Health Jade: 5 alpha reductase deficiency (https://healthjade.com/5-alpha-reductase-deficiency/)
- Intersex Wiki - 5 Alpha Reductase Deficiency (https://intersex.wiki/wiki/5-Alpha_reductase_deficiency)
- Lurie Children's Hospital: 5-alpha Reductase Deficiency (https://www.luriechildrens.org/en/specialties-conditions/5-alpha-reductase-deficiency/)
- MedlinePlus: 5-alpha reductase deficiency (https://medlineplus.gov/genetics/condition/5-alpha-reductase-deficiency/)
- National Institute of Health: GARD: 46,XY disorder of sex development due to 5-alpha-reductase 2 deficiency (https://rarediseases.info.nih.gov/diseases/5680/index)
- National Library of Medicine: Genetic Testing Registry: 3-Oxo-5 alpha-steroid delta 4-dehydrogenase deficiency (https://www.ncbi.nlm.nih.gov/gtr/conditions/C0268297/)
- OMIM: PSEUDOVAGINAL PERINEOSCROTAL HYPOSPADIAS; PPSH (https://omim.org/entry/264600)
- PubMed: 5-α-Reductase type 2 deficiency: is there a genotype-phenotype correlation? A review (https://pubmed.ncbi.nlm.nih.gov/29858846/) - Avendaño, Andrea et al. “5-α-Reductase type 2 deficiency: is there a genotype-phenotype correlation? A review.” Hormones (Athens, Greece) vol. 17,2 (2018): 197-204. doi:10.1007/s42000-018-0013-9
- PubMed: 5-Alpha-Reductase Deficiency (https://www.ncbi.nlm.nih.gov/books/NBK539904/) - Kumar G, Barboza-Meca JJ. 5-Alpha-Reductase Deficiency. [Updated 2022 Oct 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK539904/
- PubMed: 5-Alpha reductase deficiency: a 40-year retrospective review (https://pubmed.ncbi.nlm.nih.gov/25321150/) - Okeigwe, Ijeoma, and Wendy Kuohung. “5-Alpha reductase deficiency: a 40-year retrospective review.” Current opinion in endocrinology, diabetes, and obesity vol. 21,6 (2014): 483-7. doi:10.1097/MED.0000000000000116
- PubMed: "Exogenous" 5 Alpha Reductase Deficiency: A Case Report (https://pubmed.ncbi.nlm.nih.gov/37178876/) - Levy, Brittany et al. “"Exogenous" 5 Alpha Reductase Deficiency: A Case Report.” Urology vol. 178 (2023): 147-150. doi:10.1016/j.urology.2023.05.001
- Rare Diseases: 46,XY disorder of sex development due to 5-alpha-reductase 2 deficiency (https://rarediseases.org/mondo-disease/46xy-disorder-of-sex-development-due-to-5-alpha-reductase-2-deficiency/)
- Review It Well: 04/28/2025: 5 Alpha Reductase Deficiency – What It Means, How It Happens, And What To Know (https://www.reviewitwell.com/5-alpha-reductase-deficiency/)
- Wikipedia - 5α-Reductase 2 deficiency (https://en.wikipedia.org/wiki/5%CE%B1-Reductase_2_deficiency)