Cytochrome P450 oxidoreductase deficiency

Other names: PORD
a-c Image indicates individuals' difficulty of bending the metacarpophalangeal joints(R457H mutation in POR gene)[1]
Specialty| Endocrinology

Cytochrome P450 oxidoreductase deficiency (PORD)[2] is a rare disease and inborn error of metabolism caused by deficiency of cytochrome P450 oxidoreductase (POR). POR is a 2-flavin protein that is responsible for the transfer of electrons from NADPH to all 50 microsomal cytochrome P450 (CYP450) enzymes.[3][4] This includes the steroidogenic enzymes CYP17A1 (17α-hydroxylase/17,20-lyase), CYP19A1 (aromatase), and CYP21A2 (21-hydroxylase); CYP26B1 (metabolizes retinoic acid); and the hepatic drug-metabolizing CYP450 enzymes (e.g., CYP3A4),[5] among many other CYP450 enzymes.[4] Symptoms of severe forms of PORD include ambiguous genitalia in males and females, congenital adrenal hyperplasia, cortisol deficiency, and Antley–Bixler skeletal malformation syndrome (ABS), while symptoms of mild forms include polycystic ovary syndrome in women and hypogonadism in men.[4] Maternal virilization also occurs in severe forms, due to aromatase deficiency[6] in the placenta.[4] Virilization of female infants in PORD may also be caused by alternative biosynthesis of 5α-dihydrotestosterone via the so-called "androgen backdoor pathway".[7][8] The ABS component of severe forms of PORD is probably caused by CYP26B1 deficiency, which results in retinoic acid excess and defects during skeletal embryogenesis.[4] All forms of PORD in humans are likely partial, as POR knockout in mice results in death during prenatal development.[4]

## See also[edit | edit source]

* Androgen backdoor pathway
* Cytochrome P450 reductase

## References[edit | edit source]

1. ↑ Bai, Yang; Li, Jinhui; Wang, Xiaoli (14 March 2017). "Cytochrome P450 oxidoreductase deficiency caused by R457H mutation in POR gene in Chinese: case report and literature review". Journal of Ovarian Research. 10 (1): 16. doi:10.1186/s13048-017-0312-9. ISSN 1757-2215. Archived from the original on 1 November 2023. Retrieved 1 November 2023.
2. ↑ Flück, Christa E.; Pandey, Amit V. (2019-01-01), "Human P450 Oxidoreductase Deficiency", in Huhtaniemi, Ilpo; Martini, Luciano (eds.), Encyclopedia of Endocrine Diseases (Second Edition), Academic Press, pp. 431–443, doi:10.1016/b978-0-12-801238-3.64966-8, ISBN 978-0-12-812200-6, S2CID 80510456, archived from the original on 2020-02-18, retrieved 2020-02-18
3. ↑ Pandey, Amit V.; Flück, Christa E. (May 2013). "NADPH P450 oxidoreductase: structure, function, and pathology of diseases". Pharmacology & Therapeutics. 138 (2): 229–254. doi:10.1016/j.pharmthera.2013.01.010. ISSN 1879-016X. PMID 23353702.
4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Mark A. Sperling (10 April 2014). Pediatric Endocrinology E-Book. Elsevier Health Sciences. pp. 497–. ISBN 978-1-4557-5973-6. Archived from the original on 3 November 2023. Retrieved 8 July 2023.
5. ↑ Burkhard, Fabian Z.; Parween, Shaheena; Udhane, Sameer S.; Flück, Christa E.; Pandey, Amit V. (January 2017). "P450 Oxidoreductase deficiency: Analysis of mutations and polymorphisms". The Journal of Steroid Biochemistry and Molecular Biology. 165 (Pt A): 38–50. doi:10.1016/j.jsbmb.2016.04.003. ISSN 1879-1220. PMID 27068427.
6. ↑ Parween, Shaheena; Fernández-Cancio, Mónica; Benito-Sanz, Sara; Camats, Núria; Velazquez, Maria Natalia Rojas; López-Siguero, Juan-Pedro; Udhane, Sameer S.; Kagawa, Norio; Flück, Christa E.; Audí, Laura; Pandey, Amit V. (2020-02-15). "Molecular basis of CYP19A1 deficiency in a 46, XX patient with R550W mutation in POR: Expanding the PORD phenotype". The Journal of Clinical Endocrinology and Metabolism. 105 (4): e1272–e1290. doi:10.1210/clinem/dgaa076. ISSN 1945-7197. PMID 32060549.
7. ↑ Masiutin, Maxim; Yadav, Maneesh (2023). "Alternative androgen pathways". WikiJournal of Medicine. 10: X. doi:10.15347/WJM/2023.003. S2CID 257943362.
8. ↑ Reisch N, Taylor AE, Nogueira EF, Asby DJ, Dhir V, Berry A, Krone N, Auchus RJ, Shackleton CH, Hanley NA, Arlt W (October 2019). "Alternative pathway androgen biosynthesis and human fetal female virilization". Proceedings of the National Academy of Sciences of the United States of America. 116 (44): 22294–22299. Bibcode:2019PNAS..11622294R. doi:10.1073/pnas.1906623116. PMC 6825302. PMID 31611378.

* v
* t
* e

Gonadal disorder

Ovarian|

* Polycystic ovary syndrome
* Premature ovarian failure
* Hyperthecosis

Testicular|

| Enzymatic|

* 5α-Reductase 2 deficiency
* 17β-Hydroxysteroid dehydrogenase deficiency
* Aromatase excess syndrome

|

Androgen receptor|

* Androgen insensitivity syndrome
* Mild androgen insensitivity syndrome
* Partial androgen insensitivity syndrome
* Complete androgen insensitivity syndrome
* Familial male-limited precocious puberty

Other|

* Sertoli cell-only syndrome

General|

* Hypogonadism
* Delayed puberty
* Hypergonadism
* Precocious puberty
* Hypoandrogenism
* Hypoestrogenism
* Hyperandrogenism
* Hyperestrogenism
* Postorgasmic illness syndrome
* Cytochrome P450 oxidoreductase deficiency
* Cytochrome b5 deficiency
* Androgen-dependent condition
* Aromatase deficiency
* Estrogen insensitivity syndrome
* Hypergonadotropic hypogonadism
* Hypogonadotropic hypogonadism
* Fertile eunuch syndrome
* Estrogen-dependent condition
* Premature thelarche
* Gonadotropin insensitivity
* Hypergonadotropic hypergonadism

* v
* t
* e

Inborn errors of steroid metabolism

Mevalonate
pathway|

* HMG-CoA lyase deficiency

* Hyper-IgD syndrome
* Mevalonate kinase deficiency

To cholesterol|

* 7-Dehydrocholesterol path: Hydrops-ectopic calcification-moth-eaten skeletal dysplasia
* CHILD syndrome
* Conradi-Hünermann syndrome
* Lathosterolosis
* Smith–Lemli–Opitz syndrome

* desmosterol path: Desmosterolosis

Steroids|

| Corticosteroid
(including CAH)|

* aldosterone: Glucocorticoid remediable aldosteronism

* cortisol/cortisone: CAH 17α-hydroxylase
* CAH 11β-hydroxylase

* both: CAH 3β-dehydrogenase
* CAH 21-hydroxylase
* Apparent mineralocorticoid excess syndrome/11β-dehydrogenase

|

Sex steroid|

| To androgens|

* 17α-Hydroxylase deficiency
* 17,20-Lyase deficiency
* Cytochrome b5 deficiency
* 3β-Hydroxysteroid dehydrogenase deficiency
* 17β-Hydroxysteroid dehydrogenase deficiency
* 5α-Reductase 2 deficiency
* Pseudovaginal perineoscrotal hypospadias

|

To estrogens|

* Aromatase deficiency
* Aromatase excess syndrome

Other|

* X-linked ichthyosis
* Antley–Bixler syndrome

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