Cytochrome b5 deficiency

Cytochrome b5 deficiency
Specialty	Endocrinology

Cytochrome b₅ deficiency is a rare condition and form of isolated 17,20-lyase deficiency caused by deficiency in cytochrome b₅, a small hemoprotein that acts as an allosteric factor to facilitate the interaction of CYP17A1 (17α-hydroxylase/17,20-lyase) with P450 oxidoreductase (POR), thereby allowing for the 17,20-lyase activity of CYP17A1.^[1]^[2]^[3] The condition affects both adrenal and gonadal androgen biosynthesis and results in male pseudohermaphroditism.^[1] The principal biological role of cytochrome b₅ is reduction of methemoglobin, so cytochrome b₅ deficiency can also result in elevated methemoglobin levels and/or methemoglobinemia, similarly to deficiency of cytochrome b₅ reductase (methemoglobin reductase).^[1]

References

^ ^a ^b ^c Mark A. Sperling (10 April 2014). Pediatric Endocrinology E-Book. Elsevier Health Sciences. pp. 498–. ISBN 978-1-4557-5973-6.
^ Mansouri A, Lurie AA (January 1993). "Concise review: methemoglobinemia". Am. J. Hematol. 42 (1): 7–12. doi:10.1002/ajh.2830420104. PMID 8416301. S2CID 221426714.
^ "Congenital methemoglobinemia with cytochrome b5 deficiency". N. Engl. J. Med. 315 (14): 893–4. October 1986. doi:10.1056/NEJM198610023151415. PMID 3748110.

Online Mendelian Inheritance in Man (OMIM): 250790 – Methemoglobinemia due to deficiency of cytochrome b₅

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

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

Aldosterone	Hyperaldosteronism Primary aldosteronism Conn syndrome Bartter syndrome Glucocorticoid remediable aldosteronism AME Liddle's syndrome 17α CAH Pseudohypoaldosteronism
Cortisol	Cushing's syndrome Pseudo-Cushing's syndrome Steroid-induced osteoporosis
Sex hormones	21α CAH 11β CAH

Hypofunction

Aldosterone	Hypoaldosteronism 21α CAH 11β CAH
Cortisol	CAH Lipoid 3β 11β 17α 21α
Sex hormones	17α CAH Inborn errors of steroid metabolism
Adrenal insufficiency	Adrenal crisis Adrenalitis Xanthogranulomatous Addison's disease Waterhouse–Friderichsen syndrome

This article about an endocrine, nutritional, or metabolic disease is a stub. You can help Wikipedia by expanding it.

This page was last edited on 31 October 2023, at 01:12