View source for Cytochrome P450 oxidoreductase deficiency

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==Overview==
Cytochrome P450 oxidoreductase deficiency is a disorder of hormone production.  This condition specifically affects steroid hormones, which are needed for normal development and reproduction.  The hormonal changes associated with cytochrome P450 oxidoreductase deficiency can affect the development of the reproductive system, skeleton, and other parts of the body.

==Pathophysiology==
===Genetics===
Cytochrome P450 oxidoreductase deficiency is caused by mutations in the POR gene.  This gene provides instructions for making the enzyme cytochrome P450 oxidoreductase, which plays a critical role in the formation of steroid hormones.  This group of hormones includes testosterone and estrogen, which are essential for normal sexual development and reproduction; corticosteroids, which are involved in the body's response to stress; and aldosterone, which helps regulate the body's salt and water balance.

Mutations in the POR gene reduce the activity of cytochrome P450 oxidoreductase, which disrupts the production of steroid hormones.  Changes in sex hormones such as testosterone and estrogen lead to problems with sexual development before birth and at puberty.  Studies suggest that these abnormalities may be related, at least in part, to the abnormal production of cholesterol. Cholesterol is a substance that is altered to produce steroid hormones.  It is necessary for normal embryonic development and is involved in bone formation.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Severe cases of cytochrome P450 oxidoreductase deficiency are often given the name Antley-Bixler syndrome.

==Epidemiology and Demographics==
===Prevalence===
The prevalence of cytochrome P450 oxidoreductase deficiency is unknown. About 60 affected individuals have been reported worldwide.

==Diagnosis==
===Symptoms===
* [[Infertility]]
* Joint contractures

===Physical Examination===
====Head====
* [[Craniosynostosis]]
* Flattened mid-face
* Prominent forehead

====Ears====
* [[Low-set ears]]

====Nose====
* [[Choanal atresia]]

====Genitalia====
* [[Ambiguous genitalia]]

====Extremities====
* Joint contractures
* [[Radiohumeral synostosis]]

====Neurologic====
* Intellectual disability

==References==
{{Reflist|2}}


[[Category:Genetic disorders]]
[[Category:Disease]]