Cytochrome P450 oxidoreductase deficiency

In a nutshell

Cytochrome P450 oxidoreductase deficiency (PORD) 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. 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), among many other CYP450 enzymes. Virilization of female infants in PORD may also be caused by alternative biosynthesis of 5α-dihydrotestosterone via the so-called "androgen backdoor pathway". 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. All forms of PORD in humans are likely partial, as POR knockout in mice results in death during prenatal development.

Related on Lably

Through Protein, Electron transfer and Electron

Lab · Class 11–12Biomolecules of Life Lab · Class 11Biomolecules — Animated Chapter Film Lab · Class 11Locomotion and Movement — Animated Chapter Film Lab · Class 4–6Food and Nutrition

Symptoms and signs

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. Maternal virilization also occurs in severe forms, due to aromatase deficiency in the placenta.

More in Health

Food and Drug AdministrationFederal agency of the United States Department of Health and Human Services Centers for Disease Control and PreventionUnited States government public health agency NauseaMedical symptom or condition SeizurePeriod of symptoms due to excessive or synchronous neuronal brain activity VomitingExpulsion of stomach contents via the mouth or nose Intravenous therapyMedication administered into a vein