Gene
POR
cytochrome p450 oxidoreductase
- HGNC 9208(opens in a new tab)
- Ensembl gene ENSG00000127948(opens in a new tab)
- NCBI Gene 5447(opens in a new tab)
Summary
- Cytogenetic location
- 7q11.23
- Coordinates
- Chromosome 7: 75,915,155–75,986,855 (GRCh38)
- Exons
- 16 exons across 71.7 kb
- Protein
- 677 amino acids
- Inheritance
- Autosomal recessive
- Also known as
- CYPOR, FLJ26468
- MANE Select transcript
- ENST00000461988.6NM_001395413.1
- Locus type
- gene with protein product
- Very high
- Confident
- Low
- Very low
Reference genomeGRCh38hg38
Positions on gene and variant pages follow this choice, in this browser.
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Congenital Adrenal Hyperplasia
- Antley-Bixler syndrome with disordered steroidogenesis (POR deficiency)Autosomal recessive
Cytochrome P450 oxidoreductase deficiency, causing combined steroid hormone defects with or without skeletal malformations.
- ClinGen rates the link definitive
- 3 GenCC submitters rate it definitive or strong
- Autosomal recessive
Congenital adrenal hyperplasia (CAH) is an inherited endocrine disorder caused by a steroidogenic enzyme deficiency that is characterized by adrenal insufficiency and variable degrees of hyper or hypo androgyny manifestations, depending of the type and the severity of the disease.
- 2 GenCC submitters rate it definitive or strong
What knowing changes
Glucocorticoid replacement (hydrocortisone in children, prednisone/dexamethasone in adults); mineralocorticoid replacement for salt-wasting (fludrocortisone); adrenalectomy for severe medically refractory hyperandrogenism; stress dosing protocols
Syndromic Craniosynostosis
Conditions combining early skull suture closure with other features, including Apert, Crouzon, Pfeiffer, Muenke and Saethre-Chotzen syndromes, caused by genes such as FGFR2, FGFR3, FGFR1, TWIST1, TCF12 and ERF.
- ClinGen rates the link definitive
- 3 GenCC submitters rate it definitive or strong
What knowing changes
Early diagnosis allows timely surgery and monitoring of head growth, vision and hearing; milder forms such as Muenke syndrome can go unrecognised in adults, which is relevant to family planning.
Inheritance
- Autosomal recessive
- It takes a changed copy from each parent. With one, you are a carrier and usually unaffected; when both parents are carriers, each child has a one-in-four chance of inheriting two.
How POR is laid out
- Coding sequence
- Untranslated region
- Intron
- Direction of transcription
- Known disease-causing sites
- Stretches short reads find hard
Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.
Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).
Nearby genes from Ensembl release 116, on GRCh38.
Exons make up 2.4 kb of the gene's 71.7 kb; 2,034 of those bases code for the protein.
How a genome test reads POR
87
positions in POR where ClinVar classes a change as pathogenic or likely pathogenic
None of them falls in a region short reads find hard.
A whole genome covers all 71.7 kb of POR, introns included, not only the 2.4 kb of exons.
Traits linked to POR
The Human Phenotype Ontology lists these as features of the rare conditions POR can cause. Each trait's page lists the other genes linked to it.
Abnormality of limbs
- Broad foot
- Elbow ankylosis
- Elbow flexion contracture
- Fusion of upper and lower arm bones
- Large hands
- Limited elbow extension
- Long slender fingers
- Rocker bottom foot
Show 25 more traits
- Abnormal feet structure
- Abnormality of end part of long bone of hand
- Abnormality of the hand
- Abnormality of the knuckle
- Abnormality of the wrist
- Bowed thighbone
- Bowing of the long bones
- Club feet
- Curvature of digit
- Fused forearm bones
- Fused long bones of hand
- Fusion of the long bones of the feet
- Long palm
- Outward turned elbows
- Radioulnar dislocation
- Short fingers or toes
- Shortened long bone of hand
- Shortening of all outermost bones of the fingers
- Talipes
- Ulnar deviation of the wrist
- Fused ankle bones
- Fusion of innermost shinbone and calf bone
- Curving of inner forearm bone
- Fused wrist bones
- Joint contracture of the hand
Abnormality of the genitourinary system
- Abnormal external genitalia
- Abnormal female external genitalia
- Abnormal male external genitalia morphology
- Abnormal ovarian morphology
- Decreased fertility
- Enlarged clitoris
- Fused labia majora
- Low sperm count
Show 24 more traits
- Ovarian cyst
- Polycystic ovaries
- Primary amenorrhea
- Small uterus
- Ambiguous external genitalia
- Enlarged ovaries with cysts
- Hypospadias
- Increased size of the clitoris
- Short penis
- Undescended testes
- Absent kidney on one side
- Dilatation of the renal pelvis
- Urinary tract abnormalities
- Vesicoureteral reflux
- Abnormally closed or absent vagina
- Abnormally shaped kidney
- Chordee
- Cleft of scrotum
- Fused inner lips
- Horseshoe kidney
- Small labia majora
- Smaller than typical growth of scrotum
- Underdeveloped labia
- Vesicovaginal fistula
Abnormality of head or neck
- Big calvaria
- Deformity of the skull
- Midface retrusion
- Narrowing of the rear opening of the nasal cavity
- Wide nose
- Abnormal facial shape
- Blockage of the rear opening of the nasal cavity
- Broad head shape
Show 16 more traits
- Bulbous nose
- Depressed nasal bridge
- Frontal bossing
- High, narrow palate
- Narrow mouth
- Short nose
- Tall shaped head
- Wider-than-typical soft spot of skull
- Midfrontal capillary hemangioma
- Abnormally small head
- Cloverleaf cranium shape
- Coronal craniosynostosis
- Lambdoidal craniosynostosis
- Long philtrum
- Temporal bossing
- Zygomatic flattening
Abnormality of the endocrine system
- Elevated circulating 17-hydroxyprogesterone concentration
- Abnormal response to ACTH stimulation test
- Abnormal circulating pregnenolone concentration
- Abnormal response to human chorionic gonadotrophin stimulation test
- Adrenal insufficiency
- Decreased circulating androstenedione concentration
- Decreased circulating dehydroepiandrosterone concentration
- Decreased circulating dehydroepiandrosterone-sulfate concentration
Show 15 more traits
- Decreased circulating renin concentration
- Decreased serum estradiol
- Elevated serum 11-deoxycortisol
- Enlarged adrenal glands
- Increased circulating ACTH level
- Increased circulating progesterone
- Low blood cortisol level
- Decreased circulating androgen concentration
- Decreased circulating inhibin B concentration
- Delayed puberty
- Elevated circulating follicle stimulating hormone level
- Elevated circulating luteinizing hormone level
- Increased circulating corticosterone level
- Congenital adrenal hyperplasia
- Decreased serum progesterone
External links
Gene records
Transcript
Protein
Where this comes from
- HGNC: the gene's symbol, name, other symbols and location.
- MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
- GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
- The ACMG secondary findings list, SF v3.2.
- ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
- The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
- Data release 2026.10.16-c6eea6bf.
Cite this page
Dante Labs. (n.d.). POR gene: cytochrome p450 oxidoreductase. Retrieved 17 October 2026, from https://dantelabs.com/genes/por
Dante Labs. POR gene: cytochrome p450 oxidoreductase [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/por
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