CYB5R1
protein-codingcytochrome b5 reductase 1
Gene summary
Predicted to enable FAD binding activity and cytochrome-b5 reductase activity, acting on NAD(P)H. Predicted to be involved in bicarbonate transport. Located in extracellular exosome; membrane; and mitochondrion. [provided by Alliance of Genome Resources, Jun 2026]
- NQO3A2
MANE transcript
Inheritance
ClinVar variants
Top phenotype
gnomAD constraint
Max pathogenic AF
Genomic locus
External References & Databases
Transcript & Mutation Effects
hg38 • Region Span ~5.4 kbGenCC Phenotypes & Disease Associations
Curated gene-disease validity assertions and inheritance patterns
No GenCC data available for this gene.
ClinVar Associated Diseases & Phenotypes
Reported disease conditions connected to CYB5R1 variants in ClinVar
ClinVar Variants & Pathogenicity by Type
Statistics based on transcript NM_016243.3. Only rare variants are included.
We include only reliable ClinVar variants with their consequences to MANE Select, MANE Plus Clinical transcripts, or transcripts with TSL equal to 1. Click a count to filter the variants table below.
Slight differences between displayed counts and ClinVar may occur due to a different transcript/consequence chosen by our variant effect predictor, or because we classify Benign/Likely benign as Likely benign and Pathogenic/Likely pathogenic as Likely pathogenic.
| Effect | PathogenicP | Likely pathogenicLP | VUS | Likely benignLB | BenignB | Sum |
|---|---|---|---|---|---|---|
| synonymous | 2 | 1 | 3 | |||
| missense | 46 | 46 | ||||
| nonsense | 0 | |||||
| start loss | 0 | |||||
| frameshift | 0 | |||||
| splice donor/acceptor (+/-2bp) | 6 | 6 | ||||
| Total | 0 | 0 | 54 | 1 | 0 | 55 |
Transcript Catalog
Annotated transcript isoforms across RefSeq and Ensembl databases
| Transcript ID | Source | Protein ID | Coding Exons | MANE Status |
|---|---|---|---|---|
| RefSeq | NP_057327.2 | 9 | MANE Select | |
| Ensembl | ENSP00000356218.4 | 9 | MANE Select | |
| Ensembl | ENSP00000396382.1 | 6 | Standard | |
| Ensembl | ENSP00000563494.1 | 7 | Standard |
Gene Ontology (GO) Annotations & Pathways
Biological processes, molecular functions, cellular components and pathways
Pathways ConsensusPathDB
- Amino sugar and nucleotide sugar metabolism - Homo sapiens (human)
- Oxidation by Cytochrome P450
- O2/CO2 exchange in erythrocytes
- Transport of small molecules
- Platelet degranulation
Biological Process
- platelet degranulation
- bicarbonate transport
- sterol biosynthetic process
- oxidation-reduction process
Molecular Function
- cytochrome-b5 reductase activity, acting on NAD(P)H
- protein binding
- FAD binding
Cellular Component
- mitochondrion
- endoplasmic reticulum membrane
- plasma membrane
- membrane
- integral component of membrane
gnomAD Constraint
Source:
- Gene type
- protein_coding
- Transcript type
- protein_coding
- Transcript
- ENST00000367249
- Coding exons
- 9
- Length
- 5412
- Individuals with no LoFs
- 125690
- Homozygous LoFs
- 0
- Heterozygous LoFs
- 58
- Defined
- 125748
- p
- 0.000231
| Z-Score | Observed | Expected | Observed/Expected | Mutation Rate | Total Possible | |
|---|---|---|---|---|---|---|
| Missense | 0.510 | 155 | 174 | 0.891 | 0.00000945 | 1944 |
| Missense (PolyPhen) | 64 | 75.374 | 0.8491 | 864 | ||
| Synonymous | -0.696 | 77 | 69.6 | 1.11 | 0.00000351 | 644 |
| Loss of Function | 0.470 | 14 | 16.0 | 0.873 | 9.23e-7 | 173 |
Population LoF Frequency
| Population | CAF | p-value | Status |
|---|---|---|---|
| African | 0.00031 | 0.00031 | rare |
| Latino/Admixed American | 0.00023 | 0.00023 | rare |
| Ashkenazi Jewish | 0 | 0.0 | absent |
| East Asian | 0.00022 | 0.00022 | rare |
| Finnish | 0.00023 | 0.00023 | rare |
| European (Non-Finnish) | 0.00026 | 0.00025 | rare |
| South Asian | 0.00020 | 0.00020 | rare |
| Other | 0.00037 | 0.00033 | rare |
dbNSFP Gene Annotations
Source:
- Function
- FUNCTION: NADH-cytochrome b5 reductases are involved in desaturation and elongation of fatty acids, cholesterol biosynthesis, drug metabolism, and, in erythrocyte, methemoglobin reduction. {ECO:0000250}.;
Recessive Scores
- pRec
- 0.130
Intolerance Scores
- LoFtool
- 0.367
- RVIS EVS
- -0.14
- RVIS percentile EVS
- 43.57
Essentials
- Essential (CRISPR)
- N
- Essential (CRISPR2)
- N
- Essential (gene trap)
- N
- Indispensability pred.
- E
- Indispensability score
- 0.975
Gene Damage Prediction
| All | Recessive | Dominant | |
|---|---|---|---|
| Mendelian | Medium | Medium | Medium |
| Primary Immunodeficiency | Medium | Medium | Medium |
| Cancer | Medium | Medium | Medium |