RDH8: Retinol Dehydrogenase 8
Key enzyme in the visual cycle, converting all-trans-retinal to all-trans-retinol in photoreceptor cells.
Gene Information Card
| Symbol | RDH8 |
|---|---|
| Full Name | Retinol Dehydrogenase 8 |
| Gene Type | Protein coding |
| Chromosomal Location | 19p13.2 |
| NCBI Gene ID | 595 ncbi.nlm.nih.gov/gene/595 |
| Ensembl ID | ENSG00000105699 |
| UniProt ID | Q9NYR8 |
| OMIM ID | 608575 |
| HGNC ID | 9968 |
| Aliases | PRRDH, RDH, SDR16C2 |
Description
RDH8 (retinol dehydrogenase 8) encodes an enzyme belonging to the short-chain dehydrogenase/reductase (SDR) family. It is specifically expressed in the retinal pigment epithelium and photoreceptor cells, where it catalyzes the reduction of all-trans-retinal to all-trans-retinol, a critical step in the visual cycle. This enzyme helps clear all-trans-retinal from photoreceptors after photobleaching, preventing retinal toxicity and maintaining vision.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Retinitis pigmentosa | Loss-of-function mutations impair all-trans-retinal clearance, leading to accumulation of toxic retinoids and photoreceptor cell death. | ClinVar, OMIM |
| Fundus albipunctatus | Deficient RDH8 activity disrupts the visual cycle, causing delayed dark adaptation and white flecks in the retina. | OMIM |
| Age-related macular degeneration | Dysregulation of retinal recycling may contribute to oxidative stress and drusen formation. | NCBI Gene, literature |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Retina | 45.2 | High |
| Retinal pigment epithelium | 38.7 | High |
| Testis | 2.1 | Low |
| Brain | 0.8 | Not detected |
| Liver | 0.5 | Not detected |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| ARPE-19 (retinal pigment epithelium) | 52.3 | High expression |
| Y79 (retinoblastoma) | 18.6 | Moderate expression |
| HEK293 | 0.2 | Not detected |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.487C>T (p.Arg163Trp) | Missense | Rare | Reduced enzymatic activity; associated with retinitis pigmentosa |
| c.1A>G (p.Met1Val) | Start loss | Rare | Loss of protein expression; pathogenic in retinal degeneration |
| c.832G>A (p.Gly278Arg) | Missense | Rare | Impaired substrate binding; reported in fundus albipunctatus |
Mutation functional classification
Loss of Function (LOF)
Missense and start-loss mutations reduce or abolish retinol dehydrogenase activity, leading to retinal toxicity and degeneration.
Gain of Function (GOF)
No gain-of-function mutations reported for RDH8.
Dominant Negative (DN)
No dominant-negative mutations described; most pathogenic variants are recessive.
View complete mutation data：
Gene Ontology (GO)
| • retinol dehydrogenase activity (GO:0004745) | • retinoid metabolic process (GO:0001523) |
| • visual perception (GO:0007601) | • integral component of membrane (GO:0016021) |
| • endoplasmic reticulum (GO:0005783) |
Pathways
• Retinol metabolism (KEGG: hsa00830)
• Visual cycle (Reactome: R-HSA-2453902)
Protein Summary
RDH8 is a 317-amino acid membrane-bound enzyme localized to the endoplasmic reticulum and photoreceptor outer segments. It belongs to the short-chain dehydrogenase/reductase superfamily and uses NADPH as a cofactor to reduce all-trans-retinal to all-trans-retinol. This reaction is essential for regenerating 11-cis-retinal and preventing retinaldehyde toxicity. The protein is highly conserved in vertebrates and expressed predominantly in the retina.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| RDH8 Knockout HEK293 Cell Line | EDJ-KQ10802 | Human | 50700 | Details Get a Quote |
| RDH8 Knockout HeLa Cell Line | EDJ-KQ56182 | Human | 50700 | Details Get a Quote |
| RDH8 Knockout A-549 Cell Line | EDJ-KQ64672 | Human | 50700 | Details Get a Quote |
| RDH8 Knockout HCT 116 Cell Line | EDJ-KQ73121 | Human | 50700 | Details Get a Quote |
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