OPN1MW

Chr XXLRX-linked

opsin 1, medium wave sensitive

Also known as: CBBM, CBD, COD5, GCP, GOP, OPN1MW1

NCBI Gene: 2652ENSG00000268221UniProt: P04001

This gene encodes for a light absorbing visual pigment of the opsin gene family. The encoded protein is called green cone photopigment or medium-wavelength sensitive opsin. Opsins are G-protein coupled receptors with seven transmembrane domains, an N-terminal extracellular domain, and a C-terminal cytoplasmic domain. The long-wavelength opsin gene and multiple copies of the medium-wavelength opsin gene are tandemly arrayed on the X chromosome and frequent unequal recombination and gene conversion may occur between these sequences. X chromosomes may have fusions of the medium- and long-wavelength opsin genes or may have more than one copy of these genes. Defects in this gene are the cause of deutanopic colorblindness. [provided by RefSeq, Mar 2009]

Primary Disease Associations & Inheritance

Blue cone monochromacyMIM #303700
XLR
Colorblindness, deutanMIM #303800
X-linked
UniProtColorblindness, partial, deutan series
UniProtCone dystrophy 5
308
ClinVar variants
160
Pathogenic / LP
0.04
pLI score
0
Active trials
Clinical Summary— OPN1MW
⚡
Population Constraint (gnomAD)
Low constraint (pLI 0.04) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
160 Pathogenic / Likely Pathogenic· 31 VUS of 308 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
1.78LOEUF
pLI 0.038
Z-score 0.42
OE 0.73 (0.29–1.78)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
0.75Z-score
OE missense 0.69 (0.52–0.93)
32 obs / 46.3 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.73 (0.29–1.78)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.69 (0.52–0.93)
0≤0.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.1.65
0≤1.21.6
LoF obs/exp: 2 / 2.7Missense obs/exp: 32 / 46.3Syn Z: -2.35

ClinVar Variant Classifications

308 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic157
Likely Pathogenic3
VUS31
Likely Benign13
Benign3
Conflicting1
157
Pathogenic
3
Likely Pathogenic
31
VUS
13
Likely Benign
3
Benign
1
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
1
4
152
0
157
Likely Pathogenic
0
0
3
0
3
VUS
0
17
14
0
31
Likely Benign
0
12
0
1
13
Benign
0
1
0
2
3
Conflicting
—1
Total1341693208

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

OPN1MW · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Gene2Phenotype Curations

OPN1MW-related blue cone monochromacy

definitive
Monoallelic X HemizygousUndeterminedUncertain
Eye
G2P ↗

Gene2Phenotype curations · DECIPHER consortium patient cohort (public variants) · deciphergenomics.org

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM

Blue cone monochromacy

MIM #303700

Molecular basis of disorder known

X-linked recessive

Colorblindness, deutan

MIM #303800

Molecular basis of disorder known

X-linked
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
Phenotyping and genotyping inherited retinal diseases: Molecular genetics, clinical and imaging features, and therapeutics of macular dystrophies, cone and cone-rod dystrophies, rod-cone dystrophies, Leber congenital amaurosis, and cone dysfunction syndromes.
Georgiou M et al.·Prog Retin Eye Res
2024Review
The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies.
De Silva SR et al.·Prog Retin Eye Res
2021Review
Monogenic Retinal Diseases Associated With Genes Encoding Phototransduction Proteins: A Review.
Wong WM et al.·Clin Exp Ophthalmol
2025Review
Unravelling genotype-phenotype correlations in Stargardt disease using patient-derived retinal organoids.
Watson A et al.·Cell Death Dis
2025
Novel OPN1LW/OPN1MW Exon 3 Haplotype-Associated Splicing Defect in Patients with X-Linked Cone Dysfunction.
Stingl K et al.·Int J Mol Sci
2022Cohort
Unique Haplotypes in OPN1LW as a Common Cause of High Myopia With or Without Protanopia: A Potential Window Into Myopic Mechanism.
Wang Y et al.·Invest Ophthalmol Vis Sci
2023Functional
Ocular genetics in the Japanese population.
Hotta Y et al.·Jpn J Ophthalmol
2024Review
Inherited Retinal Diseases with High Myopia: A Review.
Liu C et al.·Genes (Basel)
2025Review
Gene therapy in color vision deficiency: a review.
El Moussawi Z et al.·Int Ophthalmol
2021Review
Evaluation of Retinal Structure and Visual Function in Blue Cone Monochromacy to Develop Clinical Endpoints for L-opsin Gene Therapy.
Cideciyan AV et al.·Int J Mol Sci
2024
Top 10 resultsSearch PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Top 5 resultsSearch Europe PMC ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools