GENE REFERENCE / HGNC:9936

OPN1LW

opsin 1, long wave sensitive

protein-coding geneXq28Gene information

What does this gene do?

The OPN1LW gene provides instructions for making a protein that is essential for normal color vision. This protein is found in the retina, which is the light-sensitive tissue at the back of the eye. The retina contains two types of light receptor cells, called rods and cones, that transmit visual signals from the eye to the brain. Rods provide vision in low light. Cones provide vision in bright light, including color vision. There are three types of cones, each containing a specific pigment (a photopigment called an opsin) that is most sensitive to particular wavelengths of light.

The OPN1LW gene provides instructions for making an opsin pigment that is more sensitive to light in the yellow/orange part of the visible spectrum (long-wavelength light). Cones with this pigment are called long-wavelength-sensitive or L cones. In response to light, the photopigment triggers a series of chemical reactions within an L cone. These reactions ultimately alter the cell's electrical charge, generating a signal that is transmitted to the brain. The brain combines input from all three types of cones to produce normal color vision.

The OPN1LW gene is located next to another opsin pigment gene, OPN1MW, on the X chromosome. The OPN1MW gene provides instructions for making a photopigment that is more sensitive to light at middle wavelengths (yellow/green light). Most people have one copy of the OPN1LW gene and one or more copies of the OPN1MW gene on each X chromosome. A nearby region of DNA, known as the locus control region (LCR), regulates the activity of these genes. Only the two opsin pigment genes nearest the LCR, generally the OPN1LW gene and the first copy of the OPN1MW gene, are active in the retina and contribute to color vision.

Source: MedlinePlus, National Library of Medicine. Source publication: 2020-08-18. Source review: 2015-01.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
red color blindnessMONDO:0010565 · Evaluated 2025-09-04	X-linked	DefinitiveRetina Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 351
Submissions for variants in or overlapping this gene: 388
Submissions explicitly reporting this gene: 67
Alleles reported pathogenic / likely pathogenic: 24
VariationIDs with uncertain significance: 47
VariationIDs with conflicting classifications: 0

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about OPN1LW?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 24 alleles in OPN1LW reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in OPN1LW.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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