GENE REFERENCE / HGNC:2153

CNGB3

cyclic nucleotide gated channel subunit beta 3

protein-coding gene8q21.3Gene information

What does this gene do?

The CNGB3 gene provides instructions for making one part (the beta subunit) of the cyclic nucleotide-gated (CNG) channel. These channels are found exclusively in light-sensing (photoreceptor) cells called cones, which are located in a specialized tissue at the back of the eye (retina). Cones provide color vision and vision in bright light (daytime vision). Other photoreceptor cells, called rods, provide vision in low light (night vision).

CNG channels are openings in the cell membrane that transport positively charged atoms (ions) into cells. The CNG channels in cones remain open in low light, allowing ions to flow in. When light enters the eye, these channels close, stopping the flow of ions. This change in ion transport alters the cone's electrical charge, which ultimately generates a signal. This signal is sent to the brain, where it combines with other visual information and is interpreted as vision. The process of translating light into an electrical signal is called phototransduction.

Source: MedlinePlus, National Library of Medicine. Source publication: 2025-08-14. Source review: 2025-08.

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
CNGB3-related retinopathyMONDO:0100446 · Evaluated 2022-05-24	Autosomal recessive	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: 1,493
Submissions for variants in or overlapping this gene: 2,681
Submissions explicitly reporting this gene: 2,574
Alleles reported pathogenic / likely pathogenic: 350
VariationIDs with uncertain significance: 467
VariationIDs with conflicting classifications: 60

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 CNGB3?

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 350 alleles in CNGB3 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 CNGB3.

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

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