Cyclic Nucleotide-Gated Channel, Alpha-3

Alternative Names

  • CNGA3
  • Cone Photoreceptor cGMP Channel
  • Cyclic Nucleotide-Gated Channel, Olfactory, 3
  • CNG3
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OMIM Number




Uniprot ID



53,000 bases

No. of Exons


No. of isoforms


Protein Name

Cyclic Nucleotide-Gated Cation Channel Alpha-3

Molecular Mass

78838 Da

Amino Acid Count


Genomic Location


Gene Map Locus


The CNGA3 gene (Cyclic Nucleotide Gated Channel, Alpha-3) gene codes for the alpha-subunit of the cGMP gated cation (CNG) channel in human cone photoreceptors. Functional cGMP cation channels are heteromeric, composed of two alpha and two beta subunits. These CNG channels are the final critical effectors of the phototransduction cascade. In the dark, with high cGMP levels in the cone cells, cGMP binds to the CNG channels, in effect 'opening' these channels, and permitting an influx of cations that cause a depolarization of the cones. In the presence of light, cGMP levels are lowered, resulting in the closure of these channels, and consequent cone hyperpolarization.

Orthologous CNGA3 knockout mice show complete absence of physiologically measurable cone function, a decrease in the number of cones in the retina, and morphologic abnormalities of the remaining cones. In humans, mutations in CNGA3 result in achromatopsia, a congenital disorder characterized by a complete absence of functional cones in the retina, and accompanied by other visual defects like photophobia and nystagmus.

Epidemiology in the Arab World

View Map
Variant NameCountryGenomic LocationClinvar Clinical SignificanceCTGA Clinical Significance Condition(s)HGVS ExpressionsdbSNPClinvar
NM_001298.3:c.1114C>TUnited Arab EmiratesNC_000002.12:g.98396284C>TPathogenicLikely PathogenicAchromatopsia 2NG_009097.1:g.55130C>T; NM_001298.3:c.1114C>T; NP_001289.1:p.Pro372Ser1464167194812281
NM_001298.3:c.1190G>TUnited Arab EmiratesNC_000002.12:g.98396360G>TLikely Pathogenic, PathogenicAchromatopsia 2NG_009097.1:g.55206G>T; NM_001298.3:c.1190G>T; NP_001289.1:p.Gly397Val1558820319
NM_001298.3:c.1457G>AUnited Arab EmiratesNC_000002.12:g.98396627G>ALikely PathogenicDrug Response, Likely PathogenicAchromatopsia 2; Drug Metabolism, Poor, CYP2D6-RelatedNG_009097.1:g.55473G>A; NM_001298.3:c.1457G>A; NP_001289.1:p.Cys486Tyr786205531191121
NM_001298.3:c.1495C>TUnited Arab EmiratesNC_000002.12:g.98396665C>TPathogenicLikely PathogenicAchromatopsia 2NG_009097.1:g.55511C>T; NM_001298.3:c.1495C>T; NP_001289.1:p.Arg499Ter13866419681075088
NM_001298.3:c.1579C>ASaudi ArabiaNC_000002.12:g.98396749C>AUncertain SignificanceLikely PathogenicLeber Congenital Amaurosis 1NG_009097.1:g.55595C>A; NM_001298.3:c.1579C>A; NP_001289.1:p.Leu527Met375928335988792
NM_001298.3:c.556C>TSaudi Arabiachr2:98389764PathogenicAchromatopsia 2NG_009097.1:g.48610T>C; NM_001298.3:c.556C>T; NP_001289.1:p.Leu186Phe
NM_001298.3:c.847C>T United Arab EmiratesNC_000002.12:g.98396017C>TLikely Pathogenic, PathogenicLikely Pathogenic, PathogenicAchromatopsia 2NG_009097.1:g.54863C>T; NM_001298.3:c.847C>T ; NP_001289.1:p.Arg283Trp1048936139474
NM_001298.3:c.967G>CUnited Arab EmiratesNC_000002.12:g.98396137G>CPathogenic, Uncertain SignificanceLikely PathogenicAchromatopsia 2NG_009097.1:g.54983G>C; NM_001298.3:c.967G>C; NP_001289.1:p.Ala323Pro146195955284032
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