CNGA1 gene


Gene (OMIM No.)
Function of gene/protein
  • Protein: alpha subunit of the rod cGMP-gated cation channel
  • Involved in the last stage of the phototransduction pathway
  • Closure of the CNGA1/CNAGB1 channel in the rod outer segment membrane ultimately leads to hyperpolarisation
Clinical phenotype
(OMIM phenotype no.)
  • Autosomal recessive
Signs for RP
  • Vessels attenuation
  • Waxy optic disc pallor
  • Bone spicule pigmentation in the mid-periphery (sparse)
  • Retinal degeneration involving the macular in advanced stages
Visual functionAutosomal recessive CNGA1 retinopathy
  • Early-onset nyctalopia, usually in the 1st decade
  • VF loss usually during the 3rd decade of life but can be as early as the 1st decade
  • Gradual decline of BCVA from the 4th decade
Systemic features
  • No extraocular features reported
Key investigations
  • ERG: rod-cone dystrophy pattern or non-recordable
  • FAF: Central hyper-AF macular ring
  • OCT: Preserved outer retinal layers within the hyper-AF ring while there is outer retinal loss and beyond the ring
Molecular diagnosisNext generation sequencing
  • Targeted gene panels (retinal)
  • Whole exome sequencing
  • Whole genome sequencing
Therapies under research
  • None at present
Further information

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  1.  Dhallan, R. S., Macke, J. P., Eddy, R. L., Shows, T. B., Reed, R. R., Yau, K.-W., Nathans, J. Human rod photoreceptor cGMP-gated channel: amino acid sequence, gene structure, and functional expression. J. Neurosci. 12: 3248-3256, 1992
  2.  Dryja, T. P., Finn, J. T., Peng, Y.-W., McGee, T. L., Berson, E. L., Yau, K.-W. Mutations in the gene encoding the alpha subunit of the rod cGMP-gated channel in autosomal recessive retinitis pigmentosa. Proc. Nat. Acad. Sci. 92: 10177-10181, 1995
  3.  Zhong, H., Molday, L. L., Molday, R. S., Yau, K.-W. The heteromeric cyclic nucleotide-gated channel adopts a 3A:1B stoichiometry. Nature 420: 193-198, 2002
  4.  Katagiri S, Akahori M, Sergeev Y et al. Whole Exome Analysis Identifies Frequent CNGA1 Mutations in Japanese Population with Autosomal Recessive Retinitis Pigmentosa. PLoS ONE. 2014;9(9):e108721
  5.  Jin X, Qu LH, Hou BK, et al. Novel compound heterozygous mutation in the CNGA1 gene underlie autosomal recessive retinitis pigmentosa in a Chinese family. Biosci Rep. 2016;36(1):e00289
  6.  Gao Q, Liu Y, Lei X, et al. A Novel CNGA1 Gene Mutation (c.G622A) of Autosomal Recessive Retinitis Pigmentosa Leads to the CNGA1 Protein Reduction on Membrane. Biochem Genet. 2019;57(4):540-554
  7.  Zhang Q, Zulfiqar F, Riazuddin SA, et al. Autosomal recessive retinitis pigmentosa in a Pakistani family mapped to CNGA1 with identification of a novel mutation. Mol Vis. 2004;10:884-889

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Updated on November 30, 2020

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