Achromatopsia is a disorder that causes problems with color vision. The retina, which is the light-sensitive tissue at the back of the eye, contains two types of light receptor cells called rods and cones. Rods provide vision in low light (night vision), while cones provide vision in bright light (daytime vision). Cones are also responsible for color vision. 

There are two types of achromatopsia: complete and incomplete. People with complete achromatopsia cannot perceive any color; they see only black, white, and shades of gray. People with incomplete achromatopsia can see some color.

People with achromatopsia may have additional problems with their vision, including an increased sensitivity to light and glare (photophobia), involuntary back-and-forth eye movements (nystagmus), and significantly reduced sharpness of vision (low visual acuity). Affected individuals may also have a small visual blind spot (scotoma), farsightedness (hyperopia), or nearsightedness (myopia).

Achromatopsia is different from the more common forms of color vision deficiency (also called color blindness), in which people can perceive color but have difficulty distinguishing between certain colors, such as red and green. One form of color blindness, called blue cone monochromacy (BCM), is sometimes considered a form of incomplete achromatopsia. 

Achromatopsia affects approximately 1 in 30,000 people worldwide. Complete achromatopsia is more common than incomplete achromatopsia.

Complete achromatopsia occurs more frequently among Pingelapese islanders, who live in parts of Micronesia in the western Pacific Ocean. Between 4 and 10 percent of people in this population have a total absence of color vision.

Variants (also called mutations) in several different genes can cause achromatopsia. Most of the genes that are associated with achromatopsia are known to play important roles in the normal functioning of cones. Variants in the CNGA3 and CNGB3 genes are the most common causes of achromatopsia.  

The CNGA3 and CNGB3 genes provide instructions for making different parts (subunits) of the cyclic nucleotide-gated (CNG) channel. These channels are found exclusively in cones and play an important role in a process called phototransduction. During phototransduction, rods and cones translate light into electrical signals. To help with this process, CNG channels transport positively charged atoms (ions) across the cell membrane and into cells. This movement of ions helps generate an electrical signal that is sent to the brain for interpretation.  

Some of the variants in the CNGA3 and CNGB3 genes that are associated with achromatopsia cause cells to produce fewer CNG channel subunits, while other variants cause cells to produce subunits that do not function properly. These changes impair the function of the CNG channels, which disrupts the flow of ions across cell membranes and impairs the cell's ability to generate electrical signals.

Some people with achromatopsia do not have one of the gene variants known to cause the condition. In these individuals, the cause of the disorder is unknown. 

Genetic Testing Information

• Genetic Testing Registry: Achromatopsia
• Genetic Testing Registry: Achromatopsia 2
• Genetic Testing Registry: Achromatopsia 3
• Genetic Testing Registry: Achromatopsia 4
• Genetic Testing Registry: Achromatopsia 5
• Genetic Testing Registry: Achromatopsia 6

Genetic and Rare Diseases Information Center

• Achromatopsia 2
• Achromatopsia 3
• Blue cone monochromatism

Patient Support and Advocacy Resources

• National Organization for Rare Disorders (NORD)

Clinical Trials

• ClinicalTrials.gov

Catalog of Genes and Diseases from OMIM

• ACHROMATOPSIA 3; ACHM3
• ACHROMATOPSIA 2; ACHM2
• ACHROMATOPSIA 6; ACHM6
• ACHROMATOPSIA 4; ACHM4
• CONE DYSTROPHY 4; COD4

Scientific Articles on PubMed

• PubMed

• Chang B, Grau T, Dangel S, Hurd R, Jurklies B, Sener EC, Andreasson S, Dollfus H, Baumann B, Bolz S, Artemyev N, Kohl S, Heckenlively J, Wissinger B. A homologous genetic basis of the murine cpfl1 mutant and human achromatopsia linked to mutations in the PDE6C gene. Proc Natl Acad Sci U S A. 2009 Nov 17;106(46):19581-6. doi: 10.1073/pnas.0907720106. Epub 2009 Nov 3. Citation on PubMed or Free article on PubMed Central
• Deeb SS. The molecular basis of variation in human color vision. Clin Genet. 2005 May;67(5):369-77. doi: 10.1111/j.1399-0004.2004.00343.x. Citation on PubMed
• Hirji N, Aboshiha J, Georgiou M, Bainbridge J, Michaelides M. Achromatopsia: clinical features, molecular genetics, animal models and therapeutic options. Ophthalmic Genet. 2018 Apr;39(2):149-157. doi: 10.1080/13816810.2017.1418389. Epub 2018 Jan 5. Citation on PubMed
• Kohl S, Baumann B, Rosenberg T, Kellner U, Lorenz B, Vadala M, Jacobson SG, Wissinger B. Mutations in the cone photoreceptor G-protein alpha-subunit gene GNAT2 in patients with achromatopsia. Am J Hum Genet. 2002 Aug;71(2):422-5. doi: 10.1086/341835. Epub 2002 Jun 20. Citation on PubMed or Free article on PubMed Central
• Kohl S, Coppieters F, Meire F, Schaich S, Roosing S, Brennenstuhl C, Bolz S, van Genderen MM, Riemslag FC; European Retinal Disease Consortium; Lukowski R, den Hollander AI, Cremers FP, De Baere E, Hoyng CB, Wissinger B. A nonsense mutation in PDE6H causes autosomal-recessive incomplete achromatopsia. Am J Hum Genet. 2012 Sep 7;91(3):527-32. doi: 10.1016/j.ajhg.2012.07.006. Epub 2012 Aug 16. Citation on PubMed or Free article on PubMed Central
• Kohl S, Hamel C. Clinical utility gene card for: Achromatopsia - update 2013. Eur J Hum Genet. 2013 Nov;21(11). doi: 10.1038/ejhg.2013.44. Epub 2013 Mar 13. No abstract available. Citation on PubMed or Free article on PubMed Central
• Kohl S, Jagle H, Wissinger B, Zobor D. Achromatopsia. 2004 Jun 24 [updated 2018 Sep 20]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2025. Available from http://www.ncbi.nlm.nih.gov/books/NBK1418/ Citation on PubMed
• Kohl S, Marx T, Giddings I, Jagle H, Jacobson SG, Apfelstedt-Sylla E, Zrenner E, Sharpe LT, Wissinger B. Total colourblindness is caused by mutations in the gene encoding the alpha-subunit of the cone photoreceptor cGMP-gated cation channel. Nat Genet. 1998 Jul;19(3):257-9. doi: 10.1038/935. Citation on PubMed
• Michalakis S, Gerhardt M, Rudolph G, Priglinger S, Priglinger C. Achromatopsia: Genetics and Gene Therapy. Mol Diagn Ther. 2022 Jan;26(1):51-59. doi: 10.1007/s40291-021-00565-z. Epub 2021 Dec 3. Citation on PubMed
• Sundin OH, Yang JM, Li Y, Zhu D, Hurd JN, Mitchell TN, Silva ED, Maumenee IH. Genetic basis of total colourblindness among the Pingelapese islanders. Nat Genet. 2000 Jul;25(3):289-93. doi: 10.1038/77162. Citation on PubMed
• Thiadens AA, den Hollander AI, Roosing S, Nabuurs SB, Zekveld-Vroon RC, Collin RW, De Baere E, Koenekoop RK, van Schooneveld MJ, Strom TM, van Lith-Verhoeven JJ, Lotery AJ, van Moll-Ramirez N, Leroy BP, van den Born LI, Hoyng CB, Cremers FP, Klaver CC. Homozygosity mapping reveals PDE6C mutations in patients with early-onset cone photoreceptor disorders. Am J Hum Genet. 2009 Aug;85(2):240-7. doi: 10.1016/j.ajhg.2009.06.016. Epub 2009 Jul 16. Citation on PubMed or Free article on PubMed Central
• Thiadens AA, Slingerland NW, Roosing S, van Schooneveld MJ, van Lith-Verhoeven JJ, van Moll-Ramirez N, van den Born LI, Hoyng CB, Cremers FP, Klaver CC. Genetic etiology and clinical consequences of complete and incomplete achromatopsia. Ophthalmology. 2009 Oct;116(10):1984-9.e1. doi: 10.1016/j.ophtha.2009.03.053. Epub 2009 Jul 9. Citation on PubMed
• Tsang SH, Sharma T. Rod Monochromatism (Achromatopsia). Adv Exp Med Biol. 2018;1085:119-123. doi: 10.1007/978-3-319-95046-4_24. Citation on PubMed