Skip navigation

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

URL of this page:

NYX gene


Normal Function

The NYX gene provides instructions for making a protein called nyctalopin, which plays an important role in a specialized tissue at the back of the eye called the retina. Within the retina, nyctalopin is located on the surface of light-detecting cells called photoreceptors. The retina contains two types of photoreceptors: rods and cones. Rods are responsible for vision in low light. Cones provide vision in bright light, including color vision.

Nyctalopin appears to play a critical role in normal vision. Studies suggest the protein helps relay visual signals from rods and cones to other retinal cells called bipolar cells. This signaling is an essential step in the transmission of visual information from the eyes to the brain.

Health Conditions Related to Genetic Changes

X-linked congenital stationary night blindness

More than 50 mutations in the NYX gene have been identified in people with X-linked congenital stationary night blindness. Mutations in this gene are responsible for the complete form of the disorder, which is characterized by difficulty seeing in low light (night blindness), loss of sharpness (reduced acuity), severe nearsightedness (high myopia), involuntary movements of the eyes (nystagmus), and eyes that do not look in the same direction (strabismus).

Many NYX mutations change single protein building blocks (amino acids) in nyctalopin. NYX mutations can change the size or shape of the protein or prevent it from attaching to the surface of photoreceptor cells. A loss of functional nyctalopin disrupts the ability of photoreceptor cells to transmit visual signals, which impairs vision. The function of rods is severely disrupted, while the function of cones is only mildly affected.

More About This Health Condition

Other disorders

At least two mutations in the NYX gene have been found to cause high myopia without the other vision problems characteristic of X-linked congenital stationary night blindness. The mutations responsible for high myopia each change a single amino acid in nyctalopin, which is predicted to result in an unstable protein. Researchers are uncertain why these mutations cause high myopia without any other vision abnormalities.

Other Names for This Gene

  • CLRP
  • CSNB1
  • CSNB1A
  • CSNB4
  • leucine-rich repeat protein
  • MGC138447

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Bech-Hansen NT, Naylor MJ, Maybaum TA, Sparkes RL, Koop B, Birch DG, Bergen AA, Prinsen CF, Polomeno RC, Gal A, Drack AV, Musarella MA, Jacobson SG, Young RS, Weleber RG. Mutations in NYX, encoding the leucine-rich proteoglycan nyctalopin, cause X-linked complete congenital stationary night blindness. Nat Genet. 2000 Nov;26(3):319-23. doi: 10.1038/81619. Citation on PubMed
  • Jacobi FK, Andreasson S, Langrova H, Meindl A, Zrenner E, Apfelstedt-Sylla E, Pusch CM. Phenotypic expression of the complete type of X-linked congenital stationary night blindness in patients with different mutations in the NYX gene. Graefes Arch Clin Exp Ophthalmol. 2002 Oct;240(10):822-8. doi: 10.1007/s00417-002-0562-z. Epub 2002 Sep 21. Citation on PubMed
  • Leroy BP, Budde BS, Wittmer M, De Baere E, Berger W, Zeitz C. A common NYX mutation in Flemish patients with X linked CSNB. Br J Ophthalmol. 2009 May;93(5):692-6. doi: 10.1136/bjo.2008.143727. Epub 2008 Jul 10. Citation on PubMed
  • Morgans CW, Ren G, Akileswaran L. Localization of nyctalopin in the mammalian retina. Eur J Neurosci. 2006 Mar;23(5):1163-71. doi: 10.1111/j.1460-9568.2006.04647.x. Citation on PubMed
  • O'Connor E, Eisenhaber B, Dalley J, Wang T, Missen C, Bulleid N, Bishop PN, Trump D. Species specific membrane anchoring of nyctalopin, a small leucine-rich repeat protein. Hum Mol Genet. 2005 Jul 1;14(13):1877-87. doi: 10.1093/hmg/ddi194. Epub 2005 May 19. Citation on PubMed
  • Poopalasundaram S, Erskine L, Cheetham ME, Hardcastle AJ. Focus on molecules: nyctalopin. Exp Eye Res. 2005 Dec;81(6):627-8. doi: 10.1016/j.exer.2005.07.017. Epub 2005 Sep 12. No abstract available. Citation on PubMed
  • Pusch CM, Zeitz C, Brandau O, Pesch K, Achatz H, Feil S, Scharfe C, Maurer J, Jacobi FK, Pinckers A, Andreasson S, Hardcastle A, Wissinger B, Berger W, Meindl A. The complete form of X-linked congenital stationary night blindness is caused by mutations in a gene encoding a leucine-rich repeat protein. Nat Genet. 2000 Nov;26(3):324-7. doi: 10.1038/81627. Citation on PubMed
  • Xiao X, Jia X, Guo X, Li S, Yang Z, Zhang Q. CSNB1 in Chinese families associated with novel mutations in NYX. J Hum Genet. 2006;51(7):634-40. doi: 10.1007/s10038-006-0406-5. Epub 2006 May 3. Citation on PubMed
  • Zeitz C, Scherthan H, Freier S, Feil S, Suckow V, Schweiger S, Berger W. NYX (nyctalopin on chromosome X), the gene mutated in congenital stationary night blindness, encodes a cell surface protein. Invest Ophthalmol Vis Sci. 2003 Oct;44(10):4184-91. doi: 10.1167/iovs.03-0251. Citation on PubMed
  • Zhang Q, Xiao X, Li S, Jia X, Yang Z, Huang S, Caruso RC, Guan T, Sergeev Y, Guo X, Hejtmancik JF. Mutations in NYX of individuals with high myopia, but without night blindness. Mol Vis. 2007 Mar 1;13:330-6. Citation on PubMed or Free article on PubMed Central

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.