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NYX gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

NYX gene

The NYX gene provides instructions for making nyctalopin, a protein critical for transmitting visual signals from the retina to the brain.

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 cells called bipolar cells, which relay signals to other retinal cells. The retina contains two types of photoreceptors: rods (needed for vision in low light) and cones (needed for vision in bright light, including color vision). Studies suggest the protein helps relay visual signals from rods and cones to bipolar cells, 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

Variants in the NYX gene have been identified in people with X-linked congenital stationary night blindness. NYX gene variants are responsible for the complete form of the disorder, which is characterized by:

  • Difficulty seeing in low light (night blindness)
  • Loss of sharpness (reduced visual acuity)
  • Severe nearsightedness (high myopia)
  • Involuntary movements of the eyes (nystagmus)
  • Eyes that do not look in the same direction (strabismus)

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

Other disorders

Variants in the NYX gene have been found to cause high myopia without the other vision problems that are characteristic of X-linked congenital stationary night blindness. The variants responsible for high myopia each change a single amino acid in nyctalopin, which produces an unstable protein and leads to vision problems.

Other Names for This Gene

  • CLRP
  • NYX_HUMAN

Frequently Asked Questions

Diagnosis combines a detailed history of night‑time visual difficulty with a full ophthalmic exam. Electroretinography (ERG) shows a markedly reduced scotopic (rod) response while photopic (cone) responses are relatively preserved. Genetic testing—either a targeted NYX sequencing panel or whole‑exome sequencing—confirms pathogenic variants.
NYX is X‑linked recessive. A carrier mother has a 50 % chance of passing the mutated X chromosome to each child. Sons who inherit the mutated X will be affected (50 % risk), while daughters who inherit it will become carriers (50 % risk) but usually have normal vision.
There is no cure, but several strategies help: high‑contrast, large‑print reading materials; tinted glasses that reduce glare; and the use of bright, well‑lit environments for tasks performed after dark. Low‑vision specialists may prescribe optical devices (e.g., binoculars with night‑vision filters) that enhance residual rod function.
By definition, CSNB is non‑progressive; the visual deficit is present from early childhood and typically remains stable. However, secondary ocular issues such as high myopia or strabismus can develop and may require separate management.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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