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RGS9BP gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

RGS9BP gene

The RGS9BP gene provides instructions for a protein that anchors RGS9 in the retina, playing a critical role in how the eye recovers after light exposure.

Normal Function

The RGS9BP gene (which is also known as R9AP) provides instructions for making a protein called RGS9 binding protein. This protein is found in the retina, which is the specialized tissue at the back of the eye that detects light and color. Within the retina, the protein is associated with light-detecting cells called photoreceptors. As its name suggests, RGS9 binding protein interacts with a protein called RGS9. It anchors the RGS9 protein to photoreceptors and stimulates RGS9's activity.

When light enters the eye, it stimulates specialized pigments in photoreceptor cells, triggering a series of chemical reactions that produce an electrical signal interpreted by the brain as vision (phototransduction). Once photoreceptors have been stimulated by light, they must return to their resting state before they can be stimulated again. RGS9 and RGS9 binding protein are involved in a chemical reaction that helps return photoreceptors to their resting state quickly after light exposure.

Health Conditions Related to Genetic Changes

Bradyopsia

At least six mutations in the RGS9BP gene have been found to cause bradyopsia, a rare condition that affects vision. In people with bradyopsia, the eyes adapt more slowly than usual to changing light conditions. Some affected individuals also have difficulty seeing small moving objects.

The RGS9BP gene mutations that cause bradyopsia prevent RGS9 binding protein from anchoring the RGS9 protein to photoreceptor cells. The resulting loss of RGS9 protein function prevents photoreceptors from recovering quickly after responding to light. Normally they return to their resting state in a fraction of a second, but in people with RGS9BP gene mutations, it can take ten seconds or longer. During that time, the photoreceptors cannot respond to light. This delay causes temporary blindness in response to changing light conditions and may interfere with seeing small objects when they are in motion.

Other Names for This Gene

  • FLJ45744
  • R9AP
  • regulator of G-protein signaling 9 binding protein
  • regulator of G-protein signaling 9-binding protein
  • RGS9 anchor protein
  • RGS9-anchoring protein

Frequently Asked Questions

Most reported RGS9BP mutations follow an autosomal recessive inheritance pattern: both copies of the gene must be altered for disease to appear. Parents who each carry one defective copy are typically asymptomatic. If both parents are carriers, each child has a 25 % chance of being affected, a 50 % chance of being a carrier, and a 25 % chance of having two normal copies. Carrier testing for siblings and prenatal or pre‑implantation testing for future pregnancies can be discussed with a genetic counselor.
Bradyopsia results from mutations in the RGS9BP gene that impair the RGS9‑binding protein. Without this anchor, the RGS9 enzyme cannot efficiently shut off the phototransduction cascade, so photoreceptor cells stay “activated” longer after light exposure. The delayed de‑activation means the retina needs extra time to return to its resting state, causing slow adaptation to changes in illumination.
Yes. A targeted DNA test that sequences the RGS9BP gene can identify known pathogenic variants (including the six most common mutations linked to bradyopsia). Testing is usually ordered by an ophthalmologist or medical geneticist and may be combined with a broader retinal dystrophy panel if the diagnosis is unclear.
Practical strategies include: (1) using tinted glasses or transition lenses to reduce glare when moving between lighting conditions; (2) allowing a few minutes for eyes to adjust before performing tasks that require fine visual detail; (3) keeping indoor lighting consistent and avoiding sudden bright flashes; and (4) employing high‑contrast, larger‑print materials for reading. Low‑vision rehabilitation services can provide customized visual aids and training.
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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