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RPGR gene

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

RPGR gene

The RPGR gene is essential for normal vision, as it helps transport proteins within the cilia of photoreceptor cells; mutations in this gene are a primary cause of X-linked retinitis pigmentosa.

Normal Function

The RPGR gene provides instructions for making a protein that is essential for normal vision. Studies suggest that this protein plays an important role in cell structures called cilia. Cilia are finger-like projections that are found on the surface of cells. They have many different functions. Motile cilia are involved in cell movement, while non-motile or primary cilia are necessary for the perception of sensory input, including hearing, smell, and vision.

The specialized light receptor cells (photoreceptors) in the layer of light-sensitive tissue at the back of the eye are made up of an inner and outer segment. A single cilium (known as a connecting cilium) acts as a bridge between these segments that allows proteins to travel back and forth. Within the connecting cilium, the RPGR protein helps sort and transport other proteins along the cilium between the inner and outer segments of the photoreceptor cells. This transport of proteins is essential to maintain the structure and function of photoreceptor cells.

Health Conditions Related to Genetic Changes

Retinitis pigmentosa

Genetic changes that cause disease are called pathogenic variants. Pathogenic variants in the RPGR gene can cause retinitis pigmentosa, which is characterized by vision loss that worsens over time. Retinitis pigmentosa affects the retina. RPGR gene variants account for 70 to 90 percent of all cases of retinitis pigmentosa with an X-linked pattern of inheritance.

Most of the RPGR gene variants that are responsible for X-linked retinitis pigmentosa occur in the ORF15 exon segment of the RPGR protein. These pathogenic variants cause cells to make a version of the RPGR protein that does not function properly. As a result, the protein’s ability to interact with other molecules is impaired, which disrupts the transport of proteins within the photoreceptor cells. This leads to the gradual loss of photoreceptor cells and the resulting vision loss seen in people with retinitis pigmentosa.

Other disorders

Rarely, pathogenic variants in the RPGR gene have been reported in people with retinitis pigmentosa who have signs and symptoms that affect parts of the body other than the eyes. Along with vision loss, affected individuals can have chronic sinus and respiratory infections, recurrent ear infections (otitis media), and hearing loss (deafness). This collection of features is sometimes called primary ciliary dyskinesia-retinitis pigmentosa syndrome or RPSRDF.

It is unclear why pathogenic variants in the RPGR gene cause a variety of disorders. Studies suggest that certain variants may disrupt the function of cilia in multiple tissues, including the inner ear and respiratory tract. Malfunctioning cilia in these tissues may lead to the hearing loss and respiratory abnormalities seen in some affected individuals.

Other Names for This Gene

  • COD1
  • cone dystrophy 1 (X-linked)
  • CORDX1
  • CRD
  • retinitis pigmentosa 15
  • retinitis pigmentosa 3 GTPase regulator
  • RP15
  • RP3

Frequently Asked Questions

Testing usually involves a blood draw or saliva sample sent to a certified laboratory that sequences the RPGR coding regions and intron‑flanking areas. Results are reported as “pathogenic,” “likely pathogenic,” “variant of uncertain significance (VUS),” or “benign.” A pathogenic or likely pathogenic result confirms the molecular diagnosis and guides prognosis, surveillance (e.g., regular visual field testing), family counseling, and eligibility for clinical trials. If a VUS is returned, further testing (e.g., segregation analysis in family members) or functional studies may be needed before it can influence management. Genetic counseling before and after testing is strongly recommended.
RPGR is located on the X chromosome. A mother who carries one pathogenic RPGR variant has a 50 % chance of passing the mutated X to each child. Sons who inherit the mutated X will be affected because they have only one X chromosome. Daughters who inherit the mutated X become carriers; they usually have no symptoms but can develop mild retinal changes and have a 50 % chance of passing the mutation to each of their own children. A father with an RPGR mutation cannot pass it to his sons (they receive his Y chromosome) but will transmit the mutated X to all of his daughters, making them carriers.
The first signs often appear in late childhood or early adulthood and include night‑time vision loss (nyctalopia), difficulty adapting to low‑light environments, and a gradual narrowing of peripheral (side) vision that may be noticed as bumping into objects. Some patients also report subtle color‑vision changes or increased glare. If any of these symptoms arise, especially with a known family history, a dilated retinal exam with electroretinography can detect early RPGR‑related changes.
s of 2024, an adeno‑associated virus (AAV)–based gene‑replacement therapy (voretigene neparvovec) is approved for RPE65‑related disease, but RPGR‑specific gene therapy is still investigational. Multiple phase I/II trials are recruiting patients with confirmed pathogenic RPGR variants, typically requiring measurable visual field loss but retained central vision (better than 20/200). Eligibility criteria include age ≥ 18 years, documented genetic confirmation, and specific retinal imaging findings. You can locate active trials on clinicaltrials.gov or through a retinal genetics specialist, who can also help with trial enrollment and insurance considerations.
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.