Overview
Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterized by progressive degeneration of rod photoreceptors followed by cone involvement. It is the most common inherited retinal disease, affecting approximately 1 in 4,000 individuals worldwide. RP typically presents with night blindness in childhood or adolescence, progressing to peripheral visual field loss, and eventually central vision impairment in many patients.
Genetics
RP is genetically heterogeneous with over 90 causative genes identified. Inheritance patterns include autosomal dominant (30–40%), autosomal recessive (50–60%), and X-linked (5–15%). Digenic and mitochondrial forms also exist.
| Gene | Locus | Inheritance | Notes |
|---|---|---|---|
| RPGR | Xp11.4 | X-linked | Most common X-linked form; accounts for ~70% of XLRP |
| USH2A | 1q41 | AR | Most common AR gene; also causes Usher syndrome type 2 |
| RHO | 3q22.1 | AD | Rhodopsin; most common AD gene (~25% of ADRP) |
| PRPF31 | 19q13.42 | AD | Pre-mRNA processing factor; variable penetrance |
| RP1 | 8q12.1 | AD/AR | Oxygen-regulated photoreceptor protein |
| CNGB1 | 16q13 | AR | Cyclic nucleotide-gated channel beta-1 |
Clinical Presentation
Early (childhood–adolescence)
- Night blindness (nyctalopia)
- Difficulty adapting to dim light
- Reduced peripheral vision
Mid-stage (young adulthood)
- Progressive peripheral field constriction ('tunnel vision')
- Photopsia (light flashes)
- Difficulty with contrast sensitivity
Late stage
- Severe peripheral field loss
- Central vision loss in some patients
- Legal blindness in ~25% by age 50
Diagnosis
- Electroretinogram (ERG): Reduced or absent rod responses; hallmark diagnostic test
- Visual field testing: Characteristic ring scotoma progressing to tunnel vision
- Fundus examination: Bone-spicule pigmentation, attenuated retinal vessels, waxy disc pallor
- Optical coherence tomography (OCT): Photoreceptor layer thinning
- Genetic testing: Next-generation sequencing panels for 90+ RP genes
- Fundus autofluorescence (FAF): Hyperautofluorescent ring indicating transition zone
Current Research & Treatment
Gene therapy approaches are in active clinical development for multiple RP subtypes. RPGR-targeted AAV gene therapy has shown promising results in Phase 1/2 trials. Antisense oligonucleotide therapy for PRPF31 mutations and optogenetics-based approaches for end-stage RP are also under investigation. The Foundation Fighting Blindness funds numerous active trials.
Active Clinical Trials
The following active clinical trials are investigating treatments for Retinitis Pigmentosa. Trial status and enrollment may change; always verify directly on ClinicalTrials.gov.
Ocugen · Modifier gene therapy (NR2E3)
SparingVision · AAV neuroprotective (gene-agnostic)
Beacon Therapeutics · AAV gene therapy (RPGR / XLRP)
BlueRock Therapeutics · iPSC-derived photoreceptor cell therapy
Johns Hopkins University · Oral antioxidant (gene-agnostic)
Kiora Pharmaceuticals · Molecular photoswitch optogenetics
Supporting Organizations
The following nonprofit organizations fund research, support patients, and advocate for advances in the treatment and cure of Retinitis Pigmentosa.
Foundation Fighting Blindness
VisitThe world's leading funder of IRD research since 1971.
$954M+ raised since 1971Retinal Degeneration Fund (RD Fund)
VisitBridging nonprofit research and commercial IRD therapy development.
$86M deployed in 17 companiesResearch to Prevent Blindness (RPB)
VisitThe leading nonprofit supporting all forms of eye disease research.
$400M+ in total research fundingA Race Against Blindness
VisitFunding sight-saving clinical trials to treat childhood blindness.
$5.1M+ granted to BBS1 gene therapyRetina International
VisitA patient-led global umbrella NGO for retinal disease communities worldwide.
34+ national societies worldwidePrevent Blindness
VisitThe nation's leading volunteer eye health and safety organization since 1908.
115+ years of vision health advocacyFighting Blindness Canada
VisitLeading the fight against blindness by funding IRD research in Canada.
Canada's leading IRD research funderRetina UK
VisitFunding research and supporting people affected by inherited sight loss in the UK.
UK's leading inherited sight loss charityFighting Blindness Ireland
VisitDriving IRD research and supporting patients in Ireland.
Target 5000: Ireland's national IRD registry