Retinitis pigmentosa is a common genetic disease that causes retinal degeneration and blindness for which there is currently no curable treatment available. Vision preservation was observed in retinitis pigmentosa animal models after retinal stem cell transplantation. However, long-term safety studies and visual assessment have not been thoroughly tested in retinitis pigmentosa patients. In our pre-clinical study, purified human fetal-derived retinal progenitor cells (RPCs) were transplanted into the diseased retina of Royal College of Surgeons (RCS) rats, a model of retinal degeneration. Based on these results, we conducted a phase I clinical trial to establish the safety and tolerability of transplantation of RPCs in eight patients with advanced retinitis pigmentosa. Patients were studied for 24 months. After RPC transplantation in RCS rats, we observed moderate recovery of vision and maintenance of the outer nuclear layer thickness. Most importantly, we did not find tumor formation or immune rejection. In the retinis pigmentosa patients given RPC injections, we also did not observe immunological rejection or tumorigenesis when immunosuppressive agents were not administered. We observed a significant improvement in visual acuity (P < 0.05) in five patients and an increase in retinal sensitivity of pupillary responses in three of the eight patients between 2 and 6 months after the transplant, but this improvement did not appear by 12 months. Our study for the first time confirmed the long-term safety and feasibility of vision repair by stem cell therapy in patients blinded by retinitis pigmentosa. WHO Trial Registration, ChiCTR-TNRC-08000193 . Retrospectively registered on 5 December 2008.

Background: To report the prevalence of ocular abnormalities and investigate visual acuity in a large cohort of retinitis pigmentosa (RP) patients in Western China.Methods: The medical records and ophthalmic examination reports of 2127 eyes of 1065 RP patients at one eye hospital were retrospectively reviewed to determined the prevalence of ocular abnormalities and the relationship between best corrected visual acuity (BCVA) and macular abnormalities.Results: Nyctalopia (58.2%) and blurred vision (27.1%) were the leading reasons for RP patients to request an ophthalmic examination. BCVA measurements in the better eyes at first clinical presentation showed that 304 patients (28.5%) were categorised as blind and 220 patients (20.7%) as low vision. The most common ocular abnormalities were macular abnormalities (59.7%) and cataracts (43.1%). The macular abnormalities included epiretinal membranes (51.1%), cystoid macular edema (18.4%), vitreomacular traction syndrome (2.4%), macular holes (2.3%) and choroidal neovascular membranes (0.05%). Glaucoma was found in 35 eyes (1.6%). The proportions of epiretinal membranes (p = 0.001) and macular holes (p = 0.008) increased significantly with age. Cystoid macular edema was significantly associated with poorer visual acuity in RP patients with clear lens (p = 0.002).Conclusion: Cataracts and macular abnormalities are common in RP patients. Of the macular abnormalities, cystoid macular edema may have a negative effect on BCVA in RP patients with clear lens. Therefore, optical coherence tomography screening in RP patients is highly recommended for early detection and treatment of maculopathy.

Purpose . To delineate the clinical and genetic characteristics of Chinese patients with RPGRIP1 ‐associated Leber congenital amaurosis 6 (LCA6). Methods . After screening 352 unrelated families with clinically diagnosed RP, five LCA6 patients with RPGRIP1 variations from unrelated Chinese families were identified. Full ophthalmology examinations, including decimal best‐corrected visual acuity (BCVA), fundus photography, fundus autofluorescence imaging, spectral‐domain optical coherence tomography (SD‐OCT), full‐field electroretinography (ffERG), multifocal electroretinography (mfERG), perimetry, and flash visual evoked potential (FVEP), were performed. Target next‐generation sequencing (NGS) and Sanger sequencing were performed for the five patients to identify and to validate candidate disease‐causing variants. Results . Five patients were molecularly diagnosed as the LCA6 associated with RPGRIP1 variation, with typical clinical characteristics including congenital night blindness, nystagmus, and visual defect, at an early age. Interestingly, LCA6 exhibited extensive clinical heterogeneity and the changes in the morphology and function were not completely consistent in the five LCA6 patients. Case 1 showed extensive inferior‐nasal retinal atrophy with a corresponding area of hypofluorescence in fundus autofluorescence, and the fundus photograph was nearly normal in cases 2 and 3. The ERG results displayed a moderately reduced rod‐system response in cases 1 and 2 and a significant reduced rod‐system response in case 3. Both case 4 and case 5 showed mottled pigmentation in fundi and an unrecordable rod and cone‐system response in ERG. Moreover, we identified eight compound variants and one homozygous variant in the five patients with RPGRIP1 . Conclusions . This is the largest report focused on the clinical electrophysiological features of patients with associated LCA6 caused by the variation in the RPGRIP1 gene in the Chinese population with an enriched phenotypic and genotypic background of LCA6 to improve future gene therapies.

Background: The USH2A gene encodes usherin, a basement membrane protein that is involved in the development and homeostasis of the inner ear and retina. Mutations in USH2A are linked to Usher syndrome type II (USH II) and non-syndromic retinitis pigmentosa (RP). Molecular diagnosis can provide insight into the pathogenesis of these diseases, facilitate clinical diagnosis, and identify individuals who can most benefit from gene or cell replacement therapy. Here, we report 21 pathogenic mutations in the USH2A gene identified in 11 Chinese families by using the targeted next-generation sequencing (NGS) technology. Methods: In all, 11 unrelated Chinese families were enrolled, and NGS was performed to identify mutations in the USH2A gene. Variant analysis, Sanger validation, and segregation tests were utilized to validate the disease-causing mutations in these families. Results: We identified 21 pathogenic mutations, of which 13, including 5 associated with non-syndromic RP and 8 with USH II, have not been previously reported. The novel variants segregated with disease phenotype in the affected families and were absent from the control subjects. In general, visual impairment and retinopathy were consistent between the USH II and non-syndromic RP patients with USH2A mutations. Conclusions: These findings provide a basis for investigating genotype–phenotype relationships in Chinese USH II and RP patients and for clarifying the pathophysiology and molecular mechanisms of the diseases associated with USH2A mutations.

Occult Macular Dystrophy (OMD), primarily caused by retinitis pigmentosa 1-like 1 (RP1L1) variants, is a complex retinal disease characterised by progressive vision loss and a normal fundus appearance. This study aims to investigate the diverse phenotypic expressions and genotypic correlations of OMD in Chinese patients, including a rare case of Vitelliform Macular Dystrophy (VMD) associated with RP1L1. We analysed seven OMD patients and one VMD patient, all with heterozygous pathogenic RP1L1 variants. Clinical assessments included Best Corrected Visual Acuity (BCVA), visual field testing, Spectral Domain Optical Coherence Tomography (SD-OCT), multifocal Electroretinograms (mfERGs), and microperimetry. Next-generation sequencing was utilised for genetic analysis. The OMD patients displayed a range of phenotypic variability. Most (5 out of 7) had the RP1L1 variant c.133 C > T; p.R45W, associated with central vision loss and specific patterns in SD-OCT and mfERG. Two patients exhibited different RP1L1 variants (c.3599G > T; p.G1200V and c.2880G > C; p.W960C), presenting milder phenotypes. SD-OCT revealed photoreceptor layer changes, with most patients showing decreased mfERG responses in the central rings. Interestingly, a unique case of VMD linked to the RP1L1 variant was observed, distinct from traditional OMD presentations. This study highlights the phenotypic diversity within OMD and the broader spectrum of RP1L1-associated macular dystrophies, including a novel association with VMD. The findings emphasise the complexity of RP1L1 variants in determining clinical manifestations, underscoring the need for comprehensive genetic and clinical evaluations in macular dystrophies.