Unilateral pigmentary retinopathy: a retrospective case series

DIAGNOSTIC YIELD OF AN INHERITED RETINAL DISEASE GENE PANEL IN RETINOPATHY OF UNKNOWN ORIGIN

PURPOSE

Evaluating the presence of class 3, 4, and 5 genetic variants in inherited retinal disease (IRD) genes in patients with retinopathy of unknown origin (RUO).

METHODS

Multicentric retrospective study of RUO cases diagnosed between January 2012 and February 2022. General and ophthalmologic history, complete ophthalmologic examination, antiretinal antibodies, and IRD gene panel results were analyzed in every patient. Four RUO categories were defined: nonparaneoplastic autoimmune retinopathy, unilateral pigmentary retinopathy, asymmetrical pigmentary retinopathy, and acute zonal occult outer retinopathy.

RESULTS

The authors included 12 patients (9 females) across these four RUO categories. Mean age at inclusion was 45.6 years (20-68 years). Seven patients demonstrated class 3 variants in IRD genes. Of these, two also demonstrated class 5 variants in other IRD genes. The remaining five patients had negative panel results. IRD gene panel analysis allowed diagnosis refinement in 1 (8.3%) nonparaneoplastic autoimmune retinopathy patient in the RUO cohort. When considering the nonparaneoplastic autoimmune retinopathy subpopulation only, a higher diagnostic yield of 20% (1/5 patients) was achieved.

CONCLUSION

Every suspected nonparaneoplastic autoimmune retinopathy patient should benefit from gene panel testing to not overlook undiagnosed IRDs. By contrast, unilateral pigmentary retinopathy, asymmetrical pigmentary retinopathy, and acute zonal occult outer retinopathy subpopulations did not benefit from genetic testing in this study.

Pigmentary retinal dystrophy associated with peroxisome biogenesis disorder-Zellweger syndrome spectrum

Pigmentary retinal dystrophy (PRD) is a group of inherited disorders involving the progressive degeneration of rod and cone photoreceptors and the retinal pigment epithelium (RPE), which can progress to pigmentary retinopathy (PR). We present a case of PRD in a female pediatric patient who has pathogenic variants in the PRPH2 and PEX1 genes. The patient has associated macular edema and secondary visual impairment. Treatment has included serial dexamethasone intravitreal implant injections and topical dorzolamide. The PEX1 gene mutation is associated with peroxisome biogenesis disorder-Zellweger syndrome spectrum (PBD-ZSS) and resulting retinal dystrophies. The PRPH2 mutation may play a role in macular edema and PRD, as it is implicated in macular degeneration, choroid defects, and photoreceptor dysfunction. In this case, we review multiple gene mutations playing potential etiologic roles for PRD and discuss care management.

Two cases of unilateral cone-rod dysfunction presenting in adult females

PURPOSE

To describe cases of unilateral cone-rod dysfunction presenting in two middle-aged females.

METHODS

This case series highlights two middle-aged female patients with progressive visual decline in one eye. Fundus photography, fundus autofluorescence (FAF), spectral-domain optical coherence tomography (SD-OCT), multi-focal electroretinogram (mfERG), full-field electroretinogram(ffERG), and genetic testing were obtained.

RESULTS

In the first patient, mfERG showed an extinguished response and ffERG demonstrated markedly reduced a-wave and b-wave amplitudes (more pronounced under photopic conditions) in the right eye. SD-OCT showed attenuation of the ellipsoid zone of the right eye. Similar findings were appreciated in the second patient. Genetic testing in the first patient identified three heterozygous variants in PRPH2, RCBTB1, and USH2A. The second patient was found to have heterozygous variants in BBS1 and ABCA4.

CONCLUSION

These two cases add to the literature of case reports of unilateral cone-rod and rod-cone dystrophies. However, the underlying etiology of the unilateral pattern of cone-rod dysfunction and the significance of the heterozygous mutations found in both cases remains uncertain.

Unilateral Retinitis Pigmentosa Associated with Possible Ciliopathy and a Novel Mutation

Unilateral retinitis pigmentosa (URP) is a rare retinal dystrophy. We describe the clinical course of two patients with (URP) unilateral retinitis pigmentosa confirmed by genetic testing, indicating ciliary dysfunction. Methods: The methods used in this study included a detailed ophthalmic examination, multimodal retinal imaging, Goldmann visual fields, full-field electroretinography (ffERG) and targeted next-generation sequencing. Results: A 32-year-old female (patient 1) and 65-year-old male (patient 2) were found to have URP. ffERG showed a non-recordable response in the affected eye and a response within normal limits in the fellow eye of patient 1, while patient 2 showed non-recordable responses in the apparently unaffected eye and a profound reduction in the photopic and scotopic responses in the affected eye. Next-generation sequencing revealed novel compound heterozygous c.373 C>T (p.Arg125Trp) and c.730-22_730-19dup variants in AGBL5 in patient 1, and a novel hemizygous c.1286 C>T (p.Pro429Leu) in patient 2; both gene mutations were 0%. Segregation analysis was not possible for either of the mutations. Conclusion: This report expands the clinical and molecular genetic spectrum of URP.

[Asymmetric form of pigmentary retinopathy (case study)]

Unilateral pigmentary retinopathy (PR) is a rare, atypical form of hereditary retinal pathology. Different types of secondary retinopathy associated with various non-hereditary diseases, trauma or intoxication can imitate unilateral PR. Therefore, it is important to determine the cause of visual disorders and differentiate between unilateral and asymmetric PR. The article presents an example of using modern structural and functional diagnostic methods that helped diagnose the asymmetric form of the disease in a patient with suspected unilateral PR.

Quantitative assessment of visual pathway function in blind retinitis pigmentosa patients

OBJECTIVE

The current methods used to assess visual function in blind retinitis pigmentosa (RP) patients are mostly subjective. We aimed to identify effective, objective methods.

METHODS

We enrolled patients diagnosed with blindness associated with RP; we finally selected 26 patients (51 eyes) with a visual field radius less than 10 degrees and divided them into the following 4 groups by best-corrected visual acuity (BCVA): group 1, no light perception (NLP, 4 eyes); group 2, light perception (LP, 12 eyes); group 3, hand movement or finger counting (faint form perception, FFP, 22 eyes); and group 4, BCVA from 0.1 to 0.8 (form perception, FP, 13 eyes). All patients underwent optometry, optical coherence tomography (OCT), color fundus photography, fundus autofluorescence (FAF), full field electroretinography (ffERG), pattern electroretinography (PERG), multifocal electroretinography (mf-ERG), pattern visual evoked potential (PVEP), flash visual evoked potential (FVEP), and pupillary light response (PLR) assessments. Five patients in groups 1, 2, and 3 (1, 2, and 2 subjects, respectively) underwent functional magnetic resonance imaging (fMRI) scans and were compared with five healthy subjects.

RESULTS

The outer plexiform layer was thinner in group 1, and the outer nuclear layer was thinner in groups 1 and 2. The ffERG, PERG, and mf-ERG findings were unrecordable in all four groups. The P2 amplitude of the FVEP was significantly lower in groups 1 and 2, while the P100 amplitude of the PVEP was higher in groups 2, 3 and 4 than in group 1. After white- and blue-light stimuli, the PLR thresholds in the patients without form perception were significantly higher. The threshold of the PLR stimulated by blue and white light was negatively correlated with the amplitudes of P2 and P100. Moreover, the fMRI findings showed that some RP patients have significant visual cortex activation in response to certain types of stimulation. However, statistical analysis was not performed because of the small number of cases.

CONCLUSIONS

OCT, VEP, PLR and fMRI assessments can evaluate residual visual pathway function in blind RP patients.

SIGNIFICANCE

Our study may have clinical significance for the potential prediction of RP patient prognoses and the effects after clinical trials.

Vascular abnormalities in uveitis

Inflammation can involve several ocular structures, including the sclera, retina, and uvea, and cause vascular changes in these tissues. Although retinal vasculitis is the most common finding associated with uveitis involving the posterior segment, other vascular abnormalities may be seen in the retina. These include capillary nonperfusion and ischemia, vascular occlusions, preretinal neovascularization, microaneurysms and macroaneurysms, and telangiectasia. Moreover, vasoproliferative tumors and subsequent coat-like response can develop secondary to uveitis. Fluorescein angiography is ideal for the investigation of retinal vascular leakage and neovascularization, while optical coherence tomography angiography can provide depth resolved images from the superficial and deep capillary plexus and can demonstrate vascular remodeling. Choroidal vascular abnormalities primarily develop in the choriocapillaris or in the choroidal stroma and can appear as flow void in optical coherence tomography angiography and filling defect and vascular leakage in indocyanine green angiography. Extensive choriocapillaris nonperfusion in the presence of choroidal inflammation can increase the risk of choroidal neovascular membrane development. Iris vascular changes may manifest as dilation of vessels in stroma due to inflammation or rubeosis that is usually from ischemia in retinal periphery secondary to chronic inflammation. More severe forms of scleral inflammation, such as necrotizing scleritis, are associated with vascular occlusion in the deep episcleral plexus, which can lead to necrosis of sclera layer and uveal exposure.

Evaluation of fluocinolone acetonide 0.19 mg intravitreal implant in the management of birdshot retinochoroiditis

PURPOSE

To report treatment outcomes and efficacy of the fluocinolone acetonide 0.19 mg intravitreal implant (Iluvien) in controlling retinal and choroidal inflammation in 11 patients with birdshot retinochoroiditis.

METHODS

A single-centre, retrospective, interventional case series. The primary efficacy end point was improvement in vascular leakage on fluorescein angiography (FA), effect on cystoid macular oedema (CMO) and resolution of hypofluorescent lesions on indocyanine green angiography (ICGA); secondary measures were improvements on pattern and full-field electroretinogram (PERG; ERG) parameters. Safety outcome measures were intraocular elevation and cataractogenesis.

RESULTS

Fifteen eyes received Iluvien implant with an average follow-up of 31 months (range 12-36 months). Prior to the implant, 5 (33.3%) eyes had received dexamethasone intravitreal implant 0.7 mg (Ozurdex). FA showed evidence of vascular leakage in all eyes at baseline. Between month 6 and 12, FA showed that 73.4% of eyes had no leakage, this increased to 84.6% by month 24. Three eyes in our study had CMO at baseline. 6 months after Iluvien implant, all eyes achieved complete CMO resolution. One year after insertion of the implant, the characteristic hypofluorescent lesions on ICGA were unchanged in all cases. There was baseline ERG evidence indicating a high incidence of peripheral cone system dysfunction and most showed PERG evidence of macular dysfunction. Retinal function improved and macular function improved or was stable in the majority following treatment.

CONCLUSIONS

The results show the possible therapeutic effect of Iluvien in the management of Birdshot-related vascular leakage, CMO and retinal dysfunction. However, choroidal lesions seem to persist with no detectable response to treatment.

Usher syndrome: diagnostic approach, differential diagnoses and proposal of an updated function-based genetic classification

Usher syndrome (USH) manifests with congenital and apparently isolated hearing loss, followed by retinal degeneration in later life. Therefore, and because of its high prevalence in the congenitally hearing-impaired population, USH is one of the most relevant deafness syndromes. Next-generation sequencing (NGS)-based testing can now provide most analyzed USH patients with a molecular diagnosis, based on mutations in 11 genes. Given the availability of several excellent articles on the clinical and biochemical basis of USH, this short review focuses on critical assessment of new genes announced as USH genes, clinical and genetic differential diagnoses and therapeutic developments. Because obsolete loci, disproved USH genes and the inclusion of genes whose mutations cause similar phenotypes have increasingly blurred genetic classification, a revision based on phenotype restricted to genes related to the Usher protein complex is proposed.

Unilaterally extinguished electroretinograms in an eye with normal visual acuity and visual field

PURPOSE

This study reports a case of unilateral retinopathy with extinguished full-field ERGs (ffERGs), wherein the visual acuity was 16/16 and the visual field was spared.

METHODS

Observational case report.

RESULTS

A 39-year-old female had developed nyctalopia in her left eye. Two years later, she visited an ophthalmologist who noted a bilaterally reduced pigmentation of the fundus. Her best-corrected visual acuity was 16/16 in both the eyes. Goldmann perimetry demonstrated that her visual field was bilaterally fully spared. ffERGs measurement was performed in accordance with the ISCEV standard protocol and indicated that her right eye was normal. However, all ERG responses were severely attenuated in her left eye. Multifocal ERG responses were found to be normal in the right eye and extinguished in the left eye except for residual responses that were exclusively located at the center. During the 7 years of the follow-up period, the visual field in the left eye, which was once normal, became shaded, and the development of a ring scotoma was identified. The visual field in the right eye is still full.

CONCLUSIONS

The pathogenesis of this patient's condition still remains unknown, while unilateral retinitis pigmentosa, unilateral pigmentary retinopathy, acute zonal occult outer retinopathy, and autoimmune retinopathy can all be considered as possible explanations. The uniqueness of this case study is that the extinguished ERG responses are predictive of the functional alteration in the affected eye, when the initial visual acuity and the visual field were normal.