Ultra-widefield fundus autofluorescence patterns in retinitis pigmentosa and other retinal dystrophies

Using Multimodal Imaging to Refine the Phenotype of PRPH2-associated Retinal Degeneration

OBJECTIVE

To refine retinal peripherin-2 (PRPH2)-associated retinal degeneration (PARD) phenotypes using multimodal imaging.

DESIGN

Retrospective review of clinical records and multimodal imaging.

SUBJECTS

Patients who visited the inherited retinal degeneration (IRD) clinic at 2 tertiary referral eye centers with molecularly confirmed IRD due to PRPH2 variants.

METHODS

Retinal imaging was reviewed using ultrawidefield (UWF) pseudocolor, UWF fundus autofluorescence, and spectral-domain OCT. Phenotypes were identified in the macular or peripheral region. A combined phenotype was considered if any phenotypes were present in both macular and peripheral regions. Mixed phenotypes in the macula or peripheral retina were considered if there were 2 distinct phenotypes identified in the same eye. The presence or absence of atrophy in the macular or peripheral area was also noted.

MAIN OUTCOME MEASURE

Grading of multimodal imaging by phenotype and atrophy.

RESULTS

A total of 144 eyes of 72 patients were included in this study. The majority of the eyes had combined macular and peripheral phenotypes (89/144, 61.8%), whereas 44 (30.6%) eyes had isolated macular findings, and 11 (7.6%) had isolated peripheral findings. Twenty-five eyes were classified with mixed macular phenotypes, whereas fundus flavimaculatus dystrophy type was the most common combined macular and peripheral phenotype (54/144, 37.5%): n = 10 with macular dystrophy and macular flavimaculatus dystrophy (MFD), and n = 15 with butterfly pattern dystrophy and MFD. Nearly half of the eyes (71/144, 49.3%) were identified to have concomitant outer retinal atrophy. Fundus flavimaculatus type dystrophy was also associated with the highest proportion of concomitant atrophy (57/71, 80.3%).

CONCLUSIONS

Peripherin-2-associated retinal degeneration demonstrates a wide array of phenotypes using multimodal imaging. We report that combinations of classically described phenotypes were often seen. Additionally, macular and peripheral atrophy were often associated with PARD phenotypes. Refinement of PARD phenotypes using newer multimodal imaging techniques will likely assist diagnosis and future clinical trials.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Oxidative Stress and Inflammation-Related mRNAs Are Elevated in Serum of a Finnish Wet AMD Cohort

Purpose

Localized diseases can be affected by and affect the systemic environment via blood circulation. In this study, we explored the differences in circulating serum mRNAs between patients with wet AMD (wAMD) and controls.

Methods

Blood samples were obtained from 60 Finnish patients with wAMD and 64 controls. After serum preparation and RNA sequencing, the count data was examined for differentially expressed genes (DEGs) and further checked for enriched molecular pathways and ontology terms as well as links to clinical data.

Results

We found many DEGs and some enriched pathways, including the inflammation and cell survival-associated pathway tumour necrosis factor alpha (TNF-α) signaling via nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). The related DEGs were oxidized low-density lipoprotein receptor 1 (OLR1), salt inducible kinase 1 (SIK1), and coagulation factor III (F3). DEGs from degradative macular and retinal processes were also examined, many of which were also related to cardiovascular disease and maintenance. Additionally, DEG counts were inspected in relation to clinical and anti-VEGF treatment parameters, and glutamine amidotransferase-like class 1 domain-containing 3A (GATD3A) levels were found to be significantly lower in patients with wAMD treated with anti-VEGF.

Conclusions

Differentially expressed systemic mRNAs that are linked to mitochondrial function, oxidative stress, and inflammation may have a role in the pathology of wAMD. Our observations provide new data for the understanding of the progression of wAMD.

Clinical and Genetic Findings in a Cohort of Patients with PRPF31-Associated Retinal Dystrophy

PURPOSE

The purpose of our study was to assess the phenotypic and genotypic spectrum in a large cohort of patients with PRPF31-associated retinal dystrophy.

DESIGN

Retrospective cohort study.

METHODS

In this retrospective chart review study, we collected cross-sectional data on the phenotype and genotype of patients with PRPF31-associated retinal dystrophy from the clinics for inherited retinal dystrophies at the University of Tuebingen and the local RetDis database and biobank. Patients underwent thorough ophthalmological examinations and genetic testing.

RESULTS

Eighty-six patients from 61 families were available for clinical assessment, while genomic DNA was available for 111 individuals (index patients and family members). Fifty-three different disease-associated variants were observed in our cohort. Point mutations were the most common class. All but two patients exhibited features of a typical Retinitis pigmentosa (RP). One patient showed a cone-rod dystrophy pattern. One mutation carrier revealed no signs of a retinal dystrophy. There was a statistically significant better visual acuity for patients with large deletions in the 20-39 age group. Cystoid macular edema was common in those with preserved central retina and showed an association with female sex.

CONCLUSION

Our study confirms high phenotypic variability in disease onset and age at which legal blindness is reached in PRPF31-associated RP. Non-penetrance is commonly documented in family history, although poorly represented in our study, possibly indicating that true asymptomatic mutation carriers are rare if followed-up over lifetime with thorough ophthalmologic workup.

The New Era of Therapeutic Strategies for the Management of Retinitis Pigmentosa: A Narrative Review of the Pathomolecular Mechanism for Gene Therapies

Retinitis pigmentosa, or RP, is a group of inherited retinal degenerations involving progressive loss of photoreceptor cells- rods and cones- ultimately causing severe vision loss and blindness. RP, although a very common ailment, continues to be an incurable disease with little to be done medically. However, with the breakthroughs in gene therapy and stem cell transplantation in recent years, a new door has been opened to the treatment of RP. This narrative review summarizes the pathomolecular mechanisms of RP, focusing on the genetic and molecular abnormalities that lead to the process of retinal degeneration. In this section, we talk about the current theories of how RP develops, gene mutations, oxidative stress, and inflammation. We also delve into new therapeutic approaches such as gene therapy, stem cell transplantation and genome surgery, which are designed to either replace or repair the damaged photoreceptors to restore vision and ultimately enhance the life of the RP patient. Another topic covered is the obstacles and research frontiers of these revolutionary treatments. This article is intended to give a complete overview of the molecular processes of RP and the promising treatment strategies that could change the way this devastating disease is treated.

Retinal Degeneration Associated With RPGRIP1: A Review of Natural History, Mutation Spectrum, and Genotype-Phenotype Correlation in 228 Patients

Purpose:RPGRIP1 encodes a ciliary protein expressed in the photoreceptor connecting cilium. Mutations in this gene cause ∼5% of Leber congenital amaurosis (LCA) worldwide, but are also associated with cone–rod dystrophy (CRD) and retinitis pigmentosa (RP) phenotypes. Our purpose was to clinically characterize RPGRIP1 patients from our cohort, collect clinical data of additional RPGRIP1 patients reported previously in the literature, identify common clinical features, and seek genotype–phenotype correlations.

Methods: Clinical data were collected from 16 patients of our cohort and 212 previously reported RPGRIP1 patients and included (when available) family history, best corrected visual acuity (BCVA), refraction, comprehensive ocular examination, optical coherence tomography (OCT) imaging, visual fields (VF), and full-field electroretinography (ffERG).

Results: Out of 228 patients, the majority (197, 86%) were diagnosed with LCA, 18 (7%) with RP, and 13 (5%) with CRD. Age of onset was during early childhood (n = 133, average of 1.7 years). All patients but 6 had moderate hyperopia (n = 59, mean of 4.8D), and average BCVA was 0.06 Snellen (n = 124; only 10 patients had visual acuity [VA] > 0.10 Snellen). On funduscopy, narrowing of blood vessels was noted early in life. Most patients had mild bone spicule-like pigmentation starting in the midperiphery and later encroaching upon the posterior pole. OCT showed thinning of the outer nuclear layer (ONL), while cystoid changes and edema were relatively rare. VF were usually very constricted from early on. ffERG responses were non-detectable in the vast majority of cases. Most of the mutations are predicted to be null (363 alleles), and 93 alleles harbored missense mutations. Missense mutations were identified only in two regions: the RPGR-interacting domain and the C2 domains. Biallelic null mutations are mostly associated with a severe form of the disease, whereas biallelic missense mutations usually cause a milder disease (mostly CRD).

Conclusion: Our results indicate that RPGRIP1 biallelic mutations usually cause severe retinal degeneration at an early age with a cone–rod pattern. However, most of the patients exhibit preservation of some (usually low) BCVA for a long period and can potentially benefit from gene therapy. Missense changes appear only in the conserved domains and are associated with a milder phenotype.

Novel clinical presentation of a CRX rod-cone dystrophy

We describe a novel clinical presentation of a CRX rod-cone dystrophy in a single family. Two boys ages 6 and 12 years presented with clinical and optical coherence tomography features suggestive of X-linked retinoschisis, but with optic nerve swelling without increased intracranial pressure. One patient had an electronegative electroretinogram (ERG) and the other had rod-cone dysfunction. Neither had retinoschisin (RS1) gene mutations. Biological mother and sister presented with retinal pigment epithelium (RPE) changes and abnormal cone-rod ERG responses. On further testing, next generation sequencing with array comparative genomic hybridisation showed a deletion in exon 4 of the CRX gene. Cystoid maculopathy in young male children can be difficult to distinguish from RS1-associated schisis. Phenotypic variants within a family must prompt a thorough retinal dystrophy evaluation even with electronegative ERG in the presenting child. This novel phenotype for CRX presents with optic nerve swelling and cystoid maculopathy in men, and RPE changes in women.

Pattern dystrophy-like changes and coquille d'oeuf atrophy in elderly patients affected by pseudoxanthoma elasticum

PURPOSE

To evaluate the retinal features of elderly patients affected by pseudoxanthoma elasticum (PXE).

MATERIALS AND METHODS

This is a retrospective case series of 62 eyes of 31 elderly PXE patients (age > 50 years). Clinical data, ultra-widefield fundus imaging (color, red-free (RF), infra-red imaging (IR), fundus autofluorescence (FAF)), and OCT examinations were collected. Diagnosis was confirmed by genetic testing or skin biopsy.

RESULTS

Thirty-one patients (10 males and 21 females (mean age 61.3 years, range 50-74 years)) were included in our study. Visual acuity ranged from 20/20 Snellen equivalent to 20/200. The mean follow-up was 66.4 ± 20.7 months (range 10-88). Pattern dystrophy-like changes (PD) (52 eyes of 26 patients, 83.8%) and atrophy resembling the "diffuse trickling" pattern described in geographic atrophy were present in the majority of patients. Twenty-three eyes of 12 patients (67.6%) had peripapillary atrophy, 9 eyes of 5 patients (26.4%) macular atrophy, 6 eyes of 3 patients (17.6%) displayed posterior pole atrophy and in 6 eyes of 3 patients (17.6%), atrophy could be detected beyond the vascular arcades (mid-peripheral atrophy). End-stage atrophy covered the entire area indicated as "coquille d'oeuf" (eggshell). Choroidal neovascularization occurred in 49 eyes of 26 patients (94.2%) with PD and in 6 eyes of 3 patients (60%) without PD. Genetic examinations were available for 29 patients (29/31, 93.5%).

CONCLUSIONS

The elderly PXE patients were characterized by pattern dystrophy-like changes with more or less extensive atrophy, progressive over time, which in some cases affected the whole area of the coquille d'oeuf during the course of the disease.

Reviewing the Role of Ultra-Widefield Imaging in Inherited Retinal Dystrophies

Inherited retinal dystrophies (IRD) are a heterogeneous group of rare chronic disorders caused by genetically determined degeneration of photoreceptors and retinal pigment epithelium cells. Ultra-widefield (UWF) imaging is a useful diagnostic tool for evaluating retinal integrity in IRD, including Stargardt disease, retinitis pigmentosa, cone dystrophies, and Best vitelliform dystrophy. Color or pseudocolor and fundus autofluorescence images obtained with UWF provide previously unavailable information on the retinal periphery, which correlates well with visual field measurement or electroretinogram. Despite unavoidable artifacts of the UWF device, the feasibility of investigations in infants and in patients with poor fixation makes UWF imaging a precious resource in the diagnostic armamentarium for IRD.

Ultra-widefield retinal imaging: an update on recent advances

The development of ultra-widefield retinal imaging has accelerated our understanding of common retinal diseases. As we continue to validate the diagnostic and prognostic significance of pathology in the retinal periphery, the ability to visualize and evaluate these features in an efficient and patient-friendly manner will become more important. Current interest in ultra-widefield imaging includes the development of potential biomarkers of disease progression and indicators of preclinical disease development. This article reviews the current ultra-widefield imaging systems and recent advances in their applications to clinical practice with a focus on diabetic retinopathy, retinal vein occlusion, uveitis, and pediatric retina.

Double hyperautofluorescent ring on fundus autofluorescence in ABCA4

We report an unusual phenotype in a child with a clinical diagnosis of recessive Stargardt disease (STGD1) and two pathogenic variants in the ABCA4 gene. Typically, the diagnosis of early-onset STGD1 is challenging because children may present with a variety of fundus changes and a variable rate of progression. At the time of his initial visit, the 6-year-old boy presented with 20/200 OD (right eye) and 20/150 OS (left eye), symmetrical mild foveal atrophy without flecks on fundus exam, and foveal hypoautofluorescence surrounded by a homogeneous hyperautofluorescent background on wide-field fundus autofluorescence. Over 4 years of follow-up, the retinal atrophy continued to progress, resulting in two well-defined and concentric hyperautofluorescent rings: one ring located at the posterior pole and the other located around the peripapillary region. Visual acuity also deteriorated to counting fingers at 4ft OD and 20/500 OS. To the best of our knowledge, this phenotype has not been previously described with the ABCA4 gene.