Pseudo-vitelliform macular detachment and cuticular drusen: exclusion of 6 candidate genes

Clinical Manifestations of Cuticular Drusen: Current Perspectives

Cuticular drusen are part of the spectrum of age-related macular degeneration (AMD) with particular clinical and multimodal imaging characteristics. This drusen subpopulation shares several high-risk single nucleotide polymorphisms with AMD. Despite this feature, they can manifest at a relatively young age, presenting with a female preponderance. Multimodal imaging is essential for characterizing such lesions, using a combination of color fundus photographs, optical coherence tomography (OCT), fluorescein angiography (FA), and fundus autofluorescence (FAF). The classic starry-sky pattern visible on FA and the typical central hypoautofluorescent lesion with hyperautofluorescent rim on FAF is considered the result of a central retinal pigment epithelium (RPE) erosion from these triangular elevations of the RPE-basal lamina. This finding may also be responsible for the typical choroidal hypertransmission appreciated through OCT. The clinical course of cuticular drusen may be relatively benign at early stages, with small drusen presenting at a young age. However, the presence of clinical phenotypes characterized by diffuse involvement and/or accompanying large drusen in patients older than 60 years may confer a significant risk for either macular neovascularization or geographic atrophy.

PRPH2 mutation update: In silico assessment of 245 reported and 7 novel variants in patients with retinal disease

Mutations in PRPH2, encoding peripherin-2, are associated with the development of a wide variety of inherited retinal diseases (IRDs). To determine the causality of the many PRPH2 variants that have been discovered over the last decades, we surveyed all published PRPH2 variants up to July 2020, describing 720 index patients that in total carried 245 unique variants. In addition, we identified seven novel PRPH2 variants in eight additional index patients. The pathogenicity of all variants was determined using the ACMG guidelines. With this, 107 variants were classified as pathogenic, 92 as likely pathogenic, one as benign, and two as likely benign. The remaining 50 variants were classified as variants of uncertain significance. Interestingly, of the total 252 PRPH2 variants, more than half (n = 137) were missense variants. All variants were uploaded into the Leiden Open source Variation and ClinVar databases. Our study underscores the need for experimental assays for variants of unknown significance to improve pathogenicity classification, which would allow us to better understand genotype-phenotype correlations, and in the long-term, hopefully also support the development of therapeutic strategies for patients with PRPH2-associated IRD.

Incidence and risk factors for macular atrophy in Acquired Vitelliform Lesions

PURPOSE

To study the time course to macular atrophy (MA) and associated risk factors in eyes with Acquired Vitelliform Lesions (AVL) as they vary between patients and between eyes of an individual.

DESIGN

Single centre, retrospective, observational cohort study.

SUBJECTS

Consecutive patients registered between Jan 2009 to Jan 2014 with first diagnosis of AVL confirmed by multimodal imaging were included. Eyes with baseline MA or choroidal neovascularization were excluded.

METHODS

Patient demographics were collected. Serial optical coherence tomography (OCT) scans and fundus autofluorescence (FAF) were graded and analysed. Turnbull's estimator was employed, and time censored at 5 years. Multivariable Weibull parametric proportional hazards models was used to assess association of risk factors with MA, following adjustment for age and gender. Hazard ratios are reported with 95% CI.

MAIN OUTCOME MEASURE

Time to the first OCT evidence of MA stratified by presenting visual acuity (VA) and AVL lesion subtypes. Secondary outcome included risk factors for incident MA.

RESULTS

A total of 237 eyes (132 patients) met the inclusion criteria. Incident MA was detected in 52/237 (21.9%) eyes by 5 years. Stratified by baseline VA, 40.3%eyes with VA≤ 70 letters developed atrophy within 5 years of first diagnosis in contrast to 10.3% eyes with VA>70 letters (p<0.001). Based on lesion type only 12.9% eyes with vitelliform lesion at baseline developed MA versus 39.8% and 44.2% eyes with pseudohypopyon or vitelliruptive lesion type respectively. In adjusted analysis, baseline factors associated with increased risk of MA included VA≤70 letters (HR 5.54; 95% CI 2.30-13.34), base width (HR 1.22; 95% CI 1.16-1.28), maximum height (HR 2.61; 95% CI 1.82-3.74), presence of SDD (HR 2.83; 95% CI 1.34 -5.96) and disrupted external limiting membrane (HR 2.81; 95% CI 1.34-5.86).

CONCLUSION

Baseline VA of 70 letters or less (Snellen ≤20/40) and pseudohypopyon or vitelliruptive lesion type attribute highest risk for MA. Other prognostic indicators for MA include baseline presence of SDD, disrupted ELM and larger lesion area.

Long-Range PCR-Based NGS Applications to Diagnose Mendelian Retinal Diseases

The purpose of this study was to develop a flexible, cost-efficient, next-generation sequencing (NGS) protocol for genetic testing. Long-range polymerase chain reaction (PCR) amplicons of up to 20 kb in size were designed to amplify entire genomic regions for a panel (n = 35) of inherited retinal disease (IRD)-associated loci. Amplicons were pooled and sequenced by NGS. The analysis was applied to 227 probands diagnosed with IRD: (A) 108 previously molecularly diagnosed, (B) 94 without previous genetic testing, and (C) 25 undiagnosed after whole-exome sequencing (WES). The method was validated with 100% sensitivity on cohort A. Long-range PCR-based sequencing revealed likely causative variant(s) in 51% and 24% of proband from cohorts B and C, respectively. Breakpoints of 3 copy number variants (CNVs) could be characterized. Long-range PCR libraries spike-in extended coverage of WES. Read phasing confirmed compound heterozygosity in 5 probands. The proposed sequencing protocol provided deep coverage of the entire gene, including intronic and promoter regions. Our method can be used (i) as a first-tier assay to reduce genetic testing costs, (ii) to elucidate missing heritability cases, (iii) to characterize breakpoints of CNVs at nucleotide resolution, (iv) to extend WES data to non-coding regions by spiking-in long-range PCR libraries, and (v) to help with phasing of candidate variants.

Differential diagnosis algorithms of сentral serous chorioretinopathy and adult-onset vitelliform dystrophies

Purpose.To optimize the differential diagnosis of chronic central serous chorioretinopathy (CSCR) and of adult-onset vitelliform dystrophies (VD). Research objectives. On the multimodal diagnosis basis, to investigate signs characteristic for VD and chronic CSCR using mathematic modeling, to elaborate algorithms of their differential diagnosis in settings of differently equipped clinics. Materials and methods.61 patient (90 eyes) with long-term neuroepithelial detachments (NEDs) were included in the study. In all patients, the disease history was collected, including the family history; all patients underwent a standard ophthalmologic examination: visual acuity testing including best corrected visual acuity (BCVA), biomicroophthalmoscopy, fundus photography, spectral domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCT-A), short-wavelength autofluorescence (SW-AF), fluorescein angiography (FA), indocyanine green angiography (ICGA). Patients were divided into two groups: with vitelliform dystrophies 30 patients (30 eyes), and with CSCR 31 patients (31 eyes). To estimate the probability of disease detection, binary logistic regression method was used. Results.Diagnostic predictors found in both groups were scrutinized; mathematical models for estimating the probability of disease detection were obtained. Differential diagnostics algorithms have been developed taking into account the resulting formulas for calculating the probability of disease detection, including criteria of different examination combinations: SD-OCT (area under ROC curve 0.946); BAF (area under ROC curve 0.955), SD-OCT and SW-AF (area under ROC curve 0.980); SW-AF, FA and ICGA (area under ROC curve 0.989). Conclusion.The obtained models make it possible to carry out differential diagnosis of vitelliform dystrophies and chronic CSCR in settings of differently equipped clinics.

Clinical manifestations of cuticular drusen in Korean patients

Cuticular drusen show some similarities to and differences from soft drusen in age-related macular degeneration (AMD) and might thus be a unique AMD subtype. Previous studies on cuticular drusen were performed mainly in white ethnic groups, but AMD shows ethnic differences. We investigated clinical manifestations of cuticular drusen in Korean patients to evaluate possible ethnic differences. Clinical records of Korean patients with cuticular drusen were retrospectively reviewed. Fundus distribution pattern, imaging features, and presence of large drusen, drusenoid pigment epithelial detachment (PED), and macular complications, including geographic atrophy (GA), choroidal neovascularization (CNV), and acquired vitelliform lesion (AVL), were assessed via multimodal imaging in 162 eyes with cuticular drusen (n = 81 patients; 67 females; mean age: 66.6 ± 9.1 years). Diffuse distribution was found in 61.7% and peripapillary involvement in 75.3% of eyes. Large drusen, drusenoid PED, GA, CNV, and AVL were observed in 59.3%, 26.5%, 18.5%, 3.7%, and 1.2% of eyes, respectively. The macular complication prevalence was similar between patients ≤ 60 and those > 60 years old. In Korean patients, cuticular drusen were less frequently associated with macular complications than in white patients, and the proportion of macular complications differed significantly, with AVL representing an uncommon complication.

PRPH2 mutation as the cause of various clinical manifestations in a family affected with inherited retinal dystrophy

Background/Objectives: To reveal the underlying genetic defect in a complex family affected with different clinical features of inherited retinal dystrophy, we carried out whole exome sequencing followed by confirmatory molecular tests.Materials and Methods: Complete ophthalmic examinations were performed for available affected family members. Whole exome sequencing, bioinformatics analysis, Sanger sequencing confirmation, and segregation analysis were done to identify the causative mutation.Results: Clinical findings suggested fundus flavimaculatus as an early clinical feature progressing to an extensive chorioretinal atrophy involving the macula and mid-periphery of the fundus in one parent and central areolar chorioretinal dystrophy (CACD) as the most probable clinical diagnosis in another parent. Macular pattern dystrophy for one of their daughters and a Leber congenital amaurosis (LCA) like phenotype for the daughter with an early onset retinal dystrophy (EORD) phenotype was suggested. We found a known pathogenic nonsense variation in the PRPH2 gene (NM_000322: p.Gln239Ter). The parents with end stage fundus flavimaculatus and CACD diagnosis and their daughter with macular pattern dystrophy were heterozygous for the identified variant. The daughter affected with EORD/LCA like retinal dystrophy was homozygous for the same variation.Conclusions: In this family, the same pathogenic variant in PRPH2 gene showed a wide range of clinical features of extensive chorioretinal macular atrophy with flecks as fundus falvimaculatus to CACD and macular pattern dystrophy in the heterozygous inheritance pattern and early onset/LCA like retinal dystrophy in the patient who was homozygous for the causative variant.

Adult-Onset Vitelliform Macular Dystrophy caused by BEST1 p.Ile38Ser Mutation is a Mild Form of Best Vitelliform Macular Dystrophy

Adult-onset vitelliform macular dystrophy (AVMD) is a common and benign macular degeneration which can be caused by BEST1 mutation. Here, we investigated the clinical characteristics associated with a newly identified BEST1 mutation, p.Ile38Ser and confirmed the associated physiological functional defects. The 51-year-old patient presented bilateral small subretinal yellow deposits. Consistent with AVMD, the corresponding lesions showed hyperautofluorescence, late staining in fluorescein angiography, and subretinal hyper-reflective materials in spectral-domain optical coherence tomography. Genetic analysis demonstrated that the patient presented with a heterozygous p.Ile38Ser BEST1 mutation. Surface biotinylation and patch clamp experiments were performed in transfected HEK293T cells. Although, the identified BEST1 mutant maintains normal membrane expression, p.Ile38Ser mutant showed significantly smaller currents than wild type (WT). However, it showed larger currents than other BEST1 mutants, p.Trp93Cys, causing autosomal dominant best vitelliform macular dystrophy (BVMD), and p.Ala195Val, causing autosomal recessive bestrophinopathy (ARB). The cells expressing both WT and each BEST1 mutant showed that the functional defect of p.Ile38ser was milder than that of p.Trp93Cys, whereas combination of p.Ala195Val with WT showed good current. We identified and described the phenotype and in vitro functions of a novel BEST1 mutation causing AVMD. AVMD induced by p.Ile38Ser BEST1 mutation is a mild form of BVMD.

CHOROIDAL THICKENING IN PATIENTS WITH CUTICULAR DRUSEN COMBINED WITH VITELLIFORM MACULAR DETACHMENT

PURPOSE

To analyze the subfoveal choroidal thickness (SFCT) in patients with cuticular drusen.

METHODS

Retrospective, monocentric, study of consecutive patients examined with enhanced depth imaging spectral domain optical coherence tomography (EDI SD-OCT, Cirrus, Zeiss) between 2009 and 2014 in a tertiary care center. Measurements of the height of the subfoveal vitelliform detachment and SFCT were manually performed.

RESULTS

Thirteen patients, 3 men and 10 women, aged from 35 to 73 (mean: 53.6 years) were selected. For the 24 eyes without macular atrophy at first visit, SFCT ranged from 195 to 559 µm (mean ± SD = 317.5 ± 93). The SFCT was significantly thicker in 12 eyes with vitelliform macular detachment at presentation (369 ± 96, median = 368.5) than in 12 eyes without (266 ± 58, median = 257.5) (P = 0.007), whereas the 2 groups did not differ in age (P = 0.35) or refractive error (P = 0.56). No correlation was observed between SFCT and the height of the foveal detachment. For 10 eyes followed up longer than 24 months (mean: 38.9 months), the SFCT significantly decreased over time, from 375 ± 96 (median = 368.5) to 303 ± 138 (median = 319) µm (P = 0.022).

CONCLUSION

Eyes with cuticular drusen combined with vitelliform macular detachment present with choroidal thickening, suggesting that the choroidal vasculature may play a role in the occurrence of macular detachments in patients with cuticular drusen. The life cycle of these vitelliform lesions evolves from translucent subretinal fluid to the accumulation of yellowish material eventually resolving and leading to atrophy with marked and rapid thinning of the choroid.