Clinical Features of a Retinopathy Associated With a Dominant Allele of the RGR Gene

Purpose

We describe the clinical features in two pedigrees with dominantly inherited retinopathy segregating the previously reported frameshifting mutation, c.836dupG (p.Ile280Asn*78) in the terminal exon of the RGR gene, and compare their haplotypes to that of the previously reported pedigree.

Methods

The probands were ascertained at West Virginia University Eye Institute (WVU) and Moorfields Eye Hospital (MEH) through next generation sequencing (NGS) and whole genome sequencing (WGS) respectively. Clinical data included visual acuity (VA), visual fields, fundus autofluorescence (FAF), optical coherence tomography (OCT), and electroretinography (ERG). Haplotype analysis was performed using Sanger sequencing of the DNA from the molecularly ascertained individuals from the three pedigrees.

Results

Nine heterozygous mutation carriers were identified in two families. Four carriers were asymptomatic; five carriers had variable VA reduction, visual field constriction, and experienced difficulty under dim illumination. Fundus examination of the asymptomatic carriers showed diffuse or reticular pigmentation of the retina; the symptomatic carriers had chorioretinal atrophy. FAF imaging showed widespread signal loss in advanced retinopathy, and reticular hyperautofluorescence in mild cases. OCT showed loss of outer retinal lamina in advanced disease. ERG showed moderate-to-severe rod–cone dysfunction in two symptomatic carriers; and was normal in three asymptomatic carriers. A shared haplotype flanking the mutation of up to 6.67 Mb was identified in both families. Within this region, 1.27 Mb were shared with the first family reported with this retinopathy.

Conclusions

The clinical data suggest a variable and slow degeneration of the RPE. A shared chromosomal segment surrounding the RGR gene suggests a single ancestral mutational event underlying all three families.

Detailed clinical characterisation, unique features and natural history of autosomal recessive RDH12-associated retinal degeneration

BACKGROUND

Defects in retinol dehydrogenase 12 (RDH12) account for 3.4%-10.5 % of Leber congenital amaurosis and early-onset severe retinal dystrophy (EOSRD) and are a potential target for gene therapy. Clinical trials in inherited retinal diseases have unique challenges, and natural history studies are critical to successful trial design. The purpose of this study was to characterise the natural history of RDH12-associated retinal degeneration.

METHODS

A retrospective chart review was performed in individuals with retinal degeneration and two likely disease-causing variants in RDH12.

RESULTS

57 subjects were enrolled from nine countries. 33 subjects had clinical records available from childhood. The data revealed an EOSRD, with average age of onset of 4.1 years. Macular atrophy was a universal clinical finding in all subjects, as young as 2 years of age. Scotopic and photopic electroretinography (ERG) responses were markedly reduced in all subjects, and a non-recordable ERG was documented as young as 1 year of age. Assessment of visual acuity, visual field and optical coherence tomography revealed severe loss of function and structure in the majority of subjects after the age of 10 years. Widefield imaging in 23 subjects revealed a unique, variegated watercolour-like pattern of atrophy in 13 subjects and sparing of the peripapillary area in 18 subjects.

CONCLUSIONS

This study includes the largest collection of phenotypic data from children with RDH12-associated EOSRD and provides a comprehensive description of the timeline of vision loss in this severe, early-onset condition. These findings will help identify patients with RDH12-associated retinal degeneration and will inform future design of therapeutic trials.

Identification and characterization of the VAX2 p.Leu139Arg variant: possible involvement of VAX2 in cone dystrophy

OBJECTIVE

This study was undertaken with the objective to investigate the potential involvement of VAX2 in retinal degeneration.

METHODS

A cohort of macular and cone dystrophy patients (n = 70) was screened for variant identification. Polymerase chain reaction (PCR) products were purified using ExoSAP-IT. Direct sequencing of PCR products was performed using BigDye 3.1 on the ABI 3730 DNA Analyzer and analyzed using DNASTAR software tool. Search for known variant was performed using the following platforms: 1000 Genomes Project, Ensembl, UCSC, ExAc, and dbSNP. The VAX2 mutants were generated using the GeneArt® Site-Directed Mutagenesis kit. In vitro analysis was performed in hTERTRPE-1 (RPE-1) cell line. Cells were photographed using a Zeiss AXIOVERT S100 microscope. Images were analyzed using Photoshop CS4 software.

RESULTS

Here, we report the identification of a heterozygous non-synonymous variant (c.416T>G; p.Leu139Arg) in one cone dystrophy proband. Functional characterization of this variant in vitro revealed an aberrant phenotype seen as protein mislocalization to cytoplasm/nucleus and aggregates undergoing degradation or forming aggresomes. The cellular phenotype suggests protein loss-of-function. Analysis of the VAX2 p.Leu139Met, a variant present in the normal population, showed a phenotype similar to the wild-type, further supporting the hypothesis for the Leucine 139 to Arginine change to be damaging.

CONCLUSIONS

This study raises the interesting possibility for evaluating VAX2 as a candidate gene for cone dystrophy.

Loss-of-Function Mutations in the CFH Gene Affecting Alternatively Encoded Factor H-like 1 Protein Cause Dominant Early-Onset Macular Drusen

Purpose

To characterize the molecular mechanism underpinning early-onset macular drusen (EOMD), a phenotypically severe subtype of age-related macular degeneration (AMD), in a subgroup of patients.

Design

Multicenter case series, in vitro experimentation, and retrospective analysis of previously reported variants.

Participants

Seven families with apparently autosomal dominant EOMD.

Methods

Patients underwent a comprehensive ophthalmic assessment. Affected individuals from families A, B, and E underwent whole exome sequencing. The probands from families C, D, F, and G underwent Sanger sequencing analysis of the complement factor H (CFH) gene. Mutant recombinant factor H like-1 (FHL-1) proteins were expressed in HEK293 cells to assess the impact on FHL-1 expression and function. Previously reported EOMD-causing variants in CFH were reviewed.

Main Outcome Measures

Detailed clinical phenotypes, genomic findings, in vitro characterization of mutation effect on protein function, and postulation of the pathomechanism underpinning EOMD.

Results

All affected participants demonstrated bilateral drusen. The earliest reported age of onset was 16 years (median, 46 years). Ultra-rare (minor allele frequency [MAF], ≤0.0001) CFH variants were identified as the cause of disease in each family: CFH c.1243del, p.(Ala415ProfsTer39) het; c.350+1G→T het; c.619+1G→A het, c.380G→A, p.(Arg127His) het; c.694C→T p.(Arg232Ter) het (identified in 2 unrelated families in this cohort); and c.1291T→A, p.(Cys431Ser). All mutations affect complement control protein domains 2 through 7, and thus are predicted to impact both FHL-1, the predominant isoform in Bruch’s membrane (BrM) of the macula, and factor H (FH). In vitro analysis of recombinant proteins FHL-1_R127H, FHL-1_A415f/s, and FHL-1_C431S demonstrated that they are not secreted, and thus are loss-of-function proteins. Review of 29 previously reported EOMD-causing mutations found that 75.8% (22/29) impact FHL-1 and FH. In total, 86.2% (25/29) of EOMD-associated variants cause haploinsufficiency of FH or FHL-1.

Conclusions

Early-onset macular drusen is an underrecognized, phenotypically severe subtype of AMD. We propose that haploinsufficiency of FHL-1, the main regulator of the complement pathway in BrM, where drusen develop, is an important mechanism underpinning the development of EOMD in a number of cases. Understanding the molecular basis of EOMD will shed light on AMD pathogenesis given their pathologic similarities.

Isolated rod dysfunction associated with a novel genotype of CNGB1

Purpose

To describe the clinical and electrophysiological features of an unusual retinopathy in a patient with a novel genotype of CNGB1, mutations in which are implicated in autosomal recessive retinitis pigmentosa (rod-cone dystrophy).

Observations

A 61-year old asymptomatic woman was referred to the inherited retinal disorders clinic because of peripheral retinal pigmentary changes. She had normal visual acuity and color vision. Clinical examination and detailed imaging of the macula were normal, but there was atrophy of the outer retina in the periphery with sparse intra-retinal pigmentation. Electroretinography (ERG) revealed undetectable rod responses, with normal cone-mediated responses. The pattern ERG was normal. Genetic analysis identified two previously unreported variants in CNGB1: (c.2258T > A, p.[Leu753*] and c.807G > C, p.[Gln269His]), shown to be in trans.

Conclusions and importance

This report describes a functionally cone-isolated retina in an adult, apparently hemizygous for a novel missense mutation in CNGB1, a novel phenotype for this gene. The p.[Gln269His] allele is the first missense change, within the glutamic acid-rich protein (GARP) domain of CNGB1, to be associated with retinal disease in humans.

Phagosomal and mitochondrial alterations in RPE may contribute to KCNJ13 retinopathy

Mutations in KCNJ13 are associated with two retinal disorders; Leber congenital amaurosis (LCA) and snowflake vitreoretinal degeneration (SVD). We examined the retina of kcnj13 mutant zebrafish (obelix^td15, c.502T > C p.[Phe168Leu]) to provide new insights into the pathophysiology underlying these conditions. Detailed phenotyping of obelix^td15 fish revealed a late onset retinal degeneration at 12 months. Electron microscopy of the obelix^td15 retinal pigment epithelium (RPE) uncovered reduced phagosome clearance and increased mitochondrial number and size prior any signs of retinal degeneration. Melanosome distribution was also affected in dark-adapted 12-month obelix^td15 fish. At 6 and 12 months, ATP levels were found to be reduced along with increased expression of glial fibrillary acidic protein and heat shock protein 60. Quantitative RT-PCR of polg2, fis1, opa1, sod1/2 and bcl2a from isolated retina showed expression changes consistent with altered mitochondrial activity and retinal stress. We propose that the retinal disease in this model is primarily a failure of phagosome physiology with a secondary mitochondrial dysfunction. Our findings suggest that alterations in the RPE and photoreceptor cellular organelles may contribute to KCNJ13-related retinal degeneration and provide a therapeutic target.

Unique noncoding variants upstream of PRDM13 are associated with a spectrum of developmental retinal dystrophies including progressive bifocal chorioretinal atrophy

The autosomal dominant progressive bifocal chorioretinal atrophy (PBCRA) disease locus has been mapped to chromosome 6q14-16.2 that overlaps the North Carolina macular dystrophy (NCMD) locus MCDR1. NCMD is a nonprogressive developmental macular dystrophy, in which variants upstream of PRDM13 have been implicated. Whole genome sequencing was performed to interrogate structural variants (SVs) and single nucleotide variants (SNVs) in eight individuals, six affected individuals from two families with PBCRA, and two individuals from an additional family with a related developmental macular dystrophy. A SNV (chr6:100,046,804T>C), located 7.8 kb upstream of the PRDM13 gene, was shared by all PBCRA-affected individuals in the disease locus. Haplotype analysis suggested that the variant arose independently in the two families. The two affected individuals from Family 3 were screened for rare variants in the PBCRA and NCMD loci. This revealed a de novo variant in the proband, 21 bp from the first SNV (chr6:100,046,783A>C). This study expands the noncoding variant spectrum upstream of PRDM13 and suggests altered spatio-temporal expression of PRDM13 as a candidate disease mechanism in the phenotypically distinct but related conditions, NCMD and PBCRA.

ABCA4-associated disease as a model for missing heritability in autosomal recessive disorders: novel noncoding splice, cis-regulatory, structural, and recurrent hypomorphic variants

Purpose

ABCA4-associated disease, a recessive retinal dystrophy, is hallmarked by a large proportion of patients with only one pathogenic ABCA4 variant, suggestive for missing heritability.

Methods

By locus-specific analysis of ABCA4, combined with extensive functional studies, we aimed to unravel the missing alleles in a cohort of 67 patients (p), with one (p = 64) or no (p = 3) identified coding pathogenic variants of ABCA4.

Results

We identified eight pathogenic (deep-)intronic ABCA4 splice variants, of which five are novel and six structural variants, four of which are novel, including two duplications. Together, these variants account for the missing alleles in 40.3% of patients. Furthermore, two novel variants with a putative cis-regulatory effect were identified. The common hypomorphic variant c.5603A>T p.(Asn1868Ile) was found as a candidate second allele in 43.3% of patients. Overall, we have elucidated the missing heritability in 83.6% of our cohort. In addition, we successfully rescued three deep-intronic variants using antisense oligonucleotide (AON)-mediated treatment in HEK 293-T cells and in patient-derived fibroblast cells.

Conclusion

Noncoding pathogenic variants, novel structural variants, and a common hypomorphic allele of the ABCA4 gene explain the majority of unsolved cases with ABCA4-associated disease, rendering this retinopathy a model for missing heritability in autosomal recessive disorders.

Whole genome sequencing reveals novel mutations causing autosomal dominant inherited macular degeneration

BACKGROUND

Age-related macular degeneration (AMD) is a common sight threatening condition. However, there are a number of monogenic macular dystrophies that are clinically similar to AMD, which can potentially provide pathogenetic insights.

METHODS

Three siblings from a non-consanguineous Greek-Cypriot family reported central visual disturbance and nyctalopia. The patients had full ophthalmic examinations and color fundus photography, spectral-domain ocular coherence tomography and scanning laser ophthalmoscopy. Targeted polymerase chain reaction (PCR) was performed as a first step to attempt to identify suspected mutations in C1QTNF5 and TIMP3 followed by whole genome sequencing.

RESULTS

The three patients were noted to have symptoms of nyctalopia, early paracentral visual field loss and, in older patients, central vision loss. Imaging identified pseudodrusen, retinal atrophy and RPE-Bruch's membrane separation. Whole genome sequencing of the proband revealed two novel heterozygous variants in C1QTNF5, c.556C>T, and c.569C>G. The mutation segregated with disease in this family, occurred in cis, and resulted in missense amino acid changes P186S and S190W in C1QTNF5. In silico modeling of the variants revealed that the S190W mutations was likely to have the greatest pathologic effect and that the combination of the mutations was likely to have an additive effect.

CONCLUSIONS

The novel mutations in C1QTNF5 identified here expand the genotypic spectrum of mutations causing late-onset retinal dystrophy.

Macular spatial distribution of preserved autofluorescence in patients with choroideremia

BACKGROUND/AIMS

To better understand the pattern of degeneration progression in cases with choroideremia.

METHODS

A cohort of genotypically confirmed choroideremia cases who underwent optical coherence tomography (OCT) and fundus autofluorescence (FAF) imaging was studied. Using HEYEX review software, the foveal centre was marked on FAF images under guidance of corresponding OCT images, followed by application of an ETDRS grid. The boundaries of preserved autofluorescence (AF) were manually segmented in each individual ETDRS subfield. The regional distribution of preserved AF was assessed by comparing its area among the various subfields.

RESULTS

A total of 168 eyes from 84 choroideremia cases were enrolled. There was a statistically significant difference in the amount of preserved AF area between inner subfields as determined by one-way analysis of variance (F (3,668)=9.997, p<0.001) and also between outer subfields (F (3,668)=8.348, p<0.001). A Tukey posthoc test revealed that the preserved AF area in the nasal subfields in both the inner and outer subfields was significantly smaller compared with analogue subfields.

CONCLUSION

The asymmetric spatial distribution of preserved AF in choroideremia (corresponding to the stellate shaped nature of these regions) suggests that the progression of degeneration has directional preference.

Prevalence of cystoid macular oedema, epiretinal membrane and cataract in retinitis pigmentosa

Background/Aims

To report the prevalence of treatable complications (cystoid macular oedema, CME; epiretinal membrane, ERM and cataract) in patients with retinitis pigmentosa (RP).

Methods

Consecutive patients with RP attending a tertiary eye clinic in 2012. Spectral domain-optical coherence tomography was used to determine presence of CME and ERM. Clinic records were reviewed to identify cataract and pseudophakia. Multivariable analyses adjusted for age, gender and other confounders.

Results

Data are presented for 338 eyes from 169 patients. CME was present in 58.6% of patients and 50.9% of eyes and was bilateral in 73.7%. ERM, cataract and pseudophakia were present in 22.8%, 23.4% and 11.2% eyes, respectively. In multivariable analyses, CME was associated with younger age (OR 0.81, 95% CI 0.67 to 0.98) but not with gender. Patients with ERM and cataract/pseudophakia were less likely to also have CME (OR 0.19, 95% CI 0.09 to 0.40 and OR 0.37, 95% CI 0.16 to 0.84, respectively). CME was most prevalent in patients with autosomal-dominant inheritance (71.4%), followed by autosomal recessive/sporadic inheritance (58.9%) and least likely in persons with X linked inheritance (12.5%, p<0.001).

Conclusions

The prevalence of treatable RP complications is high and suggests it may be clinically beneficial to screen patients with RP to identify those who may benefit from current or future interventions.

Beneficial effects on vision in patients undergoing retinal gene therapy for choroideremia

Retinal gene therapy is increasingly recognized as a novel molecular intervention that has huge potential in treating common causes of blindness, the majority of which have a genetic aetiology1-5. Choroideremia is a chronic X-linked retinal degeneration that was first described in 18726. It leads to progressive blindness due to deficiency of Rab-escort protein 1 (REP1). We designed an adeno-associated viral vector to express REP1 and assessed it in a gene therapy clinical trial by subretinal injection in 14 patients with choroideremia. The primary endpoint was vision change in treated eyes 2 years after surgery compared to unoperated fellow eyes. Despite complications in two patients, visual acuity improved in the 14 treated eyes over controls (median 4.5 letter gain, versus 1.5 letter loss, P = 0.04), with 6 treated eyes gaining more than one line of vision (>5 letters). The results suggest that retinal gene therapy can sustain and improve visual acuity in a cohort of predominantly late-stage choroideremia patients in whom rapid visual acuity loss would ordinarily be predicted.

Novel homozygous splicing mutations in ARL2BP cause autosomal recessive retinitis pigmentosa

Purpose

Mutations in ARL2BP, encoding ADP-ribosylation factor-like 2 binding protein, have recently been implicated as a cause of autosomal recessive retinitis pigmentosa (arRP), with three homozygous variants identified to date. In this study, we performed next-generation sequencing to reveal additional arRP cases associated with ARL2BP variants.

Methods

Whole-genome sequencing (WGS) or whole-exome sequencing (WES) was performed in 1,051 unrelated individuals recruited for the UK Inherited Retinal Disease Consortium and NIHR-BioResource Rare Diseases research studies. Sanger sequencing was used to validate the next-generation sequencing data, and reverse transcriptase (RT)-PCR analysis was performed on RNA extracted from blood from affected individuals to test for altered splicing of ARL2BP. Detailed phenotyping was performed, including clinical evaluation, electroretinography, fundus photography, fundus autofluorescence imaging, and spectral-domain optical coherence tomography.

Results

Homozygous variants in ARL2BP (NM_012106.3) were identified in two unrelated individuals with RP. The variants, c.207+1G>A and c.390+5G>A, at conserved splice donor sites for intron 3 and intron 5, respectively, were predicted to alter the pre-mRNA splicing of ARL2BP. RT-PCR spanning the affected introns revealed that both variants caused abnormal splicing of ARL2BP in samples from affected individuals.

Conclusions

This study identified two homozygous variants in ARL2BP as a rare cause of arRP. Further studies are required to define the underlying disease mechanism causing retinal degeneration as a result of mutations in ARL2BP and any phenotype-genotype correlation associated with residual levels of the wild-type transcript.

The treatment of refractory angle-closure glaucoma in a patient with X-linked juvenile retinoschisis

X-Linked Retinoschisis (XLRS) is a common genetically determined form of macular degeneration affecting young males. XLRS is due to mutations in the RS1 gene located on chromosome Xp22 which codes for retinoschisin and is estimated to affect between 1:5000 to 1:20000 individuals worldwide. We report a case of refractory angle-closure glaucoma in a thirty-nine-year-old Caucasian man with atypical XLRS. The patient presented with a two-day history of left eye pain, acutely reduced vision and a nine-month history of hemicranial pain. Examination identified left intraocular pressure (IOP) of 52mmHg. Gonioscopy confirmed complete angle closure. Following failure of medical management and persistently raised left IOP (43-46mmHg), the patient underwent left phacoemulsification and intraocular lens insertion without complication. After surgery, his IOP reduced to 10-14mmHg on all follow up examinations without the need for glaucoma drops. His iridocorneal angle remained open and vision improved to 20/100. Our case demonstrates the additional role of lens surgery in the treatment of secondary angle-closure glaucoma in the presence of an inherited retinal dystrophy. All patients with inherited retinopathy presenting with a headache or eye pain should undergo gonioscopic examination to exclude angle-closure glaucoma.

Phenopolis: an open platform for harmonization and analysis of genetic and phenotypic data

Summary

Phenopolis is an open-source web server providing an intuitive interface to genetic and phenotypic databases. It integrates analysis tools such as variant filtering and gene prioritization based on phenotype. The Phenopolis platform will accelerate clinical diagnosis, gene discovery and encourage wider adoption of the Human Phenotype Ontology in the study of rare genetic diseases.

Availability and Implementation

A demo of the website is available at https://phenopolis.github.io . If you wish to install a local copy, source code and installation instruction are available at https://github.com/phenopolis . The software is implemented using Python, MongoDB, HTML/Javascript and various bash shell scripts.

Contact

n.pontikos@ucl.ac.uk.

Supplementary information

Supplementary data are available at Bioinformatics online.

A clinical and molecular characterisation of CRB1-associated maculopathy

To date, over 150 disease-associated variants in CRB1 have been described, resulting in a range of retinal disease phenotypes including Leber congenital amaurosis and retinitis pigmentosa. Despite this, no genotype–phenotype correlations are currently recognised. We performed a retrospective review of electronic patient records to identify patients with macular dystrophy due to bi-allelic variants in CRB1. In total, seven unrelated individuals were identified. The median age at presentation was 21 years, with a median acuity of 0.55 decimalised Snellen units (IQR = 0.43). The follow-up period ranged from 0 to 19 years (median = 2.0 years), with a median final decimalised Snellen acuity of 0.65 (IQR = 0.70). Fundoscopy revealed only a subtly altered foveal reflex, which evolved into a bull’s-eye pattern of outer retinal atrophy. Optical coherence tomography identified structural changes—intraretinal cysts in the early stages of disease, and later outer retinal atrophy. Genetic testing revealed that one rare allele (c.498_506del, p.(Ile167_Gly169del)) was present in all patients, with one patient being homozygous for the variant and six being heterozygous. In trans with this, one variant recurred twice (p.(Cys896Ter)), while the four remaining alleles were each observed once (p.(Pro1381Thr), p.(Ser478ProfsTer24), p.(Cys195Phe) and p.(Arg764Cys)). These findings show that the rare CRB1 variant, c.498_506del, is strongly associated with localised retinal dysfunction. The clinical findings are much milder than those observed with bi-allelic, loss-of-function variants in CRB1, suggesting this in-frame deletion acts as a hypomorphic allele. This is the most prevalent disease-causing CRB1 variant identified in the non-Asian population to date.

Missense variants in the X-linked gene PRPS1 cause retinal degeneration in females

Retinal dystrophies are a heterogeneous group of disorders of visual function leading to partial or complete blindness. We report the genetic basis of an unusual retinal dystrophy in five families with affected females and no affected males. Heterozygous missense variants were identified in the X-linked phosphoribosyl pyrophosphate synthetase 1 (PRPS1) gene: c.47C > T, p.(Ser16Phe); c.586C > T, p.(Arg196Trp); c.641G > C, p.(Arg214Pro); and c.640C > T, p.(Arg214Trp). Missense variants in PRPS1 are usually associated with disease in male patients, including Arts syndrome, Charcot-Marie-Tooth, and nonsyndromic sensorineural deafness. In our study families, affected females manifested a retinal dystrophy with interocular asymmetry. Three unrelated females from these families had hearing loss leading to a diagnosis of Usher syndrome. Other neurological manifestations were also observed in three individuals. Our data highlight the unexpected X-linked inheritance of retinal degeneration in females caused by variants in PRPS1 and suggest that tissue-specific skewed X-inactivation or variable levels of pyrophosphate synthetase-1 deficiency are the underlying mechanism(s). We speculate that the absence of affected males in the study families suggests that some variants may be male embryonic lethal when inherited in the hemizygous state. The unbiased nature of next-generation sequencing enables all possible modes of inheritance to be considered for association of gene variants with novel phenotypic presentation.

Transcorneal electrical stimulation for the treatment of retinitis pigmentosa: results from the TESOLAUK trial

Objective

To explore the impact of weekly transcorneal electrical stimulation (TES) over a 6-month period as a treatment for retinitis pigmentosa (RP).

Methods and analysis

A prospective open-label observational trial was carried out assessing weekly TES in participants with RP for a period of 6 months followed by observation for a further 6 months. Clinical examination and investigations were carried out at 3 monthly intervals for a total of 12 months. The primary outcome measure explored safety through a descriptive analysis of adverse effects with secondary outcome measures evaluating structural and functional efficacy.

Results

Seven male and seven female participants with RP aged 18–80 years were recruited. TES was well tolerated with no serious adverse events reported. Two participants reported transient foreign body sensation and one participant had discomfort underneath the skin electrode. Following 6 months of TES, best-corrected visual acuity increased by 1.1±1.4 letters in the control arm and 0.93±1.4 letters in the treated arm. Central microperimetry threshold sensitivity rose by 0.02±0.5 decibels (dB) and 0.37±0.4 dB and Goldmann visual field volume by 0.16±0.09 steradians (sr) vs 0.22±0.12 sr for the control and treated eye, respectively. There was no statistical significance seen between eyes following the treatment or observation period.

Conclusion

This small open-label clinical trial showed that TES was safe and well tolerated in patients with RP. Visual function measurements at 6 months demonstrated no significant difference between the control and treated eyes. The results justify a larger clinical trial over a longer period of time in order to identify any treatment effect.

Quantitative and Qualitative Features of Spectral-Domain Optical Coherence Tomography Provide Prognostic Indicators for Visual Acuity in Patients With Choroideremia

BACKGROUND AND OBJECTIVE

To identify qualitative and quantitative features of spectral-domain optical coherence tomography (SD-OCT) as prognostic indicators of visual acuity (VA) loss in patients with choroideremia (CHM).

PATIENTS AND METHODS

Retrospective study of 57 male patients with CHM. Central foveal thickness (CFT), subfoveal choroidal thickness (SCT), fundus autofluorescence area, and evidence of outer retinal and choroidal degeneration were analyzed by SD-OCT.

RESULTS

Best-corrected VA logMAR at baseline was associated with CFT at baseline (r = -0.47; P < .01), CFT at most recent follow-up (r = -0.27; P < .01), and SCT at baseline (r = -0.31; P < .01). Ellipsoid zone (EZ) rupture was associated with a higher CFT loss (r = 0.33; P < .01) and macular cystic spaces (MCS) with a reduction in VA over time (hazard risk = 0.48; P = .05).

CONCLUSION

Reduced CFT at baseline, EZ rupture, and MCS are poor prognostic indicators for VA outcome. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:711-716.].

Factors associated with visual acuity in patients with cystoid macular oedema and Retinitis Pigmentosa

PURPOSE

Retinitis pigmentosa is the most common inherited retinal dystrophy. The factors associated with visual acuity in patients with other retinal diseases are well known, but are poorly understood in patients with retinitis pigmentosa. This knowledge is useful for prognosis and to support secondary endpoints in clinical trials.

METHODS

We conducted a cross-sectional study of consecutive patients recruited from the inherited retinal disease service from January 2012 to December 2012. Central macular thickness (CMT) was measured using spectral domain optical coherence tomography.

RESULTS

Data were available for 81 patients and 162 eyes. After multivariable analyses, older age, earlier age of onset of symptoms, and thicker CMT were associated with lower visual acuity. Gender and inheritance pattern were not associated with visual acuity. Each decade older age, younger age of onset, and thicker CMT was associated with 0.12, 0.10, and 0.11 worse logarithm of the minimal angle of resolution units of visual acuity, respectively (p < 0.05 for all).

CONCLUSIONS

Age, age of onset, and CMT are associated with visual acuity and important factors to measure in studies of retinitis pigmentosa.

Assessment of the incorporation of CNV surveillance into gene panel next-generation sequencing testing for inherited retinal diseases

BACKGROUND

Diagnostic use of gene panel next-generation sequencing (NGS) techniques is commonplace for individuals with inherited retinal dystrophies (IRDs), a highly genetically heterogeneous group of disorders. However, these techniques have often failed to capture the complete spectrum of genomic variation causing IRD, including CNVs. This study assessed the applicability of introducing CNV surveillance into first-tier diagnostic gene panel NGS services for IRD.

METHODS

Three read-depth algorithms were applied to gene panel NGS data sets for 550 referred individuals, and informatics strategies used for quality assurance and CNV filtering. CNV events were confirmed and reported to referring clinicians through an accredited diagnostic laboratory.

RESULTS

We confirmed the presence of 33 deletions and 11 duplications, determining these findings to contribute to the confirmed or provisional molecular diagnosis of IRD for 25 individuals. We show that at least 7% of individuals referred for diagnostic testing for IRD have a CNV within genes relevant to their clinical diagnosis, and determined a positive predictive value of 79% for the employed CNV filtering techniques.

CONCLUSION

Incorporation of CNV analysis increases diagnostic yield of gene panel NGS diagnostic tests for IRD, increases clarity in diagnostic reporting and expands the spectrum of known disease-causing mutations.

Association of C-Reactive Protein Genetic Polymorphisms With Late Age-Related Macular Degeneration

Importance

C-reactive protein (CRP) is a circulating inflammatory marker associated with late age-related macular degeneration (AMD). It remains uncertain whether the association between CRP concentrations and AMD is causal.

Objective

To assess whether CRP (OMIM 123260) single-nucleotide polymorphisms that influence circulating CRP concentrations are associated with late AMD.

Design, Setting, and Participants

Participants in 2 UK, hospital-based, case-control studies (Cambridge AMD study and Moorfields Eye Hospital AMD study) and 1 pan-European, cross-sectional, population-based study (the European Eye [EUREYE] Study) were recruited between November 6, 2000, and April 30, 2007. Participants underwent dilated stereo-digital fundus photography graded according to the International Classification of Age-related Maculopathy and Macular Degeneration. There were 1727 cases of late AMD (1151 neovascular, 384 geographic atrophy, and 192 mixed [neovascular AMD and geographic atrophy]) and 1153 controls. Early AMD cases (n = 574) were included only from the EUREYE Study. Data analysis was performed from August 1 to November 30, 2016. Four common single-nucleotide polymorphisms (rs1205, rs1130864, rs1800947, and rs3093077) were selected based on demonstrated influence on circulating CRP concentrations in the literature. In one study, genotyping of rs3093077 failed, and rs1800947 was typed in only 1 study.

Main Outcomes and Measures

A genetic multiplicative model was used for the association of single-nucleotide polymorphisms with late AMD adjusted for age and sex.

Results

Among the 1727 patients with late AMD, the mean (SD) age was 78.7 (7.4) years, and 668 (38.7%) were men. The mean (SD) age of the controls was 74.9 (7.0) years, and 510 (44.2%) were men. In the pooled results of all 3 studies, neither rs1205 (odds ratio [OR], 0.99; 95% CI, 0.86-1.14) nor rs1130864 (OR, 0.96; 95% CI, 0.83-1.11) was associated with late AMD. For geographic atrophy, rs1205 had an OR of 0.91 (95% CI, 0.74-1.13) and rs1130864 had an OR of 0.94 (95% CI, 0.76-1.16). For neovascular AMD, rs1205 had an OR of 1.01 (95% CI, 0.87-1.19) and rs1130864 had an OR of 0.99 (95% CI, 0.84-1.16). There was no association of rs3093077 and rs1800947 with late AMD or any late AMD phenotype. There were no significant findings for early AMD.

Conclusions and Relevance

Our results do not support a causal association between CRP concentrations and AMD.

Detailed Clinical Phenotype and Molecular Genetic Findings in CLN3-Associated Isolated Retinal Degeneration

Importance

Mutations in genes traditionally associated with syndromic retinal disease are increasingly found to cause nonsyndromic inherited retinal degenerations. Mutations in CLN3 are classically associated with juvenile neuronal ceroid lipofuscinosis, a rare neurodegenerative disease with early retinal degeneration and progressive neurologic deterioration, but have recently also been identified in patients with nonsyndromic inherited retinal degenerations. To our knowledge, detailed clinical characterization of such cases has yet to be reported.

Objective

To provide detailed clinical, electrophysiologic, structural, and molecular genetic findings in nonsyndromic inherited retinal degenerations associated with CLN3 mutations.

Design, Setting, and Participants

A multi-institutional case series of 10 patients who presented with isolated nonsyndromic retinal disease and mutations in CLN3. Patient ages ranged from 16 to 70 years; duration of follow-up ranged from 3 to 29 years.

Main Outcomes and Measures

Longitudinal clinical evaluation, including full ophthalmic examination, multimodal retinal imaging, perimetry, and electrophysiology. Molecular analyses were performed using whole-genome sequencing or whole-exome sequencing. Electron microscopy studies of peripheral lymphocytes and CLN3 transcript analysis with polymerase chain reaction amplification were performed in a subset of patients.

Results

There were 7 females and 3 males in this case series, with a mean (range) age at last review of 37.1 (16-70) years. Of the 10 patients, 4 had a progressive late-onset rod-cone dystrophy, with a mean (range) age at onset of 29.7 (20-40) years, and 6 had an earlier onset rod-cone dystrophy, with a mean (range) age at onset of 12.1 (7-17) years. Ophthalmoscopic examination features included macular edema, mild intraretinal pigment migration, and widespread atrophy in advanced disease. Optical coherence tomography imaging demonstrated significant photoreceptor loss except in patients with late-onset disease who had a focal preservation of the ellipsoid zone and outer nuclear layer in the fovea. Electroretinography revealed a rod-cone pattern of dysfunction in 6 patients and were completely undetectable in 2 patients. Six novel CLN3 variants were identified in molecular analyses.

Conclusions and Relevance

This report describes detailed clinical, imaging, and genetic features of CLN3-associated nonsyndromic retinal degeneration. The age at onset and natural progression of retinal disease differs greatly between syndromic and nonsyndromic CLN3 disease, which may be associated with genotypic differences.