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There is a lack of studies which seek to discern disease expression in patients with mutations that alter retinal ceramide metabolism, specifically in the ceramide kinase like (CERKL) gene. This cross-sectional case series reports a novel phenotypic manifestation of CERKL-associated retinopathy. Four unrelated patients with homozygous CERKL mutations underwent a complete ocular exam, spectral-domain optical coherence tomography, short-wavelength fundus autofluorescence (SW-AF), quantitative autofluorescence (qAF), and full-field electroretinogram (ffERG). Decreased visual acuity and early-onset maculopathy were present in all patients. All four patients had extensive hyperautofluorescent foci surrounding an area of central atrophy on SW-AF imaging, which has not been previously characterized. An abnormal spatial distribution of qAF signal was seen in one patient, and abnormally elevated qAF8 signal in another patient. FfERG recordings showed markedly attenuated rod and cone response in all patients. We conclude that these patients exhibit several features that, collectively, may warrant screening of CERKL as a first candidate: early-onset maculopathy, severe generalized retinal dysfunction, peripheral lacunae, intraretinal pigment migration, and hyperautofluorescent foci on SW-AF.

PURPOSE To describe the complex, overlapping phenotype expressed in a two generation family harboring pathogenic mutations in the ABCA4 and GPR143 genes. METHODS Clinical evaluation of a two generation family included quantitative autofluorescence imaging (qAF, 488-nm excitation) using a modified confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for varying laser power detector sensitivity, spectral-domain optical coherence tomography, and full-field ERG testing. Complete sequencing of the ABCA4 and GPR143 genes was carried out in each individual. RESULTS Affected individuals presented with bull's eye lesions and qAF levels above the 95% confidence interval for healthy eyes; full-field ERG revealed no generalized rod dysfunction but mild implicit time delays in cone responses. Complete sequencing of the ABCA4 gene revealed two disease-causing mutations, p.L541P and p.G1961E; and mutational phase was confirmed in each unaffected parent. Further examination in the affected patients revealed a peripheral "mud-splattered" pattern of hypopigmented RPE after which sequencing of GPR143 revealed a novel missense variant, p.Y157C. The GPR143 variant segregated from the father who did not exhibit any indications of retinal disease with the exception of an abnormal near-infrared autofluorescence (NIR-AF) signal distribution in the macula. CONCLUSIONS An individual carrying both ABCA4 and GPR143 disease-causing mutations can express a complex, overlapping phenotype associated with both Stargardt disease and X-linked ocular albinism (OA1). The absence of OA1-related disease changes (with the exception of NIR-AF changes associated with melanin distribution) in the father may be indicative of mild expressivity or variable gene penetrance.

Cis-regulatory elements (CREs) orchestrate the dynamic and diverse transcriptional programs that assemble the human central nervous system (CNS) during development and maintain its function throughout life. Genetic variation within CREs plays a central role in phenotypic variation in complex traits including the risk of developing disease. However, the cellular complexity of the human brain has largely precluded the identification of functional regulatory variation within the human CNS. We took advantage of the retina, a well-characterized region of the CNS with reduced cellular heterogeneity, to establish a roadmap for characterizing regulatory variation in the human CNS. This comprehensive resource of tissue-specific regulatory elements, transcription factor binding, and gene expression programs in three regions of the human visual system (retina, macula, retinal pigment epithelium/choroid) reveals features of regulatory element evolution that shape tissue-specific gene expression programs and defines the regulatory elements with the potential to contribute to mendelian and complex disorders of human vision.

International audience; In 2016, during a major Zika virus (ZIKV) outbreak in Maracaibo, Venezuela, a 49-year-old woman and an unrelated 4-year-old boy developed bilateral optic neuritis 2-3 weeks after presenting an acute febrile illness characterized by low-grade fever, rash and myalgia [1]. Both patients presented sudden, painless bilateral loss of vision with no corneal or uveal abnormalities. Fundoscopic examination revealed oedema of the optic nerve and optic disc pallor. Optical coherence tomography confirmed bilateral optic nerve head swelling in the case of the adult, but it was not carried out in the child. Automated perimetry performed in the adult revealed bilateral diffuse visual field loss. Magnetic resonance imaging of the brain in both cases was unremarkable. Both patients were diagnosed with bilateral optic neuritis of possible infectious or parainfectious origin. Differential diagnoses that were considered and subsequently discarded included arteritic and non-arteritic ischaemic optic neuropathy, and brain disorders such as multiple sclerosis and brain tumours. Both patients were seropositive for anti-ZIKV IgG and seronegative for anti-ZIKV IgM. In addition, both patients were positive for anti-dengue virus (DENV) IgG for all four DENV serotypes. Management included intravenous methylprednisolone for 3 days, followed by oral prednisolone for 11 days. Although the patients presented a modest improvement in their vision, they continued to have visual impairment after several months of follow-up [1]. DISCUSSION Correct Answer: 4. These complications can lead to permanent visual impairment. ZIKV is a mosquito-borne RNA virus belonging to the genus Flavivirus of the family Flaviviridae [2]. The classical QUESTION Which of the following statements is accurate about non-congenital severe ocular complications of Zika virus (ZIKV) infection? ANSWER OPTIONS 1. They are unique to ZIKV infection and readily distinguish-able from complications caused by other flaviviruses. 2. Serious ocular complications are related to the severity of the acute exanthematous illness. 3. The diagnosis can be conclusively established by detecting anti-Zika IgM and/or IgG in the patient's serum. 4. These complications can lead to permanent visual impairment. 5. There is specific treatment for ocular manifestations caused by ZIKV infection. This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited. 1 clinical picture of ZIKV infection includes fever, exanthema, headache and conjunctivitis. The most common non-congenital, ocular manifestation of ZIKV infection is a self-limiting conjunctivitis. Serious ocular complications have been reported for other arboviruses, such as DENV [3-20], chikungunya virus [21-24], West Nile virus [25-39] and Rift Valley fever virus [9-11, 40] (Table 1). To date, there is no specific ocular lesion that is pathognomonic for ZIKV infection [41-45]. Non-congenital ocular complications are infrequent, but serious, consequences of ZIKV and other arboviral infections. The complications may appear at the end of the acute febrile illness, but more commonly occur within 2 weeks to 1 month after the onset of symptoms. There is no evidence to suggest that serious ocular complications correlate with the severity of the acute febrile illness. One study, however, found that the white cell count and serum albumin are significant predictors of ocular complications of DENV [46]. Serological testing for arboviral diseases should be performed in all patients with ocular complications and a recent history of acute febrile exanthematous infection, who live, or have travelled to, endemic regions. The presence of IgM to ZIKV strongly suggests that the ocular manifestation is associated with this virus. A causative aetiology, however, can only be established by documenting the presence of the virus in body fluids, either by cell culture or by PCR. It should be noted that other viruses, such as herpes simplex virus and human immunodeficiency virus, can also cause retinal damage and optic neuritis. Furthermore, as in the cases presented here, the diagnosis is complicated by cross-reactivity among flaviviruses, and by the co-circulation of arboviruses. Most patients with ocular complications of arboviral infections recover completely. Nevertheless, physicians should be aware that a small percentage of patients have permanent damage with long-life visual impairment. There is no specific or established treatment for optic neuritis caused by any arboviral infection. Systemic steroids may be used to reduce inflammation and resulting ischae-mia. Corticosteroids have been used in combination with acyclovir to treat chikungunya-associated optic neuritis, but efficacy has not been proven [47].

Structural variation and single-nucleotide variation of the complement factor H (CFH) gene family underlie several complex genetic diseases, including age-related macular degeneration (AMD) and atypical hemolytic uremic syndrome (AHUS). To understand its diversity and evolution, we performed high-quality sequencing of this ∼360-kbp locus in six primate lineages, including multiple human haplotypes. Comparative sequence analyses reveal two distinct periods of gene duplication leading to the emergence of four CFH-related (CFHR) gene paralogs (CFHR2 and CFHR4 ∼25-35 Mya and CFHR1 and CFHR3 ∼7-13 Mya). Remarkably, all evolutionary breakpoints share a common ∼4.8-kbp segment corresponding to an ancestral CFHR gene promoter that has expanded independently throughout primate evolution. This segment is recurrently reused and juxtaposed with a donor duplication containing exons 8 and 9 from ancestral CFH, creating four CFHR fusion genes that include lineage-specific members of the gene family. Combined analysis of >5,000 AMD cases and controls identifies a significant burden of a rare missense mutation that clusters at the N terminus of CFH [P = 5.81 × 10-8, odds ratio (OR) = 9.8 (3.67-Infinity)]. A bipolar clustering pattern of rare nonsynonymous mutations in patients with AMD (P 2,400 individuals reveals five recurrent rearrangement breakpoints that show variable frequency among AMD cases and controls. These data suggest a dynamic and recurrent pattern of mutation critical to the emergence of new CFHR genes but also in the predisposition to complex human genetic disease phenotypes.

Introduction. Although the current Zika virus (ZIKV) epidemic is a major public health concern, most reports have focused on congenital ZIKV syndrome, its most devastating manifestation. Severe ocular complications associated with ZIKV infections and possible pathogenetic factors are rarely described. Here, we describe three Venezuelan patients who developed severe ocular manifestations following ZIKV infections. We also analyse their serological response to ZIKV and dengue virus (DENV). Case presentation. One adult with bilateral optic neuritis, a child of 4 years of age with retrobulbar uveitis and a newborn with bilateral congenital glaucoma had a recent history of an acute exanthematous infection consistent with ZIKV infection. The results of ELISA tests indicated that all patients were seropositive for ZIKV and four DENV serotypes. Conclusion. Patients with ZIKV infection can develop severe ocular complications. Anti-DENV antibodies from previous infections could play a role in the pathogenesis of these complications. Well-designed epidemiological studies are urgently needed to measure the risk of ZIKV ocular complications and confirm whether they are associated with the presence of anti-flaviviral antibodies.

Purpose To describe a distinct phenotypic outcome of outer retinal degeneration in a cohort of genetically confirmed patients with recessive Stargardt disease (STGD1). Design Retrospective case series. Methods Twelve patients, who were clinically diagnosed with STGD1 and exhibited a unique degenerative phenotype, were included in the study. Two disease-causing mutations were found in all patients by direct sequencing of the ABCA4 gene. Clinical characterization of patients were defined on fundus photographs, autofluorescence images (488-nm and 532-nm excitation), spectral-domain optical coherence tomography (SD-OCT), and full-field electroretinogram (ffERG) testing. Results Mean age at initial presentation was 67.8 years and reported age of symptomatic onset was 14.1 years (mean disease duration = 53.8 years). Best-corrected visual acuity ranged from 20/400 to hand motion. All patients exhibited advanced degeneration across the posterior pole resulting in a reflectively pale, blonde fundus owing to unobstructed exposure of the underlying sclera. SD-OCT revealed complete loss of the outer retinal bands (external limiting membrane, ellipsoid zone, interdigitation zone, and retinal pigment epithelium) and choroidal layers. Scotopic and photopic waveforms on ffERG were nonrecordable or severely attenuated in 8 patients who were tested. Conclusions Widespread scleral exposure is a clinical outcome in a subset of STGD1 following a long duration of disease progression (∼50 years). The blonde fundus in such cases may exhibit phenotypic overlap and shared therapeutic implications with other aggressive chorioretinal dystrophies such as end-stage choroideremia, gyrate atrophy, or RPE65-Leber congenital amaurosis.

Sequence analysis of the coding regions and splice site sequences in inherited retinal diseases is not able to uncover ∼40% of the causal variants. Whole-genome sequencing can identify most of the non-coding variants, but their interpretation is still very challenging, in particular when the relevant gene is expressed in a tissue-specific manner. Deep-intronic variants in ABCA4 have been associated with autosomal-recessive Stargardt disease (STGD1), but the exact pathogenic mechanism is unknown. By generating photoreceptor precursor cells (PPCs) from fibroblasts obtained from individuals with STGD1, we demonstrated that two neighboring deep-intronic ABCA4 variants (c.4539+2001G>A and c.4539+2028C>T) result in a retina-specific 345-nt pseudoexon insertion (predicted protein change: p.Arg1514Leufs∗36), likely due to the creation of exonic enhancers. Administration of antisense oligonucleotides (AONs) targeting the 345-nt pseudoexon can significantly rescue the splicing defect observed in PPCs of two individuals with these mutations. Intriguingly, an AON that is complementary to c.4539+2001G>A rescued the splicing defect only in PPCs derived from an individual with STGD1 with this but not the other mutation, demonstrating the high specificity of AONs. In addition, a single AON molecule rescued splicing defects associated with different neighboring mutations, thereby providing new strategies for the treatment of persons with STGD1. As many genes associated with human genetic conditions are expressed in specific tissues and pre-mRNA splicing may also rely on organ-specific factors, our approach to investigate and treat splicing variants using differentiated cells derived from individuals with STGD1 can be applied to any tissue of interest.

Over 800 mutations in the ABCA4 gene cause autosomal recessive Stargardt disease. Due to extensive genetic heterogeneity, observed variant-associated phenotypes can manifest tremendous variability of expression. Furthermore, the high carrier frequency of pathogenic ABCA4 alleles in the general population (~1:20) often results in pseudo-dominant inheritance patterns further complicating the diagnosis and characterization of affected individuals. This study describes a genotype/phenotype analysis of an unusual family with multiple macular disease phenotypes spanning across two generations and segregating four distinct ABCA4 mutant alleles. Complete sequencing of ABCA4 discovered two known missense mutations, p.C54Y and p.G1961E. Array comparative genomic hybridization revealed a large novel deletion combined with a small insertion, c.6148-698_c.6670del/insTGTGCACCTCCCTAG, and complete sequencing of the entire ABCA4 genomic locus uncovered a new deep intronic variant, c.302+68C>T. Patients with the p.G1961E mutation had the mildest, confined maculopathy phenotype with peripheral flecks while those with all other mutant allele combinations exhibited a more advanced stage of generalized retinal and choriocapillaris atrophy. This family epitomizes the clinical and genetic complexity of ABCA4-associated diseases. It contained variants from all classes of mutations, in the coding region, deep intronic, both single nucleotide variants (SNV) and copy number variants (CNV) that accounted for varying phenotypes segregating in an apparent dominant fashion. Unequivocally defining disease-associated alleles in the ABCA4 locus requires a multifaceted approach that includes advanced mutation detection methods and a thorough analysis of clinical phenotypes.

Purpose To describe the clinical and molecular characteristics of patients with childhood-onset Stargardt disease (STGD). Design Retrospective case series. Participants Forty-two patients who were diagnosed with STGD in childhood at a single institution between January 2001 and January 2012. Methods A detailed history and a comprehensive ophthalmic examination were undertaken, including color fundus photography, autofluorescence imaging, spectral-domain optical coherence tomography (SD-OCT), and pattern and full-field electroretinograms. The entire coding region and splice sites of ABCA4 were screened using a next-generation, sequencing-based strategy. The molecular genetic findings of childhood-onset STGD patients were compared with those of adult-onset patients. Main Outcome Measures Clinical, imaging, electrophysiologic, and molecular genetic findings. Results The median ages of onset and the median age at baseline examination were 8.5 (range, 3–16) and 12.0 years (range, 7-16), respectively. The median baseline logarithm of the minimum angle of resolution visual acuity was 0.74. At baseline, 26 of 39 patients (67%) with available photographs had macular atrophy with macular/peripheral flecks; 11 (28%) had macular atrophy without flecks; 1 (2.5%) had numerous flecks without macular atrophy; and 1 (2.5%) had a normal fundus appearance. Flecks were not identified at baseline in 12 patients (31%). SD-OCT detected foveal outer retinal disruption in all 21 patients with available images. Electrophysiologic assessment demonstrated retinal dysfunction confined to the macula in 9 patients (36%), macular and generalized cone dysfunction in 1 subject (4%), and macular and generalized cone and rod dysfunction in 15 individuals (60%). At least 1 disease-causing ABCA4 variant was identified in 38 patients (90%), including 13 novel variants; ≥2 variants were identified in 34 patients (81%). Patients with childhood-onset STGD more frequently harbored 2 deleterious variants (18% vs 5%) compared with patients with adult-onset STGD. Conclusions Childhood-onset STGD is associated with severe visual loss, early morphologic changes, and often generalized retinal dysfunction, despite often having less severe fundus abnormalities on examination. One third of children do not have flecks at presentation. The relatively high proportion of deleterious ABCA4 variants supports the hypothesis that earlier onset disease is often owing to more severe variants in ABCA4 than those found in adult-onset disease.

Purpose Quantitative fundus autofluorescence (qAF) and spectral-domain optical coherence tomography (SD OCT) were performed in patients with bull's-eye maculopathy (BEM) to identify phenotypic markers that can aid in the differentiation of ABCA4 -associated and non– ABCA4 -associated disease. Design Prospective cross-sectional study at an academic referral center. Subjects Thirty-seven BEM patients (age range, 8–60 years) were studied. All patients exhibited a localized macular lesion exhibiting a smooth contour and qualitatively normal-appearing surrounding retina without flecks. Control values consisted of previously published data from 277 healthy subjects (374 eyes; age range, 5–60 years) without a family history of retinal dystrophy. Methods Autofluorescence (AF) images (30°, 488-nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The grey levels (GLs) from 8 circularly arranged segments positioned at an eccentricity of approximately 7° to 9° in each image were calibrated to the reference (0 GL), magnification, and normative optical media density to yield qAF. In addition, horizontal SD OCT images through the fovea were obtained. All patients were screened for ABCA4 mutations using the ABCR600 microarray, next-generation sequencing, or both. Main Outcome Measures Quantitative AF, correlations between AF and SD OCT, and genotyping for ABCA4 variants. Results ABCA4 mutations were identified in 22 patients, who tended to be younger (mean age, 21.9±8.3 years) than patients without ABCA4 mutations (mean age, 42.1±14.9 years). Whereas phenotypic differences were not obvious on the basis of qualitative fundus AF and SD OCT imaging, with qAF, the 2 groups of patients were clearly distinguishable. In the ABCA4 -positive group, 37 of 41 eyes (19 of 22 patients) had qAF 8 of more than the 95% confidence interval for age. Conversely, in the ABCA4 -negative group, 22 of 26 eyes (13 of 15 patients) had qAF 8 within the normal range. Conclusions The qAF method can differentiate between ABCA4 -associated and non– ABCA4 -associated BEM and may guide clinical diagnosis and genetic testing.

Variants in the complement factor H gene (CFH) are associated with age-related macular degeneration (AMD). CFH and five CFH-related genes (CFHR1-5) lie within the regulators of complement activation (RCA) locus on chromosome 1q32. Aims and Methods. In this study, the structural and evolutionary relationships between these genes and AMD was refined using a combined genetic, molecular and immunohistochemical approach.We identify and characterize a large, common deletion that encompasses both the CFHR1 and CFHR3 genes. CFHR1, an abundant serum protein, is absent in subjects homozygous for the deletion. Genotyping analyses of AMD cases and controls from two cohorts demonstrates that deletion homozygotes comprise 1.1% of cases and 5.7% of the controls (chi-square=32.8; P= 1.6 E-09). CFHR1 and CFHR3 transcripts are abundant in liver, but undetectable in the ocular retinal pigmented epithelium/choroid complex. AMD-associated CFH/CFHR1/CFHR3 haplotypes are widespread in human populations.The absence of CFHR1 and/or CFHR3 may account for the protective effects conferred by some CFH haplotypes. Moreover, the high frequencies of the 402H allele and the delCFHR1/CFHR3 alleles in African populations suggest an ancient origin for these alleles. The considerable diversity accumulated at this locus may be due to selection, which is consistent with an important role for the CFHR genes in innate immunity.

BackgroundVariation in theABCA4gene is causal for, or associated with, a wide range of phenotypes from early onset Mendelian retinal dystrophies to late-onset complex disorders such as age-related macular degeneration (AMD). Despite substantial progress in determining the causal genetic variation, even complete sequencing of the entire open reading frame and splice sites ofABCA4identifies biallelic mutations in only 60%–70% of cases; 20%–25% remain with one mutation and no mutations are found in 10%–15% of cases with clinically confirmed ABCA4 disease. This study was designed to identify missing causal variants specifically in monoallelic cases of ABCA4 disease.MethodsDirect sequencing and analysis were performed in a large familial ABCA4 disease cohort of predominately European descent (n=643). Patient phenotypes were assessed from clinical and retinal imaging data.ResultsWe determined that a hypomorphicABCA4variant c.5603A>T (p.Asn1868Ile), previously considered benign due to high minor allele frequency (MAF) (~7%) in the general population, accounts for 10% of the disease, >50% of the missing causal alleles in monoallelic cases, ~80% of late-onset cases and distinguishes ABCA4 disease from AMD. It results in a distinct clinical phenotype characterised by late-onset of symptoms (4th decade) and foveal sparing (85%). Intragenic modifying effects involving this variant and another, c.2588G>C (p.Gly863Ala) allele, were also identified.ConclusionsThese findings substantiate the causality of frequent missense variants and their phenotypic outcomes as a significant contribution to ABCA4 disease, particularly the late-onset phenotype, and its clinical variation. They also suggest a significant revision of diagnostic screening and assessment ofABCA4variation in aetiology of retinal diseases.

Pre-mRNA splicing factors play a fundamental role in regulating transcript diversity both temporally and spatially. Genetic defects in several spliceosome components have been linked to a set of non-overlapping spliceosomopathy phenotypes in humans, among which skeletal developmental defects and non-syndromic retinitis pigmentosa (RP) are frequent findings. Here we report that defects in spliceosome-associated protein CWC27 are associated with a spectrum of disease phenotypes ranging from isolated RP to severe syndromic forms. By whole-exome sequencing, recessive protein-truncating mutations in CWC27 were found in seven unrelated families that show a range of clinical phenotypes, including retinal degeneration, brachydactyly, craniofacial abnormalities, short stature, and neurological defects. Remarkably, variable expressivity of the human phenotype can be recapitulated in Cwc27 mutant mouse models, with significant embryonic lethality and severe phenotypes in the complete knockout mice while mice with a partial loss-of-function allele mimic the isolated retinal degeneration phenotype. Our study describes a retinal dystrophy-related phenotype spectrum as well as its genetic etiology and highlights the complexity of the spliceosomal gene network.

The purpose of our study was to investigate morpho-functional features of the preferred retinal location (PRL) and the transition zone (TZ) in a series of patients with recessive Stargardt disease (STGD1). Fifty-two STGD1 patients with at least one ABCA4 mutation, atrophy of the central macula (MA) and an eccentric PRL were recruited for the study. Microperimetry, fundus autofluorescence (FAF), spectral-domain optical coherence tomography (SD-OCT) were performed. The location and stability of the PRL along with the associated FAF pattern and visual sensitivities were determined and compared to the underlying retinal structure. The mean visual sensitivity of the PRLs for the 52 eyes was 10.76 +/- 3.70 dB. For the majority of eyes, PRLs were associated with intact ellipsoid zone (EZ) bands and qualitatively normal FAF patterns. In 17 eyes (32.7%) the eccentric PRL was located at the edge of the MA. In 35 eyes (67.3%) it was located at varying distances from the border of the MA with a TZ between the PRL and the MA. The TZ was associated with decreased sensitivity values (5.92 +/- 4.69 dB) compared to PRLs (p

PURPOSE Short-wavelength (SW) fundus autofluorescence (AF) is considered to originate from lipofuscin in retinal pigment epithelium (RPE) and near-infrared (NIR) AF from melanin. In patients with recessive Stargardt disease (STGD1), we correlated SW-AF and NIR-AF with structural information obtained by spectral-domain optical coherence tomography (SD-OCT). METHODS Twenty-four STGD1 patients (45 eyes; age 8 to 61 years) carrying confirmed disease-associated ABCA4 mutations were studied prospectively. Short-wavelength AF, NIR-AF, and SD-OCT images were acquired. RESULTS Five phenotypes were identified according to features of the central lesion and extent of fundus change. Central zones of reduced NIR-AF were typically larger than areas of diminished SW-AF and reduced NIR-AF usually approximated areas of ellipsoid zone (EZ) loss identified by SD-OCT (group 1; r, 0.93, P < 0.0001). In patients having a central lesion with overlapping parafoveal rings of increased NIR-AF and SW-AF (group 3), the extent of EZ loss was strongly correlated with the inner diameter of the NIR-AF ring (r, 0.89, P < 0.0001) and the eccentricity of the outer border of the NIR-AF ring was greater than that of the SW-AF ring. CONCLUSIONS Lesion areas were more completely delineated in NIR-AF images than with SW-AF. In most cases, EZ loss was observed only at locations where NIR-AF was reduced or absent, indicating that RPE cell atrophy occurs in advance of photoreceptor cell degeneration. Because SW-AF was often increased within the central area of EZ disruption, degenerating photoreceptor cells may produce lipofuscin at accelerated levels. Consideration is given to mechanisms underlying hyper-NIR-AF in conjunction with increased SW-AF.

Autosomal recessive Stargardt disease (STGD1) is caused by hundreds of mutations in the ABCA4 gene, which are often specific to racial and ethnic groups. Here, we investigated the ABCA4 variation and their phenotypic expression in a cohort of 44 patients of African American descent, a previously under-characterized racial group. Patients were screened for mutations in ABCA4 by next-generation sequencing and array-comparative genomic hybridization (aCGH), followed by analyses for pathogenicity by in silico programs. Thorough ophthalmic examination was performed on all patients. At least two (expected) disease-causing alleles in the ABCA4 gene were identified in 27 (61.4%) patients, one allele in 11 (25%) patients, and no ABCA4 mutations were found in six (13.6%) patients. Altogether, 39 different disease-causing ABCA4 variants, including seven new, were identified on 65 (74%) chromosomes, most of which were unique for this racial group. The most frequent ABCA4 mutation in this cohort was c.6320G>A (p.(R2107H)), representing 19.3% of all disease-associated alleles. No large copy number variants were identified in any patient. Most patients reported later onset of symptoms. In summary, the ABCA4 mutation spectrum in patients of West African descent differs significantly from that in patients of European descent, resulting in a later onset and “milder” disease.

To investigate psychophysical thresholds in Stargardt disease with the full-field stimulus test (FST).Visual acuity, spectral domain optical coherence tomography, full-field electroretinogram, and FST measurements were made in 1 eye of 24 patients with Stargardt disease. Dark-adapted rod FST thresholds were measured with short-wavelength stimuli, and cone FST thresholds were obtained from the cone plateau phase of dark adaptation using long-wavelength stimuli. Correlation coefficients were calculated for FST thresholds versus macular thickness, visual acuity, and electroretinogram amplitudes.The Stargardt disease patients' FST cone thresholds correlated significantly with visual acuity, macular thickness, and electroretinogram cone response amplitudes (all P0.01). The patients' FST rod thresholds correlated with electroretinogram rod response amplitudes (P0.01) but not macular thickness (P = 0.05). All patients with Stargardt disease with flecks confined to the macula, and most of the patients with flecks extending outside of the macula had normal FST thresholds. All patients with extramacular atrophic changes had elevated FST cone thresholds and most had elevated FST rod thresholds.Full-field stimulus test rod and cone threshold elevation in patients with Stargardt disease correlated well with measures of structure and function, as well as ophthalmoscopic retinal appearance. The Full-field stimulus test appears to be a useful tool for assessing rod and cone function in Stargardt disease.

Stargardt disease is a recessively inherited form of macular dystrophy that predominantly causes loss of central vision in approximately 1 in 8,000 to 1 in 10,000 people in the United States.1 Although it is commonly associated with a juvenile onset, patients may present into adulthood. Described by Karl Stargardt in 1909, the characteristic findings of Stargardt disease include the presence of yellow flecks in the macula or throughout the posterior pole of the fundus.2,3 Patients with Stargardt disease may present with or without an atrophic-appearing macular lesion depending on the level of severity of the disease and can be classified according to the distribution and stage of their fundus flecks.3 Other classification systems exist, including one involving the degree of functional loss using electrophysiologic testing.4 With the emergence of Stargardt treatment trials, it has become of paramount importance to identify sensitive measurements of retinal structure and function that can be used as effective clinical outcome measures. In Stargardt disease, noninvasive retinal imaging, with infrared scanning laser ophthalmoscopy (SLO) and short-wavelength autofluorescence (SW-AF) technology, has allowed for improved visualization of disease-related fundus changes that may be otherwise difficult to see funduscopically. The development of spectral-domain optical coherence tomography (SD-OCT) coupled with infrared-SLO imaging offers confocal and cross-sectional analyses of the retina, allowing an improved clinical assessment of patients with Stargardt disease.5 Additionally, functional testing, made possible with microperimetry (MP), facilitates a comparison with structural retinal abnormalities. In this study, patients with Stargardt disease were evaluated using infrared-SLO imaging, SD-OCT, SW-AF, macular MP, fundus photography, and full-field electroretinograms (ERG). We compared the structural abnormalities seen on infrared-SLO with those observed with SW-AF and SD-OCT, identifying any possible redundancy in the use of these imaging modalities or potentially different information provided by each test. Associations of each test were also made with functional measurements obtained by macular MP.

Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10 337 cases and 11 174 controls (OR = 1.10; P-value = 3.79 × 10(-5)). Thus, it appears that rare and common variants in a single gene--FBN2--can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.

To document longitudinal fundus autofluorescence (FAF) and electroretinogram (ERG) findings in a family with cone–rod dystrophy (CRD) caused by a novel missense mutation (D100G) in the GUCA1A gene. Observational case series. Three family members 26–49 years old underwent complete clinical examinations. In all patients, funduscopic findings showed intraretinal pigment migration, loss of neurosensory retinal pigment epithelium, and macular atrophy. FAF imaging revealed the presence of a progressive hyperautofluorescent ring around a hypoautofluorescent center corresponding to macular atrophy. Full-field ERGs showed a more severe loss of cone than rod function in each patient. Thirty-hertz flicker responses fell far below normal limits. Longitudinal FAF and ERG findings in one patient suggested progressive CRD. Two more advanced patients exhibited reduced rod response consistent with disease stage. Direct sequencing of the GUCA1A gene revealed a new missense mutation, p.Asp100Gly (D100G), in each patient. Patients with autosomal dominant CRD caused by a D100G mutation in GUCA1A exhibit progressive vision loss early within the first decade of life identifiable by distinct ERG characteristics and subsequent genetic testing.

Objective To provide a comprehensive overview of all detected mutations in the ABCA4 gene in Spanish families with autosomal recessive retinal disorders, including Stargardt's disease (arSTGD), cone-rod dystrophy (arCRD), and retinitis pigmentosa (arRP), and to assess genotype-phenotype correlation and disease progression in 10 years by considering the type of variants and age at onset. Design Case series. Participants A total of 420 unrelated Spanish families: 259 arSTGD, 86 arCRD, and 75 arRP. Methods Spanish families were analyzed through a combination of ABCR400 genotyping microarray, denaturing high-performance liquid chromatography, and high-resolution melting scanning. Direct sequencing was used as a confirmation technique for the identified variants. Screening by multiple ligation probe analysis was used to detect possible large deletions or insertions in the ABCA4 gene. Selected families were analyzed further by next generation sequencing. Main Outcome Measures DNA sequence variants, mutation detection rates, haplotypes, age at onset, central or peripheral vision loss, and night blindness. Results Overall, we detected 70.5% and 36.6% of all expected ABCA4 mutations in arSTGD and arCRD patient cohorts, respectively. In the fraction of the cohort where the ABCA4 gene was sequenced completely, the detection rates reached 73.6% for arSTGD and 66.7% for arCRD. However, the frequency of possibly pathogenic ABCA4 alleles in arRP families was only slightly higher than that in the general population. Moreover, in some families, mutations in other known arRP genes segregated with the disease phenotype. Conclusions An increasing understanding of causal ABCA4 alleles in arSTGD and arCRD facilitates disease diagnosis and prognosis and also is paramount in selecting patients for emerging clinical trials of therapeutic interventions. Because ABCA4 -associated diseases are evolving retinal dystrophies, assessment of age at onset, accurate clinical diagnosis, and genetic testing are crucial. We suggest that ABCA4 mutations may be associated with a retinitis pigmentosa–like phenotype often as a consequence of severe (null) mutations, in cases of long-term, advanced disease, or both. Patients with classical arRP phenotypes, especially from the onset of the disease, should be screened first for mutations in known arRP genes and not ABCA4 . Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose The accuracy of predicting conversion from early-stage age-related macular degeneration (AMD) to the advanced stages of choroidal neovascularization (CNV) or geographic atrophy (GA) was evaluated to determine whether inclusion of clinically relevant genetic markers improved accuracy beyond prediction using phenotypic risk factors alone. Design Cohort study. Participants White, non-Hispanic subjects participating in the Age-Related Eye Disease Study (AREDS) sponsored by the National Eye Institute consented to provide a genetic specimen. Of 2415 DNA specimens available, 940 were from disease-free subjects and 1475 were from subjects with early or intermediate AMD. Methods DNA specimens from study subjects were genotyped for 14 single nucleotide polymorphisms (SNPs) in genes shown previously to associate with CNV: ARMS2 , CFH , C3 , C2 , FB , CFHR4 , CFHR5, and F13B . Clinical demographics and established disease associations, including age, sex, smoking status, body mass index (BMI), AREDS treatment category, and educational level, were evaluated. Four multivariate logistic models (phenotype; genotype; phenotype + genotype; and phenotype + genotype + demographic + environmental factors) were tested using 2 end points (CNV, GA). Models were fitted using Cox proportional hazards regression to use time-to-disease onset data. Main Outcome Measures Brier score (measure of accuracy) was used to identify the model with the lowest prediction error in the training set. The most accurate model was subjected to independent statistical validation, and final model performance was described using area under the receiver operator curve (AUC) or C-statistic. Results The CNV prediction models that combined genotype with phenotype with or without age and smoking revealed superior performance (C-statistic = 0.96) compared with the phenotype model based on the simplified severity scale and the presence of CNV in the nonstudy eye (C-statistic = 0.89; P ARMS2 genotype had less of an impact on the prediction of GA compared with CNV. Conclusions Inclusion of genotype assessment improves CNV prediction beyond that achievable with phenotype alone and may improve patient management. Separate assessments should be used to predict progression to CNV and GA because genetic markers and smoking status do not equally predict both end points. Financial Disclosure(s) Proprietary or commercial disclosure may be found after the references.

Age-related macular degeneration (AMD) is a common cause of blindness in older individuals. To accelerate the understanding of AMD biology and help design new therapies, we executed a collaborative genome-wide association study, including >17,100 advanced AMD cases and >60,000 controls of European and Asian ancestry. We identified 19 loci associated at P

Variants in the ABCA4 gene are the most common cause of juvenile-onset blindness affecting close to 1 in 10 000 people worldwide. Disease severity varies largely according to genotype, which can be specific to ethnic and racial groups. Here we investigate the spectrum of ABCA4 variation and its phenotypic expression in 38 patients of South Asian descent, notably from India, Pakistan, Bangladesh and Sri Lanka. Sequencing of all exons and flanking intronic sequences of ABCA4 revealed disease-causing variants in all patients: 3 in 2.6%, 2 in 81.6% and 1 in 15.8%. Altogether, 36 distinct variants were identified, including 9 previously not described. The most frequent variant c.5882G>A, p.(G1961E) was found in half the patients, the highest ever reported in a single study cohort. The South Asian founder variant c.859-9T>C was identified along with other founder variants ascribed to Danish, Chinese, Mexican and African patients. Patients carrying c.5882G>A, p.(G1961E) exhibited a consistently confined disease phenotype, normal quantitative autofluorescence (qAF) levels and preserved full-field ERG (ffERG) while c.859-9T>C resulted in widespread disease, significantly elevated qAF and reduced to non-detectable ffERG. South Asian patients present with a relatively unique ABCA4 profile comprised of various ethnic founder variants resulting in two or three major retinal phenotypes.

Variants in the ABCA4 gene are associated with a spectrum of inherited retinal diseases (IRDs), most prominently with autosomal recessive (ar) Stargardt disease (STGD1) and ar cone-rod dystrophy. The clinical outcome to a large degree depends on the severity of the variants. To provide an accurate prognosis and to select patients for novel treatments, functional significance assessment of nontruncating ABCA4 variants is important. We collected all published ABCA4 variants from 3,928 retinal dystrophy cases in a Leiden Open Variation Database, and compared their frequency in 3,270 Caucasian IRD cases with 33,370 non-Finnish European control individuals. Next to the presence of 270 protein-truncating variants, 191 nontruncating variants were significantly enriched in the patient cohort. Furthermore, 30 variants were deemed benign. Assessing the homozygous occurrence of frequent variants in IRD cases based on the allele frequencies in control individuals confirmed the mild nature of the p.[Gly863Ala, Gly863del] variant and identified three additional mild variants (p.(Ala1038Val), c.5714+5GA, and p.(Arg2030Gln)). The p.(Gly1961Glu) variant was predicted to act as a mild variant in most cases. Based on these data, in silico analyses, and American College of Medical Genetics and Genomics guidelines, we provide pathogenicity classifications on a five-tier scale from benign to pathogenic for all variants in the ABCA4-LOVD database.

PURPOSE. We evaluated the pathogenicity of the G1961E mutation in the ABCA4 gene, and present the range of retinal phenotypes associated with this mutation in homozygosity in a patient cohort with ABCA4-associated phenotypes. METHODS. Patients were enrolled from the ABCA4 disease database at Columbia University or by inquiry from collaborating physicians. Only patients homozygous for the G1961E mutation were enrolled. The entire ABCA4 gene open reading frame, including all exons and flanking intronic sequences, was sequenced in all patients. Phenotype data were obtained from clinical history and examination, fundus photography, infrared imaging, fundus autofluorescence, fluorescein angiography, and spectral domain-optical coherence tomography. Additional functional data were obtained using the full-field electroretinogram, and static or kinetic perimetry. RESULTS. We evaluated 12 patients homozygous for the G1961E mutation. All patients had evidence of retinal pathology consistent with the range of phenotypes observed in ABCA4 disease. The latest age of onset was recorded at 64 years, in a patient diagnosed initially with age-related macular degeneration (AMD). Of 6 patients in whom severe structural (with/ without functional) fundus changes were detected, 5 had additional, heterozygous or homozygous, variants detected in the ABCA4 gene. CONCLUSIONS. Homozygous G1961E mutation in ABCA4 results in a range of retinal pathology. The phenotype usually is at the milder end of the disease spectrum, with severe phenotypes linked to the presence of additional ABCA4 variants. Our report also highlights that milder, late-onset Stargardt disease may be confused with AMD. (Invest Ophthalmol Vis Sci. 2012; 53:4458–4467) DOI:10.1167/iovs.11-9166

Despite significant progress in the identification of genetic loci for age-related macular degeneration (AMD), not all of the heritability has been explained. To identify variants which contribute to the remaining genetic susceptibility, we performed the largest meta-analysis of genome-wide association studies to date for advanced AMD. We imputed 6 036 699 single-nucleotide polymorphisms with the 1000 Genomes Project reference genotypes on 2594 cases and 4134 controls with follow-up replication of top signals in 5640 cases and 52 174 controls. We identified two new common susceptibility alleles, rs1999930 on 6q21-q22.3 near FRK/COL10A1 [odds ratio (OR) 0.87; P = 1.1 x 10(-8)] and rs4711751 on 6p12 near VEGFA (OR 1.15; P = 8.7 x 10(-9)). In addition to the two novel loci, 10 previously reported loci in ARMS2/HTRA1 (rs10490924), CFH (rs1061170, and rs1410996), CFB (rs641153), C3 (rs2230199), C2 (rs9332739), CFI (rs10033900), LIPC (rs10468017), TIMP3 (rs9621532) and CETP (rs3764261) were confirmed with genome-wide significant signals in this large study. Loci in the recently reported genes ABCA1 and COL8A1 were also detected with suggestive evidence of association with advanced AMD. The novel variants identified in this study suggest that angiogenesis (VEGFA) and extracellular collagen matrix (FRK/COL10A1) pathways contribute to the development of advanced AMD. Hum Mol Genet

Autosomal recessive Stargardt disease (STGD1, MIM 248200) is caused by mutations in the ABCA4 gene. Complete sequencing of the ABCA4 locus in STGD1 patients identifies two expected disease-causing alleles in ∼75% of patients and only one mutation in ∼15% of patients. Recently, many possibly pathogenic variants in deep intronic sequences of ABCA4 have been identified in the latter group. We extended our analyses of deep intronic ABCA4 variants and determined that one of these, c.4253+43G>A (rs61754045), is present in 29/1155 (2.6%) of STGD1 patients. The variant is found at statistically significantly higher frequency in patients with only one pathogenic ABCA4 allele, 23/160 (14.38%), MAF = 0.072, compared to MAF = 0.013 in all STGD1 cases and MAF = 0.006 in the matching general population (P < 1 × 10−7). The variant, which is not predicted to have any effect on splicing, is the first reported intronic “extremely hypomorphic allele” in the ABCA4 locus; that is, it is pathogenic only when in trans with a loss-of-function ABCA4 allele. It results in a distinct clinical phenotype characterized by late onset of symptoms and foveal sparing. In ∼70% of cases the variant was allelic with the c.6006-609T>A (rs575968112) variant, which was deemed nonpathogenic. Another rare deep intronic variant, c.5196+1056A>G (rs886044749), found in 5/834 (0.6%) of STGD1 cases is, conversely, a severe allele. This study determines pathogenicity for three noncoding variants in STGD1 patients of European descent accounting for ∼3% of the disease. Defining disease-associated alleles in the noncoding sequences of the ABCA4 locus can be accomplished by integrated clinical and genetic analyses.

Purpose To correlate visual acuity of patients with Leber's congenital amaurosis (LCA) and early childhood-onset retinitis pigmentosa (RP) with mutations in underlying LCA genes. Design Multicentered retrospective observational study. Participants After exclusion of 28 subjects, 169 patients with the diagnosis of LCA and 27 patients with early childhood-onset RP were included in the study because the underlying mutations in AIPL1, GUCY2D, RDH12, RPE65, CRX, CRB1, RPGRIP1, CEP290, LCA5 , and TULP1 genes could be identified in this cohort of patients. Methods We collected data on best-corrected visual acuity as recorded at the time of the patient's most recent visit to one of the participating ophthalmology departments. The median and range of visual acuities for each genetic subtype were calculated separately for the LCA and early childhood-onset RP groups. Main Outcome Measures The range and median best-corrected visual acuities for each genetic subtype and age-related mean visual acuities for each genetic subtype. Results A wide variation in visual acuity was observed in patients with LCA and RPE65, RDH12 , and CRB1 mutations, whereas AIPL1, GUCY2D, CRX , and RPGRIP1 gene mutations were associated with severely decreased visual acuities beginning within the first year of life. It was also noted that patients with either an RPE65 or CRB1 mutation have progressive visual loss with advancing age. Onset of visual symptoms after infancy was associated with a relatively better visual prognosis. Conclusions The data obtained from this study will help clinicians provide counseling on visual prognosis to patients with known mutations in LCA genes and be of value in future studies aimed at the treatment of LCA and early childhood-onset RP. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Purpose We sought to advance interpretations and quantification of short-wavelength fundus autofluorescence (SW-AF) emitted from bisretinoid lipofuscin and near-infrared autofluoresence (NIR-AF) originating from melanin. Methods Carriers of mutations in X-linked GPR143/OA1, a common form of ocular albinism; patients with confirmed mutations in ABCA4 conferring increased SW-AF; and subjects with healthy eyes were studied. SW-AF (488 nm excitation, 500-680 nm emission) and NIR-AF (excitation 787 nm, emission >830 nm) images were acquired with a confocal scanning laser ophthalmoscope. SW-AF images were analyzed for quantitative autofluoresence (qAF). Analogous methods of image acquisition and analysis were performed in albino and pigmented Abca4-/- mice and wild-type mice. Results Quantitation of SW-AF (qAF), construction of qAF color-coded maps, and examination of NIR-AF images from GPR143/OA1 carriers revealed mosaics in which patches of fundus exhibiting NIR-AF signal had qAF levels within normal limits whereas the hypopigmented areas in the NIR-AF image corresponded to foci of elevated qAF. qAF also was increased in albino versus pigmented mice. Although melanin contributes to fundus infrared reflectance, the latter appeared to be uniform in en face reflectance images of GPR143/OA1-carriers. In patients diagnosed with ABCA4-associated disease, NIR-AF increased in tandem with increased qAF originating in bisretinoid lipofuscin. Similarly in Abca4-/- mice having increased SW-AF, NIR-AF was more pronounced than in wild-type mice. Conclusions These studies corroborate RPE melanin as the major source of NIR-AF but also indicate that bisretinoid lipofuscin, when present at sufficient concentrations, contributes to the NIR-AF signal. Ocular melanin attenuates the SW-AF signal.

The death of cells in the cell layer known as the retinal pigment epithelium (RPE) leads to blindness in many diseases, including age-related macular degeneration (AMD) and various forms of retinitis pigmentosa (RP). AMD alone affects approximately 8 million Americans, and its incidence is expected to double by 2020. Hence, RPE loss accounts for a significant number of neurodegenerative diseases that severely impair activities of daily living and cause psychological depression. Cell transplantation into the human retina has the potential to restore lost vision and to provide treatment of advanced stages of retinal degeneration with significant RPE loss (1–6). Replacement of damaged RPE in AMD is currently offered in many hospitals (7–16). However, donor tissue from primary fetal RPE and neuroretinal sheets are not readily obtainable from aborted fetuses, and endogenous viruses and other pathogens may not be easily detected in primary fetal cultures. Stem cells, in contrast, may provide improved cell transplantation material for future clinical practice. Recent studies suggest that ES cell-derived RPE cells are more akin to in vivo RPE cells than human RPE cell lines in morphology, gene expression, and immunohistochemical analysis (17–19). Although some differentiation protocols have derived RPE from ES cells of rodent (4, 20) and primate (1, 6, 21) origin, no studies have reported using these differentiated ES cells in treating diseased animals of the same species. It is imperative to have results from animal disease models before applying this type of treatment to humans. Retinal pigment epithelium-specific protein 65 kDa (RPE65) is an all-trans to 11-cis isomerase (22). Thus, if RPE65 is nonfunctional or absent, then rhodopsin cannot be formed because no 11-cis-retinal is synthesized. Some inherited retinal diseases, including Leber congenital amaurosis (LCA) and RP, are caused by mutations in the gene encoding RPE65. An experimental mouse model, Rpe65tm1/Rpe65tm1 (129/Sv strain background) (23), has been developed to monitor the efficacy of RPE transplantation. We have successfully rescued this mutant phenotype by using RPE transplants (24). An apparent limitation of the Rpe65tm1/Rpe65tm1 model used in this original study was that RPE rescue persisted for only 4 months, most likely because of rejection of the RPE graft. The diseased mice were in the 129/Sv background, whereas the donor tissue was from mice of the C57BL/6J strain. Host rejection also limited other ES cell transplantation studies in the retina (25, 26). However, rejection can be overcome by using isogenic donor cells and recipient animals. More recently, a spontaneous mutant rodent model of Rpe65 LCA, the Rpe65rd12/Rpe65rd12 (rd12) mouse (C57BL/6J genetic background), has been reported (27). This mouse is of the same genetic background as our newly derived C2J ES cells, from a C57BL/6J-Tyrc−2j/J mouse. In others words, our C2J donor cells should not be rejected by a C57BL/6J host. In addition, we have genetically engineered C2J cells to express a yellow fluorescent protein (YFP) to mark the location of transplants by live imaging. The purpose of this study was to determine whether C2J ES cells will differentiate into RPE-like cells and improve retinal function in the rd12 mouse. To accomplish this, we transplanted ES cell-derived RPE-like cells into the subretinal space of postnatal day 5 (P5) rd12 mice. To determine whether any rescue effects were due to surgery or feeder cells, we grafted an additional three groups of rd12 mice with phosphate-buffered saline (PBS), mitomycin-C treated PA6 feeders, and mitomycin-C treated undifferentiated mouse ES cells. Encouragingly, the ES cell-derived RPE-like cells expressed RPE markers, and the mice transplanted with these cells showed significant responses by electroretinogram (ERG) that did not occur in the control groups.

Advanced age-related macular degeneration (AMD) is the leading cause of late onset blindness. We present results of a genome-wide association study of 979 advanced AMD cases and 1,709 controls using the Affymetrix 6.0 platform with replication in seven additional cohorts (totaling 5,789 unrelated cases and 4,234 unrelated controls). We also present a comprehensive analysis of copy-number variations and polymorphisms for AMD. Our discovery data implicated the association between AMD and a variant in the hepatic lipase gene ( LIPC ) in the high-density lipoprotein cholesterol (HDL) pathway (discovery P = 4.53e-05 for rs493258). Our LIPC association was strongest for a functional promoter variant, rs10468017, ( P = 1.34e-08), that influences LIPC expression and serum HDL levels with a protective effect of the minor T allele (HDL increasing) for advanced wet and dry AMD. The association we found with LIPC was corroborated by the Michigan/Penn/Mayo genome-wide association study; the locus near the tissue inhibitor of metalloproteinase 3 was corroborated by our replication cohort for rs9621532 with P = 3.71e-09. We observed weaker associations with other HDL loci ( ABCA1 , P = 9.73e-04; cholesterylester transfer protein, P = 1.41e-03; FADS1-3 , P = 2.69e-02). Based on a lack of consistent association between HDL increasing alleles and AMD risk, the LIPC association may not be the result of an effect on HDL levels, but it could represent a pleiotropic effect of the same functional component. Results implicate different biologic pathways than previously reported and provide new avenues for prevention and treatment of AMD.

Age-related macular degeneration (AMD) is a late onset vision disorder. Recent studies demonstrate that alterations in complement cascade genes are associated with AMD. Of the three identified complement loci, variants in complement factor H (CFH) have the highest impact as does an independent locus at 10q26. Our matched case–control study using the Age-Related Eye Disease Study (AREDS) cohort confirms and extends the associations in these loci. Subjects were genotyped for single nucleotide polymorphisms (SNPs) from CFH, complement component 2 (C2), complement component 3 (C3), complement factor B (CFB), age-related maculopathy susceptibility (ARMS2), HtrA serine peptidase 1 (HTRA1), and apolipoprotein E (APOE). Individual SNPs, and haplotypes showed risk trends consistent with those seen in other population studies for CFH, C3, C2, and CFB. SNP rs10490924 on chromosome 10 in exon 1 of the ARMS2 gene showed a highly significant association with an odds ratio (OR) of 3.2 (95% CI 2.4–4.2) for the risk allele and rs11200638 located in the proximal promoter region of HTRA1 showed a higher significant association with an OR of 3.4 (95% CI 2.5–4.6) with our AMD cases. We found that APOE haplotypes were not significantly associated with disease status. Adjustments for other risk factors did not significantly alter the observed associations. This study validates the complement pathway's involvement in AMD and suggests that allelic variants in complement genes have a direct role in disease. These results also support previous findings that variants in the region of 10q26 exert an independent risk for AMD.

Leber congenital amaurosis (LCA) is a group of severe autosomal recessive retinal dystrophies defined by the onset of blindness at birth and absent electroretinographic signals. LCA is the most common cause of infant blindness in schools for the blind with approximately 200,000 humans affected worldwide. In total, 14 genes are associated with LCA and mutations in these retinal genes account for approximately 60% of patients. LCA genes encode proteins that participate in a wide variety of cycles, ranging from photoreceptor development to vitamin A cycling. Genetic heterogeneity and a variety of disease mechanisms provide for many genotype–phenotype correlations. Genetic studies suggest that Leber congenital amaurosis may be a developmental disorder and successful photoreceptor and visual rescue have been achieved in mice, dogs and recently man.

To describe a series of patients with Stargardt disease (STGD1) exhibiting a phenotype usually associated with hydroxychloroquine (HCQ) retinopathy on spectral domain-optical coherence tomography (SD-OCT). Observational case series from Columbia University Medical Center involving eight patients with genetically-confirmed STGD1. Patients selected for the study presented no history of HCQ use. Horizontal macular SD-OCT scans and accompanying 488-nm autofluorescence (AF) images, color fundus photographs, and full-field electroretinograms were analyzed. All study patients exhibited an abrupt thinning of the parafoveal region or disruption of the outer retinal layers on SD-OCT resembling the transient HCQ retinopathy phenotype. Funduscopy and AF imaging revealed variations of bull’s eye maculopathy (BEM). Five patients exhibited local fleck-like deposits around the lesion. Genetic screening confirmed two disease-causing ABCA4 mutations in five patients and one mutation in three patients. A transient SD-OCT phenotype ascribed to patients with HCQ retinopathy is associated with an early subtype of STGD1. This finding may also present with HCQ retinopathy-like BEM lesions on AF imaging and funduscopy. A possible phenotypic overlap is unsurprising, given certain shared mechanistic disease processes between the two conditions. A thorough work-up, including screening of genes that are causal in retinal dystrophies associated with foveal sparing, may prevent misdiagnosis of more ambiguous cases.

Recessive Stargardt disease (STGD1), caused by mutations in the gene ABCA4,1 follows an autosomal recessive mode of inheritance and usually manifests in the first two decades of life,2 although late-onset forms of STGD1 also exist.3 Typical phenotypic features of STGD1 include intensely fluorescent foci (flecks) that emerge with disease progression, mottling of the retinal pigment epithelium (RPE), and central atrophy.4,5 These fundus changes can be confined to the macula or extend beyond the vascular arcades. Another fundus feature that is considered pathognomonic for ABCA4-related disease is relative sparing of the peripapillary area from flecks and atrophy.6,7 However, peripapillary sparing does not necessarily persist with ABCA4-related disease progression.8 Foveal atrophy is common in STGD1 patients, even at young ages, although in some patients the fovea is spared.9 On fluorescein angiography, STGD1 patients also often, but not always, exhibit a “dark choroid.”10 Despite the frequency with which STGD1 can be defined by these features, the phenotype is not necessarily exclusive to STGD1. For instance, peripapillary sparing can also be present in cases of pattern dystrophy (PD) without ABCA4 mutations,11 and both STGD1 and PD can present with pigmentary changes identified as flecks and mottling.12 Pattern dystrophy refers to a genetically heterogeneous group of retinal disorders, with mutations in PRPH2/RDS being the most common cause.4 Pattern dystrophy is usually inherited in an autosomal dominant manner and usually manifests in midlife with mild-to-moderate vision loss.13,14 In PD with an absence of ABCA4 mutations, foveal atrophy is generally found only in late stages of the disease.13 Histopathological studies, spectrophotometric analysis, and studies in mouse models have demonstrated over many years that the formation of RPE cell lipofuscin is augmented and pathogenic in ABCA4-associated disease.15–18 Retinal pigment epithelium lipofuscin, a mixture of fluorophores with spectral features that reflect its bisretinoid constituents,19 is the primary source of fundus AF, with a minor contribution from Bruch's membrane.20 We recently demonstrated that the increase in RPE lipofuscin in STGD1 can be measured indirectly by quantifying fundus autofluorescence intensities in images acquired by confocal scanning laser ophthalmoscope (cSLO).21,22 Quantitative fundus autofluorescence (qAF) was also shown to be a valuable tool for distinguishing ABCA4-related from non-ABCA4-related bull's-eye maculopathy (BEM).23 Here we present a patient cohort that, because they presented with clinical features of STGD1, were referred to our medical center for ABCA4 genetic screening. In all patients the clinical evaluation included qAF imaging and analysis. We report that some of these patients were ultimately found to carry mutations in PRPH2/RDS. The inheritance pattern of PD can often not be readily discerned because incomplete penetrance24 and variable expression can mask dominant inheritance. Whether PRPH2/RDS patients exhibit increased lipofuscin levels has been a matter of debate.4,25 Thus our objective was to consider whether qAF can assist in distinguishing ABCA4-related disease from disease caused by mutations in PRPH2/RDS and other unknown genes. Given the phenotypic overlap between some cases of ABCA4- and PRPH2/RDS-associated disease,4,5 we also assessed AF and spectral-domain optical coherence tomography (SD-OCT) images qualitatively to attempt to identify characteristic fundus features that may aid in the differentiation of these diseases. PRPH2/RDS-associated PD is generally considered to have a better prognosis than ABCA4-associated disease; thus it is important to differentiate the two conditions clinically.

BEST1 (VMD2) is a gene located on the long arm of chromosome 11 (11q12.3) that encodes for the 585 amino acid transmembrane protein bestrophin 1, located on the basolateral aspect of retinal pigment epithelial (RPE) cells.1 The exact function of bestrophin 1 is still not unequivocally characterized, but it is linked to transepithelial chloride flow possibly by controlling Ca2+ channels in the RPE.1–3 Mutations in BEST1 therefore affect RPE metabolism, and by consequence outer retinal function with which the RPE is intimately associated. Over 200 mutations in BEST1 have been identified and published.1,3,4 Mutations are associated with Best vitelliform macular dystrophy (VMD, MIM 153700), adult-onset vitelliform macular dystrophy (MIM 608161), retinitis pigmentosa 50 (RP50, MIM 613194), and autosomal dominant vitreoretinochoroidopathy (MIM 193220). These diseases are all caused by autosomal dominant mutations. Recently, a phenotype caused by autosomal recessive mutations in BEST1 was described: autosomal recessive bestrophinopathy (ARB, OMIM 611809). Autosomal recessive bestrophinopathy is a rare ocular disease. It was defined by Burgess et al1 in 2008, although the same condition with compound heterozygous mutations in VMD2 had been described 2 years earlier.5 It results from biallelic mutations in BEST1 and is characterized by a multifocal vitelliform dystrophy with subretinal fluid. An association with hypermetropia and angle closure has been described.1 Herein, we review the clinical features and mutation analysis of four families with ARB.

Background: Methylmalonic aciduria and homocystinuria type C (cblC), a disorder of vitamin B12 (cobalamin) metabolism caused by mutations in the MMACHC gene, presents with many systemic symptoms, including neurological, cognitive, psychiatric, and thromboembolic events. Retinal phenotypes, including maculopathy, pigmentary retinopathy, and optic atrophy are common in early onset form of the disease but are rare in adult onset forms. Materials and Methods: An adult Hispanic female presented with decreased central vision, bilateral pericentral ring scotomas and bull’s eye-appearing macular lesions at 28 years of age. Her medical history was otherwise unremarkable except for iron deficiency anemia and both urinary tract and kidney infections. Screening of the ABCA4 gene, mutations in which frequently cause bull’s eye maculopathy, was negative. Subsequently, analysis with whole exome sequencing was performed. Results: Whole exome sequencing discovered compound heterozygous mutations in MMACHC, c.G482A:p.Arg161Gln and c.270_271insA:p.Arg91Lysfs*14, which segregated with the disease in the family. The genetic diagnosis was confirmed by biochemical laboratory testing, showing highly elevated urine methylmalonic acid/creatinine and homocysteine levels, and suggesting disease management with hydroxycobalamin injections and carnitine supplementation. Conclusions: In summary, a unique case of an adult patient with bull’s eye macular lesions and no clinically relevant systemic symptoms was diagnosed with cblC by genetic screening and follow-up biochemical laboratory tests.

The ATP-binding cassette (ABC) transporter gene, ABCA4 (ABCR), was characterized in 1997 as the causal gene for autosomal recessive Stargardt disease (STGD1). Shortly thereafter several other phenotypes were associated with mutations in ABCA4, which now have collectively emerged as the most frequent cause of retinal degeneration phenotypes of Mendelian inheritance. ABCA4 functions as an important transporter (or "flippase") of vitamin A derivatives in the visual cycle. Several ways to alleviate the effects of the defective ABCA4 protein, which cause accumulation of 11-c/s and all-trans-retinal in photoreceptors and lipofuscin in the retinal pigment epithelium, have been proposed. Although ABCA4 has proven to be a difficult research target, substantial progress through genetic, functional, and translational studies has allowed major advances in therapeutic applications for ABCA4-associated pathology, which should be available to patients in the (near) future. Here, we summarize the status of the gene therapy-based treatment options of ABCA4-associated diseases. © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

Age-related macular degeneration (AMD) is the most common form of irreversible blindness in developed countries. Variants in the factor H gene (CFH, also known as HF1), which encodes a major inhibitor of the alternative complement pathway, are associated with the risk for developing AMD. Here we test the hypothesis that variation in genes encoding other regulatory proteins of the same pathway is associated with AMD. We screened factor B (BF) and complement component 2 (C2) genes, located in the major histocompatibility complex class III region, for genetic variation in two independent cohorts comprising approximately 900 individuals with AMD and approximately 400 matched controls. Haplotype analyses identify a statistically significant common risk haplotype (H1) and two protective haplotypes. The L9H variant of BF and the E318D variant of C2 (H10), as well as a variant in intron 10 of C2 and the R32Q variant of BF (H7), confer a significantly reduced risk of AMD (odds ratio = 0.45 and 0.36, respectively). Combined analysis of the C2 and BF haplotypes and CFH variants shows that variation in the two loci can predict the clinical outcome in 74% of the affected individuals and 56% of the controls. These data expand and refine our understanding of the genetic risk for AMD.

Contains fulltext : 50306.pdf (Publisher’s version ) (Closed access) PURPOSE: To test human CRB1 heterozygotes for possible clinical or functional retinal changes and to evaluate whether a patient with Leber congenital amaurosis (LCA) with CRB1 mutations not consistent with previously described CRB1 phenotypes carried a modifier allele in another LCA gene. METHODS: Seven unrelated heterozygous carriers of CRB1 mutations underwent phenotyping by full eye examinations (indirect ophthalmoscopy and slit lamp biomicroscopy) and functional testing (standard full-field electroretinography [ERG] and multifocal ERG). For genotyping of the LCA patients and their parents, denaturing high-performance liquid chromatography (dHPLC) analyses were performed, followed by sequence analysis of CRB1, followed by sequence analysis of the AIPL1 and CRX genes to identify a putative modifier effect in a patient with an atypical CRB1 phenotype. RESULTS: Reduced full-field ERG b-wave amplitudes were observed with scotopic -2 dB flash (140 microV; P < 0.05), normal full-field cone ERGs, and significant regional retinal dysfunction on mfERG in five of seven carriers of CRB1 mutations. A known AIPL1 mutation (p. R302L) was identified as a potential modifier allele in a patient with LCA carrying two CRB1 mutations and with a prominent maculopathy. CONCLUSIONS: In human heterozygotes of CRB1 mutations (parents of offspring with LCA), distinctive regional retinal dysfunctions were found by multifocal ERG measurements that were consistent with the focal histologic abnormalities reported for the two CRB1 knockout mice models. This phenotypic finding may identify CRB1 carriers and point to the causal gene defect in affected LCA offspring, significantly facilitating the molecular diagnostic process. Evidence suggests a modifier allele in AIPL1 in a patient with LCA with prominent atrophic macular lesions and homozygous defects in CRB1.

The accumulation of the lipofuscin fluorophores in retinal pigment epithelial (RPE) cells leads to the blinding degeneration characteristic of Stargardt disease and related forms of macular degeneration. RPE lipofuscin, including the fluorophore A2E, forms in large part as a byproduct of the visual cycle. Inhibiting visual cycle function with small molecules is required to prevent the formation of the retinotoxic lipofuscins. This in turn requires identification of rate-limiting steps in the operation of the visual cycle. Specific, non-retinoid isoprenoid compounds are described here, and shown through in both in vitro and in vivo experiments, to serve as antagonists of RPE65, a protein that is essential for the operation of the visual cycle. These RPE65 antagonists block regeneration of 11-cis-retinal, the chromophore of rhodopsin, thereby demonstrating that RPE65 is at least partly rate-limiting in the visual cycle. Furthermore, chronic treatment of a mouse model of Stargardt disease with the RPE65 antagonists abolishes the formation of A2E. Thus, RPE65 is also on the rate-limiting pathway to A2E formation. These nontoxic isoprenoid RPE65 antagonists are candidates for the treatment of forms of macular degeneration wherein lipofuscin accumulation is an important risk factor. These antagonists will also be used to probe the molecular function of RPE65 in vision.

Several lines of investigation suggest that the nondegradable fluorophores that accumulate as lipofuscin in retinal pigment epithelium (RPE) cells contribute to the etiology of macular degeneration. Despite evidence that much of this fluorescent material may originate as inadvertent products of the retinoid cycle, the enzymatic pathway by which the 11- cis -retinal chromophore of rhodopsin is generated, the only fluorophores of the RPE to be characterized as yet have been A2E and its isomers. Here, we report the isolation and structural characterization of an additional RPE lipofuscin fluorophore that originates as a condensation product of two molecules of all-trans -retinal (ATR) dimer and forms a protonated Schiff base conjugate with phosphatidylethanolamine (PE), the latter conjugate (ATR dimer-PE) having UV-visible absorbance maxima at 285 and 506 nm. ATR dimer was found to form natively in bleached rod outer segments in vitro and when rod outer segments were incubated with ATR. HPLC analysis of eyecups that included RPE and isolated neural retina from Abcr -/- mice and RPE isolated from human donor eyes revealed the presence of a pigment with the same UV-visible absorbance and retention time as synthetic ATR dimer-PE conjugate. Evidence that ATR dimer undergoes a photooxidation process involving the addition of oxygens at double bonds as well as an aromatic demethylation also may indicate a role for this molecule, or its derivatives, in the photoreactivity of RPE lipofuscin.

Autosomal recessive Stargardt disease (STGD) has been associated with substantial genetic and phenotypic heterogeneity. By systematic clinical analyses of STGD patients with complete genetic data (i.e. identified mutations on both alleles of the ABCA4 gene), we set out to determine phenotypic subtypes and to correlate these with specific ABCA4 alleles. Twenty-eight patients from 18 families with STGD/fundus flavimaculatus were investigated. All patients were submitted to complete ophthalmologic examination, electrophysiology, fluorescein angiography and ABCA4 gene chip analysis. Two main clinical phenotypes were observed among the examined patients. The severe phenotype was characterized by the onset of the disease

Leber congenital amaurosis (LCA; estimated prevalence 1 : 50,000-100,000) is an early-onset inherited cause of childhood blindness characterized by a severe retinal dystrophy immediately after birth. Variants in at least six genes, AIPL1, CRB1, CRX, GUCY2D, RPE65, and RPGRIP1, have been associated with a diagnosis consistent with LCA or early-onset retinitis pigmentosa and together account for less than 50% of all LCA cases. Genetically heterogeneous inheritance has complicated the molecular analysis of LCA cases, especially sporadic ones where conventional methods are of limited value. Until recently, the management of patients with LCA relied mainly on clinical examination, electrophysiology, and other ancillary tests. Genotyping, i.e., determining the exact genetic defect causing LCA in each specific case, was not routinely performed since the comprehensive screening of six genes by SSCP and/or direct sequencing is relatively inefficient and cost-prohibitive. Patients, therefore, were often left with no specific information on their disease status. Recent advances in genotyping technologies have allowed the introduction of comprehensive and affordable screening procedures to determine causal genetic variation, resulting in precise molecular diagnosis, more accurate visual prognosis, and suggestions towards treatment options.