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PURPOSE: To describe a cohort of patients with Stargardt disease who show a foveal-sparing phenotype. DESIGN: Retrospective case series. METHODS: The foveal-sparing phenotype was defined as foveal preservation on autofluorescence imaging, despite a retinopathy otherwise consistent with Stargardt disease. Forty such individuals were ascertained and a full ophthalmic examination was undertaken. Following mutation screening of ABCA4, the molecular findings were compared with those of patients with Stargardt disease but no foveal sparing. RESULTS: The median age of onset and age at examination of 40 patients with the foveal-sparing phenotype were 43.5 and 46.5 years. The median logMAR visual acuity was 0.18. Twenty-two patients (22/40, 55%) had patchy parafoveal atrophy and flecks; 8 (20%) had numerous flecks at the posterior pole without atrophy; 7 (17.5%) had mottled retinal pigment epithelial changes; 2 (5%) had multiple atrophic lesions, extending beyond the arcades; and 1 (2.5%) had a bull's-eye appearance. The median central foveal thickness assessed with spectraldomain optical coherence tomographic images was 183.0 mm (n [ 33), with outer retinal tubulation observed in 15 (45%). Twenty-two of 33 subjects (67%) had electrophysiological evidence of macular dysfunction without generalized retinal dysfunction. Disease-causing variants were found in 31 patients (31/ 40, 78%). There was a higher prevalence of the variant p.Arg2030Gln in the cohort with foveal sparing compared to the group with foveal atrophy (6.45% vs 1.07%). CONCLUSIONS: The distinct clinical and molecular characteristics of patients with the foveal-sparing phenotype are described. The presence of 2 distinct phenotypes of Stargardt disease (foveal sparing and foveal atrophy) [ABSTRACT FROM AUTHOR]

Retinitis pigmentosa (RP) is a genetically heterogeneous retinal degeneration characterized by photoreceptor death, which results in visual failure. Here, we used a combination of homozygosity mapping and exome sequencing to identify mutations in ARL2BP, which encodes an effector protein of the small GTPases ARL2 and ARL3, as causative for autosomal-recessive RP (RP66). In a family affected by RP and situs inversus, a homozygous, splice-acceptor mutation, c.101−1G>C, which alters pre-mRNA splicing of ARLBP2 in blood RNA, was identified. In another family, a homozygous c.134T>G (p.Met45Arg) mutation was identified. In the mouse retina, ARL2BP localized to the basal body and cilium-associated centriole of photoreceptors and the periciliary extension of the inner segment. Depletion of ARL2BP caused cilia shortening. Moreover, depletion of ARL2, but not ARL3, caused displacement of ARL2BP from the basal body, suggesting that ARL2 is vital for recruiting or anchoring ARL2BP at the base of the cilium. This hypothesis is supported by the finding that the p.Met45Arg amino acid substitution reduced binding to ARL2 and caused the loss of ARL2BP localization at the basal body in ciliated nasal epithelial cells. These data demonstrate a role for ARL2BP and ARL2 in primary cilia function and that this role is essential for normal photoreceptor maintenance and function. [Copyright &y& Elsevier]

Abstract: A diagnosis of choroideraemia (CHM) can be made clinically, based on the fundus examination and a family history consistent with X-linked inheritance. Molecular genetic testing offers a means of confirming the clinical diagnosis, establishing carrier status and allows presymptomatic diagnosis for families who wish to pursue these options. The aim of this study was to examine the uptake and assess the results from a diagnostic molecular genetics service for CHM. We have carried out a comprehensive audit of all molecular genetic results of UK NHS patients and families referred to the North West Regional Molecular Genetics Laboratory in Manchester, UK over a 55 month period. 110 people were referred to this service for testing including diagnostic, carrier and predictive requests. Putative pathogenic mutations were identified in 65/83 (78%) of male index cases. The identification of a familial pathogenic change enabled carrier testing in 16 asymptomatic females and predictive testing in 3 males. Case examples illustrate the range of cases referred for testing and also reflect the need for genetic counselling that results from offering a molecular diagnostic service such as this. Clinical molecular testing for CHM is available clinically and can be used to support the clinical diagnosis and management of patients with choroideraemia as well as their families. Case studies demonstrate the need to provide genetic testing to families and the potential clinical utility of testing. [Copyright &y& Elsevier]

Purpose: Significant phenotypic overlap exists between ocular albinism and SLC38A8 related foveal hypoplasia (FH) which hinders differential diagnosis. To facilitate molecular testing, we catalogued the spectrum of known pathogenic variants in SLC38A8 responsible for FH. Methods: The UK 100 000 genomes (100KG) datasets were analysed to detect pathogenic SLC38A8 variants compatible with recessive inheritance in cases with phenotypes reminiscent of FH. Published literature was accessed to capture deleterious variants reported in FH affected families. Additional variants identified locally were incorporated for bioinformatic analysis. Variant interpretation included in‐silico pathogenicity assessment, population data and protein modelling. Results: In total, 41 pathogenic variants in SLC38A8 have been identified in 51 FH families; 17 missense, 4 splice site, 2 in‐frame deletions, 6 frameshift, 6 nonsense, 4 large deletions, a multiple exon inversion and a whole gene deletion. Nonsense variants are evenly distributed throughout the gene and protein, while missense variants are more likely to reside in transmembrane domains. 38 SLC38A8 variants were reported in the literature and we have identified 3 novel and 2 known variants in 4 families derived from the 100KG datasets and our local cohort. In one patient, a novel g.84049578_84060679inv (GRCh37) was detected in a homozygous state. Another harboured novel variant c.922_923insTG, p.(Thr308Metfs*14) and c.922A>G, p.(Thr308Ala). Other homozygous variants include c.848A>C, p.(Asp283Ala) and novel variant c.77C>T, p.(Ser26leu). Protein modelling of SLC38A8 predicted a destabilising effect by both p.(Ser26leu) and p.(Thr308Ala). Haplotype analysis of Pakistani, Bangladeshi and Indian patients harbouring c.264C>G, p.(Tyr88*) suggest a South Asian founder effect. Conclusions: We reviewed and extended the spectrum of SLC38A8 variants causative for FH. The presence of multiple nonsense variants and in‐silico modelling of missense variants suggests a complete loss of function as the likely disease mechanism. [ABSTRACT FROM AUTHOR]

Purpose: To compare the clinical phenotype and detailed electroretinographic parameters in X-linked retinoschisis (XLRS). Design: Retrospective, comparative study. Participants: Fifty-seven patients (aged 1-67 years) with molecularly confirmed XLRS were clinically ascertained. Methods: Pattern eiectroretinography (PERG) and full-field electroretinography (ERG), incorporating inter-national standard recordings, were performed in 44 cases. Thirteen patients, mostly pediatric, were tested using a simplified ERG protocol. On-Off and S-cone ERGs were performed in most adults. Fundus autofluorescence (FAF) imaging and optical coherence tomography (OCT) were available in 17 and 21 cases, respectively. Main Outcome Measures: The clinical and electrophysiologic data associated with different types of mutation in the RS1 gene. Results: Forty-three patients had missense changes (group A), and 14 patients had nonsense, splice-site, or frame-shifting mutations in the RS1 gene (group B). The mean best-corrected visual acuity was better in group A than in group B (0.34 and 0.21, respectively). Fundus examination revealed foveal schisis in approximately half of both groups. The bright-flash dark-adapted (DA) ERG (11.0 candela.sec.m-2) waveform was electronegative in 62% of group A eyes and 100% of group B eyes. The photopic 30-Hz flicker ERG was delayed in all group B eyes and all except 6 group A eyes. On-Off ERG b-waves were subnormal in 39% of group A and 89% of group B eyes; d-waves were delayed in 14 eyes (group A = 10, group B = 4). S-cone ERGs were abnormal in 50% of both groups. The PERG was abnormal in 88% of group A and 100% of group B eyes. A spoke-wheel pattern of high and low intensity was the most common FAF abnormality observed. The OCT showed intraretinai schitic cavities in the majority of eyes. Conclusions: There is profound phenotypic variability in patients with XLRS. Most patients have DA bright-flash ERGs with a low b:a ratio in keeping with inner retinal dysfunction. Generalized cone system dysfunction is common and associated with an abnormal On-response and less frequent additional Off-response involvement. Nonsense, splice-site, or frame-shifting mutations in RS1 consistently caused electronegative bright-flash ERG, delayed flicker response, and abnormal PERG; missense mutations result in a wider range of ERG abnormalities. [ABSTRACT FROM AUTHOR]

Background. Previous studies have focused on the treatment received by rural cancer patients and have not examined their diagnostic pathways as reasons for poorer outcomes in rural Australia. Objectives. To compare and explore symptom appraisal and help-seeking behaviour in patients with breast, lung, prostate or colorectal cancer from rural Western Australia (WA). Methods. A mixed-methods study of people recently diagnosed with breast, lung, prostate or colorectal cancer from rural WA. The time from first symptom to diagnosis (i.e. total diagnostic interval, TDI) was calculated from interviews and medical records. Results. Sixty-six participants were recruited (24 breast, 20 colorectal, 14 prostate and 8 lung cancer patients). There was a highly significant difference in time from symptom onset to seeking help between cancers (P = 0.006). Geometric mean symptom appraisal for colorectal cancer was significantly longer than that for breast and lung cancers [geometric mean differences: 2.58 (95% confidence interval, CI: 0.64–4.53), P = 0.01; 3.97 (1.63–6.30), P = 0.001, respectively]. There was a significant overall difference in arithmetic mean TDI (P = 0.046); breast cancer TDI was significantly shorter than colorectal or prostate cancer TDI [mean difference : 266.3 days (95% CI: 45.9–486.8), P = 0.019; 277.0 days, (32.1–521.9), P = 0.027, respectively]. These differences were explained by the nature and personal interpretation of symptoms, perceived as well as real problems of access to health care, optimism, stoicism, machismo, fear, embarrassment and competing demands. Conclusions. Longer symptom appraisal was observed for colorectal cancer. Participants defined core characteristics of rural Australians as optimism, stoicism and machismo. These features, as well as access to health care, contribute to later presentation of cancer. [ABSTRACT FROM AUTHOR]

PURPOSE: To investigate the clinical and electrophysiologic natural history of Stargardt disease and correlate with the genotype. DESIGN: Cohort study of 59 patients. METHODS: Clinical history, examination, and electrophysiologic assessment were undertaken in a longitudinal survey. Patients were classified into 3 groups based on electrophysiologic findings, as previously published: Group 1 had dysfunction confined to the macula; Group 2 had macular and generalized cone system dysfunction; and Group 3 had macular and both generalized cone and rod system dysfunction. At baseline, there were 27 patients in Group 1, 17 in Group 2, and 15 in Group 3. Amplitude reduction of>50% in the relevant electroretinogram (ERG) component or a peak time shift of >3 ms for the 30 Hz flicker ERG or bright flash a-wave was considered clinically significant ERG deterioration. Molecular screening of ABCA4 was undertaken. RESULTS: The mean age at baseline was 31.7 years, with the mean follow-up interval being 10.5 years. Atotal of 22% of patients from Group 1 showed ERG group transition during follow-up, with 11% progressing to Group 2 and 11% to Group 3. Forty-seven percent of patients in Group 2 progressed to Group 3. There was clinically significant ERG deterioration in 54% of all subjects: 22% of Group 1, 65% of Group 2, and 100% of Group 3. At least 1 disease-causing ABCA4 variant was identified in 47 patients. CONCLUSIONS: All patients with initial rod ERG involvement demonstrated clinically significant electrophysiologic deterioration; only 20% of patients with normal full-field ERGs at baseline showed clinically significant progression. Such data assist counseling by providing more accurate prognostic information and are also highly relevant in the design, patient selection, and monitoring of potential therapeutic interventions. [ABSTRACT FROM AUTHOR]

. Purpose: To describe the ocular and electrophysiological phenotype of four patients with late-onset retinal degeneration (LORD). Methods: Clinical examination, fundus and anterior segment photography, fundus autofluorescence imaging and spectral domain optical coherence tomography (SD-OCT) were performed. Three patients underwent pattern and full-field electroretinography (ERG). Patient DNA was screened for the c.686C>G, p.Ser163Arg mutation in C1QTNF5. Results: All affected individuals had a family history suggestive of autosomal dominant inheritance with full penetrance. Molecular analysis identified a heterozygous c.686C>G, p.Ser163Arg mutation in C1QTNF5 in DNA from all four affected probands. All four patients presented in their 50s with nyctalopia and developed central visual loss in their 60s. Peripupillary iris atrophy and long anterior zonular insertions were present in three of four patients. Dilated fundus examination revealed scalloped areas of retinal pigment epithelium (RPE) atrophy in the mid-periphery and widespread atrophy in the posterior pole. Full-field ERGs were consistent with rod-cone dystrophy with pattern ERG evidence of severe macular involvement. SD-OCT revealed widespread loss of the photoreceptors with absence of the inner/outer segment junction line and concurrent thinning of the outer nuclear layer. Diffuse choroidal thinning, mainly affecting the inner choroid with loss of the choriocapillaris, was observed. Conclusion: C1QTNF5 retinopathy is an autosomal dominant LORD resulting in a complex ocular phenotype involving the RPE and ciliary epithelium. SD-OCT findings revealed widespread photoreceptor loss and diffuse choroidal thinning. [ABSTRACT FROM AUTHOR]

Background Pseudoxanthoma elasticum is an inherited disorder that is associated with accumulation of pathologic elastic fibers in the skin, vascular walls and Bruch's membrane in the eye. Choroidal neovascularization is one of the most common causes of acute vision loss in these patients. We report an atypical case of suspected choroidal neovascularization associated with pseudoxanthoma elasticum. Case presentation A 47-year-old Caucasian woman with pseudoxanthoma elasticum and angioid streaks was referred because of decreased and distorted vision in her right eye of one week's duration. Visual acuity was 6/12 in the right eye and 6/6 in the left eye. Fundus examination revealed angioid streaks and white intraretinal macular deposits bilaterally. Fluorescein angiography did not reveal any obvious leakage in the right eye while optical coherence tomography revealed subretinal fluid associated with an adjacent intraretinal hyperreflective structure. Autofluoresence imaging showed focal areas of increased autofluorescence corresponding to the deposits in both eyes. Over the following year the patient underwent five intravitreal injections of bevacizumab (Genentech/Roche,US) in the right eye, which resulted in visual acuity improving to 6/9 with regression of the hyperreflective structrure and complete resolution of subretinal fluid. Conclusions Traditionally, fluorescein angiography is effective in the detection of choroidal neovascularization in patients with pseudoxanthoma elasticum. In our case, optical coherence tomography revealed subretinal fluid and an adjacent hyperreflective structure while fluorescein angiography did not reveal any obvious leakage. The sole presence of subretinal fluid does not necessarily imply the presence of choroidal neovascularization and certainly retinal pigment epithelium dysfunction could also explain subretinal fluid in these patients. However, the complete absorption of the fluid and the disappearance of the previously evident hyperreflective structure following treatment, led us to suspect choroidal neovascularization as the primary cause of the above findings. The poor natural course of choroidal neovascularization in these patients increases the importance of early detection and should result in the adaptation of a low-threshold strategy concerning the initiation of treatment. [ABSTRACT FROM AUTHOR]

PURPOSE: To assess whether laser treatment to the retinal pigment epithelium anterior to drusen in eyes of patients with EFEMP1-related maculopathy affects visual acuity, deposit volume, and retinal sensitivity. DESIGN: Prospective, interventional case series. METHODS: In 11 patients with autosomal dominant drusen and confirmed disease-causing EFEMP1 mutation, the worse-seeing eye was treated with Argon green laser (10 to 15 laser spots; 200-mm spot size, 0.1-second duration, 80 to 120 mW). Patients were examined before treatment as well as 1, 3, 6, and 12 months after the procedure. Clinical assessment included visual acuity, fundus-controlled perimetry, spectral-domain optical coherence tomography, and autofluorescence imaging. Custom-made software allowed for coregistration of fundus-controlled perimetry and spectral-domain optical coherence tomography data sets. The main outcome measures were change in visual acuity, retinal sensitivity, and drusen volume. RESULTS: The untreated eyes lost an average of 0.8 letters, whereas the treated eyes gained an average of 4.9 letters. For fundus-controlled perimetry, locusby- locus differences in sensitivity were calculated between pretreatment and posttreatment assessments; subsequently, the overall difference in the treated and untreated eye was compared. Five patients showed significant improvement in retinal sensitivity, 5 patients showed no change, and 1 patient showed significant deterioration. An increase in mean drusen thickness was observed in the untreated eyes, but not in the treated eyes (P[.0322). The thickness of the drusen correlated with retinal sensitivity (r[L0.49; P<.0001). Safety was demonstrated and no adverse events were observed. CONCLUSIONS: Low-energy laser treatment is safe and may be effective in the treatment of autosomal dominant drusen. Further evaluation with long-term assessment is required to confirm the benefits. [ABSTRACT FROM AUTHOR]

. Purpose: To describe the clinical phenotype and the molecular pathology in a group of patients with congenital stationary night blindness due to mutations in GRM6, a gene encoding the ON bipolar metabotropic glutamate receptor 6 (mGluR6). Methods: Nine patients from seven families (age range, 7-75; median, 10 years) with a clinical diagnosis of autosomal recessive complete congenital stationary night blindness were ascertained. Clinical examination, imaging and electrophysiological assessment were performed. The coding region and intron-exon boundaries of GRM6 were sequenced. Results: The median visual acuity for the cohort was 0.2 logMAR (range 0-3). Most patients had myopic astigmatism with the median spherical equivalent being −5.375 dioptres (−0.125 to −18.75). Fundoscopy was within normal limits in 15 eyes; there was severe myopic maculopathy in three eyes. Other secondary complications included face turn because of nystagmus and strabismic amblyopia. All patients had electronegative dark-adapted bright white flash electroretinograms (ERGs) consistent with dysfunction occurring postphototransduction. In the two oldest subjects (aged 75 and 58 years), there was additional photoreceptor dysfunction in keeping with myopic degeneration. ON-OFF ERGs showed generalized cone ON bipolar system dysfunction in all five patients tested. Pattern ERG P50 was normal ( Ν = 1), subnormal ( N = 2) or undetectable ( N = 2). Nine mutations in GRM6 were detected in all seven families; six of these changes were novel. Conclusions: The phenotype associated with GRM6 mutation is variable in terms of presentation, refractive error, visual acuity and macular function. ERGs are electronegative and suggest ON-pathway dysfunction. [ABSTRACT FROM AUTHOR]

Aim To describe the clinical features of a case series of patients with unilateral vitelliform maculopathy and the results of screening BEST1 and PRPH2 for diseasecausing mutations. Design/Methods This was a retrospective case series study of six patients ascertained over a 2-year period. Ophthalmological examination, fundus photography, autofluorescence imaging, optical coherence tomography and detailed electrophysiological assessment were undertaken. Blood samples were taken for DNA extraction and mutation screening of BEST1 and PRPH2 was performed. Results Six patients (3 men and 3 women) with unilateral vitelliform maculopathy were identified, ranging in age from 30 to 68 years. Vision in the affected eye ranged from 20/10 to 20/100. There was no clinical, retinal imaging or electrophysiological evidence of fellow eye involvement. Direct sequencing of BEST1 and PRPH2 did not reveal any disease-causing variants. Conclusions A case series of patients is reported with an unusual unilateral vitelliform phenotype, often associated with good visual function. The patients do not have the typical characteristics associated with agerelated maculopathy or any inherited macular disorders, such as Best vitelliform macular dystrophy. Molecular screening of the candidate genes BEST1 and PRPH2 revealed no mutations. [ABSTRACT FROM AUTHOR]

Purpose: To describe phenotypic variability and to report novel mutational data in patients with gyrate atrophy. Design: Retrospective case series. Participants: Seven unrelated patients (10 to 52 years of age) with clinical and biochemical evidence of gyrate atrophy. Methods: Detailed ophthalmologic examination, fundus photography, fundus autofluorescence (FAF) imaging, spectral-domain optical coherence tomography, and microperimetry testing were performed. The coding region and intron–exon boundaries of ornithine aminotransferase (OAT) were analyzed. OAT mRNA was isolated from peripheral blood leucocytes of 1 patient and analyzed. Main Outcome Measures: OAT mutation status and resultant clinical, structural, and functional characteristics. Results: Funduscopy revealed circular areas of chorioretinal atrophy, and FAF imaging showed sharply demarcated areas of increased or preserved signal in all 7 patients. Spectral-domain optical coherence tomography revealed multiple intraretinal cystic spaces and hyperreflective deposit in the ganglion cell layer of all study subjects. Round tubular, rosette-like structures located in the outer nuclear layer of the retinae of the 4 older patients were observed (termed outer retinal tubulation). Thickening was evident in the foveolae of younger patients, despite the posterior pole appearing relatively preserved. Macular function, assessed by microperimetry, was preserved over areas of normal or increased autofluorescence. However, sensitivity was reduced even in structurally intact parts of the retina. The molecular pathologic features were determined in all study subjects: 9 mutations, 4 novel, were detected in the OAT gene. OAT mRNA was isolated from blood leukocytes, and monoallelic expression of a mutated allele was demonstrated in 1 patient. Conclusions: Fundus autofluorescence imaging can reveal the extent of neurosensory dysfunction in gyrate atrophy patients. Macular edema is a uniform finding; the fovea is relatively thick in early stages of disease and retinal tubulation is present in advanced disease. Analysis of leukocyte RNA complements the high sensitivity of conventional sequencing of genomic DNA for mutation detection in this gene. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]

Leber Congenital Amaurosis (LCA) and Early Childhood Onset Severe Retinal Dystrophy are clinically and genetically heterogeneous retinal disorders characterised by visual impairment and nystagmus from birth or early infancy. We investigated the prevalence of sequence variants in AIPL1 in a large cohort of such patients (n = 392) and probed the likelihood of disease-causation of the identified variants, subsequently undertaking a detailed assessment of the phenotype of patients with disease-causing mutations. Genomic DNA samples were screened for known variants in the AIPL1 gene using a microarray LCA chip, with 153 of these cases then being directly sequenced. The assessment of disease-causation of identified AIPL1 variants included segregation testing, assessing evolutionary conservation and in silico predictions of pathogenicity. The chip identified AIPL1 variants in 12 patients. Sequencing of AIPL1 in 153 patients and 96 controls found a total of 46 variants, with 29 being novel. In silico analysis suggested that only 6 of these variants are likely to be disease-causing, indicating a previously unrecognized high degree of polymorphism. Seven patients were identified with biallelic changes in AIPL1 likely to be disease-causing. In the youngest subject, electroretinography revealed reduced cone photoreceptor function, but rod responses were within normal limits, with no measurable ERG in other patients. An increasing degree and extent of peripheral retinal pigmentation and degree of maculopathy was noted with increasing age in our series. AIPL1 is significantly polymorphic in both controls and patients, thereby complicating the establishment of disease-causation of identified variants. Despite the associated phenotype being characterised by early-onset severe visual loss in our patient series, there was some evidence of a degree of retinal structural and functional preservation, which was most marked in the youngest patient in our cohort. This data suggests that there are patients who have a reasonable window of opportunity for gene therapy in childhood. [ABSTRACT FROM AUTHOR]

Aim To report novel spectral domain optical coherence tomography (SD-OCT) findings and new mutational data in patients with 'cone dystrophy with supernormal rod electroretinogram', a recessive childhood onset retinal dystrophy consequent upon mutation in the KCNV2 gene. Design/methods This was a comparative case series study of 12 patients with clinical and/or electrophysiological findings in keeping with KCNV2 mutation. Clinical examination and electrophysiological testing results were reviewed. Fundus photography and autofluorescence imaging were performed. Retinal layer appearance and thickness were evaluated using SD-OCT. The coding region and introneexon boundaries of KCNV2 were screened by direct sequencing. Results Mutations in KCNV2 were detected in all families; five of these changes were novel. Pattern electroretinograms were undetectable and full-field electroretinograms showed findings specific for the disorder. SD-OCT demonstrated bilateral morphological changes, usually confined to the fovea. Four foveal SDOCT phenotypes were observed: (i) discontinuous inner and outer segment (IS/OS) junction reflectivity (6 patients), (ii) loss of IS/OS line and an optical gap in the foveola (2 patients); (iii) IS/OS junction disruption and profound foveal depth reduction, without optical gap and with preserved retinal pigment epithelium (RPE) complex (2 patients); and (iv) outer retina and RPE complex abnormalities (2 patients). Thinning of the neurosensory retina was observed in all eyes. Conclusion In KCNV2 retinopathy foveal morphological changes are evident on SD-OCT even in the early stages of disease. However, there appears to be a window of opportunity, before marked structural damage has occurred, during which novel therapeutic intervention, such as gene replacement therapy, may rescue retinal function. [ABSTRACT FROM AUTHOR]

Flecked-retina syndromes, including fundus flavimaculatus, fundus albipunctatus, and benign fleck retina, comprise a group of disorders with widespread or limited distribution of yellow-white retinal lesions of various sizes and configurations. Three siblings who have benign fleck retina and were born to consanguineous parents are the basis of this report. A combination of homozygosity mapping and exome sequencing helped to identify a homozygous missense mutation, c.133G>T (p.Gly45Cys), in PLA2G5, a gene encoding a secreted phospholipase (group V phospholipase A2). A screen of a further four unrelated individuals with benign fleck retina detected biallelic variants in the same gene in three patients. In contrast, no loss of function or common (minor-allele frequency>0.05%) nonsynonymous PLA2G5 variants have been previously reported (EVS, dbSNP, 1000 Genomes Project) or were detected in an internal database of 224 exomes (from subjects with adult onset neurodegenerative disease and without a diagnosis of ophthalmic disease). All seven affected individuals had fundoscopic features compatible with those previously described in benign fleck retina and no visual or electrophysiological deficits. No medical history of major illness was reported. Levels of low-density lipoprotein were mildly elevated in two patients. Optical coherence tomography and fundus autofluorescence findings suggest that group V phospholipase A2 plays a role in the phagocytosis of photoreceptor outer-segment discs by the retinal pigment epithelium. Surprisingly, immunohistochemical staining of human retinal tissue revealed localization of the protein predominantly in the inner and outer plexiform layers. [Copyright &y& Elsevier]

Purpose: To describe phenotypic variability and report novel mutational data in patients with mutation in RDH5 (fundus albipunctatus). Design: Retrospective case series. Participants: Nine patients from 8 families (aged 7–55 years) with night blindness and electrophysiologic or fundoscopic findings in keeping with RDH5 mutation were ascertained. Methods: Detailed ophthalmologic examination, fundus photography, fundus autofluorescence imaging, spectral domain optical coherence tomography (SD-OCT), and electrophysiologic assessment were performed. The coding region and intron-exon boundaries of RDH5 were analyzed. Main Outcome Measures: RDH5 mutation status and resultant clinical and functional characteristics. Results: Eleven mutations in RDH5 were detected in the 8 families in the study, with 9 of these changes being novel. Visual acuity was normal in all but 1 eye of a patient with adult-onset central visual loss. Most patients had white dots extending into the mid-periphery on fundus examination, consistent with fundus albipunctatus, but 1 patient had normal fundi. Autofluorescence imaging revealed an association between the white dots and the hyperautofluorescent foci in younger subjects. The overall autofluorescence signal appeared low in all patients. The SD-OCT changes included deposits associated with the white dots that extended from Bruch''s membrane to the external limiting membrane and focal loss of outer segments. Full-field electroretinogram (ERG) performed after standard dark adaptation showed moderate to severe generalized rod system dysfunction. Dim flash rod system ERGs were undetectable (N = 3) or subnormal (N = 6), but normalized after prolonged dark adaptation in 7 cases. Scotopic bright flash ERGs contained a reduced b:a ratio (“negative” ERG) in most cases; the use of a red stimulus under dark adaptation and extended recordings in the dark-adapted state in 1 patient identified dark-adapted cones as the probable source of the ERG signals. Photopic responses were abnormal in 6 of 9 cases. Conclusions: The clinical and electrophysiologic phenotype of patients with RDH5 retinopathy is variable. Mutations in RDH5 lead to reduced autofluorescence signal possibly because of absence of retinoid-derived fluorophores. The dark-adapted bright flash ERG is often electronegative and likely a manifestation of the dark-adapted cone system exposed in the absence of normal rod function. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]

Inherited retinal degenerations, including retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA), comprise a group of disorders showing high genetic and allelic heterogeneity. The determination of a full catalog of genes that can, when mutated, cause human retinal disease is a powerful means to understand the molecular physiology and pathology of the human retina. As more genes are found, remaining ones are likely to be rarer and/or unexpected candidates. Here, we identify a family in which all known RP/LCA-related genes are unlikely to be associated with their disorder. A combination of homozygosity mapping and exome sequencing identifies a homozygous nonsense mutation, c.496C>T (p.Arg166X), in a gene, KCNJ13, encoding a potassium channel subunit Kir7.1. A screen of a further 333 unrelated individuals with recessive retinal degeneration identified an additional proband, homozygous for a missense mutation, c.722T>C (p.Leu241Pro), in the same gene. The three affected members of the two families have been diagnosed with LCA. All have a distinct and unusual retinal appearance and a similar early onset of visual loss, suggesting both impaired retinal development and progressive retinal degeneration, involving both rod and cone pathways. Examination of heterozygotes revealed no ocular disease. This finding implicates Kir7.1 as having an important role in human retinal development and maintenance. This disorder adds to a small diverse group of diseases consequent upon loss or reduced function of inwardly rectifying potassium channels affecting various organs. The distinct retinal phenotype that results from biallelic mutations in KCNJ13 should facilitate the molecular diagnosis in further families. [Copyright &y& Elsevier]

Background: Macular degeneration is known to be a bilateral disease. This study set out to determine the symmetry of phenotype between eyes of patients with bilateral early AMD (or drusen) or late-stage AMD. This may be important information when considering the likelihood of anti-VEGF treatment. Methods: This prospective, observational, cross-sectional study graded the color fundus photographs of both eyes of 1,114 Caucasian patients with either early or late-stage AMD. Patients were recruited from a tertiary referral UK population. The main outcomes were phenotype, comparison of number, type and overall area of drusen in early AMD and symmetry of late AMD. Results: The overall agreement of phenotype in the entire cohort of patients was 53%, kappa statistic (κ)=0.31, (95% CI = 0.27-0.36). Within this group, a total of 271 patients were identified with bilateral soft and hard drusen (early AMD). Symmetry of phenotype within this group was high in terms of total of area of drusen (agreement = 79%, weighted κ = 0.75) and number of drusen. In those with bilateral geographic atrophy (GA), symmetry between area of GA was moderate (agreement 72%, weighted κ = 0.54), and in those with bilateral neovascular disease (choroidal neovascularization or pigment epithelial detachment), symmetry was poor (agreement 45%, weighted κ = 0.16). Out of the entire cohort, 62% ( n = 688) had neovascular disease in at least one eye and 37.5% of these had bilateral disease. Conclusions: The observed symmetry of phenotype between eyes with drusen appears to reduce in GA and neovascular forms of AMD. Overall, 53% of the cohort had symmetrical disease in terms of phenotype, 23% had neovascular disease in both eyes, 9.3% had GA in both eyes, and 39% of patients had neovascular disease in one eye and non-neovascular disease in the other. This may have implications for the potential need for anti-VEGF treatment of AMD in second eye involvement. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study is to image and describe the in vivo choroidal changes in various retinal dystrophies using the technique of enhanced depth imaging (EDI) optical coherence tomography (OCT) and to correlate these findings with the clinical appearance. Associations between choroidal change and genotype, visual acuity and results of retinal electrophysiology are also explored. Design: Retrospective observational case series. Methods: Twenty patients attending the medical retina clinics at Moorfields Eye Hospital underwent EDI OCT choroidal scans as part of the scanning protocol when they underwent OCT imaging with the Spectralis HRA and OCT. The choroidal images were obtained by moving the Spectralis camera close enough to obtain an inverted image of the retina. The scans were read by two experienced OCT readers assessing the choroidal thickness as well as the choroidal contour for focal areas of choroidal thinning corresponding to the areas of RPE/outer retinal atrophy. The spectrum of patients included those with Stargardt macular dystrophy, macular dystrophies secondary to known mutations such as peripherin/RDS, uncharacterised macular dystrophies, Best disease, bifocal chorioretinal atrophy, Bietti crystalline retinal dystrophy and choroideraemia. Results: The choroidal appearance was symmetrical in all patients who had both eyes scanned. Ten patients showed no choroidal thinning, five had focal mild to moderate choroidal thinning, three had focal severe choroidal thinning, and two patients had diffuse severe choroidal thinning. There was no association between choroidal thinning and visual acuity [Fisher's exact test, p = 0.350 (right eye), p = 1.000 (left eye)], or extent of retinal dysfunction on electrophysiology (Fisher's exact test, p = 1.000). Conclusion: Enhanced depth imaging using spectral domain OCT can be used to identify choroidal changes in inherited retinal disease. The pattern of choroidal change correlates well with the clinical appearance. It appears that the extent and pattern of choroidal thinning is dependent on the stage of the disease in some cases, and in others the causative gene defect. [ABSTRACT FROM AUTHOR]

Retinal degenerative diseases, such as retinitis pigmentosa and Leber congenital amaurosis, are a leading cause of untreatable blindness with substantive impact on the quality of life of affected individuals and their families. Mouse mutants with retinal dystrophies have provided a valuable resource to discover human disease genes and helped uncover pathways critical for photoreceptor function. Here we show that the rd11 mouse mutant and its allelic strain, B6-JR2845, exhibit rapid photoreceptor dysfunction, followed by degeneration of both rods and cones. Using linkage analysis, we mapped the rd11 locus to mouse chromosome 13. We then identified a one-nucleotide insertion (c.420-421insG) in exon 3 of the Lpcat1 gene. Subsequent screening of this gene in the B6-JR2845 strain revealed a seven-nucleotide deletion (c.14-20delGCCGCGG) in exon 1. Both sequence changes are predicted to result in a frame-shift, leading to premature truncation of the lysophosphatidylcholine acyltransferase-1 (LPCAT1) protein. LPCAT1 (also called AYTL2) is a phospholipid biosynthesis/remodeling enzyme that facilitates the conversion of palmitoyl-lysophosphatidylcholine to dipalmitoylphosphatidylcholine (DPPC). The analysis of retinal lipids from rd11 and B6-JR2845 mice showed substantially reduced DPPC levels compared with C57BL/6J control mice, suggesting a causal link to photoreceptor dysfunction. A follow-up screening of LPCAT1 in retinitis pigmentosa and Leber congenital amaurosis patients did not reveal any obvious disease-causing mutations. Previously, LPCAT1 has been suggested to be critical for the production of lung surfactant phospholipids and biosynthesis of platelet-activating factor in noninflammatory remodeling pathway. Our studies add another dimension to an essential role for LPCAT1 in retinal photoreceptor homeostasis. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which describes the visual acuity function following a retinal gene therapy with adeno-associated virus (AAV) vectors in patients with Leber's congenital amaurosis.

Complete congenital stationary night blindness (cCSNB) is associated with loss of function of rod and cone ON bipolar cells in the mammalian retina. In humans, mutations in NYX and GRM6 have been shown to cause the condition. Through the analysis of a consanguineous family and screening of nine additional pedigrees, we have identified three families with recessive mutations in the gene TRPM1 encoding transient receptor potential cation channel, subfamily M, member 1, also known as melastatin. A number of other variants of unknown significance were found. All patients had myopia, reduced central vision, nystagmus, and electroretinographic evidence of ON bipolar cell dysfunction. None had abnormalities of skin pigmentation, although other skin conditions were reported. RNA derived from human retina and skin was analyzed and alternate 5′ exons were determined. The most 5' exon is likely to harbor an initiation codon, and the protein sequence is highly conserved across vertebrate species. These findings suggest an important role of this specific cation channel for the normal function of ON bipolar cells in the human retina. [ABSTRACT FROM AUTHOR]

We describe a distinct retinal disorder, autosomal-recessive bestrophinopathy (ARB), that is consequent upon biallelic mutation in BEST1 and is associated with central visual loss, a characteristic retinopathy, an absent electro-oculogram light rise, and a reduced electroretinogram. Heterozygous mutations in BEST1 have previously been found to cause the two dominantly inherited disorders, Best macular dystrophy and autosomal-dominant vitreoretinochoroidopathy. The transmembrane protein bestrophin-1, encoded by BEST1, is located at the basolateral membrane of the retinal pigment epithelium in which it probably functions as a Cl-1 channel. We sequenced BEST1 in five families, identifying DNA variants in each of ten alleles. These encoded six different missense variants and one nonsense variant. The alleles segregated appropriately for a recessive disorder in each family. No clinical or electrophysiological abnormalities were identified in any heterozygotes. We conducted whole-cell patch-clamping of HEK293 cells transfected with bestrophin-1 to measure the Cl-1 current. Two ARB missense isoforms severely reduced channel activity. However, unlike two other alleles previously associated with Best disease, cotransfection with wild-type bestrophin-1 did not impair the formation of active wild-type bestrophin-1 channels, consistent with the recessive nature of the condition. We propose that ARB is the null phenotype of bestrophin-1 in humans. [ABSTRACT FROM AUTHOR]

The rd3 mouse is one of the oldest identified models of early-onset retinal degeneration. Using the positional candidate approach, we have identified a CrT substitution in a novel gene, Rd3, that encodes an evolutionarily conserved protein of 195 amino acids. The rd3 mutation results in a predicted stop codon after residue 106. This change is observed in four rd3 lines derived from the original collected mice but not in the nine wild-type mouse strains that were examined. Rd3 is preferentially expressed in the retina and exhibits increasing expression through early postnatal development. In transiently transfected COS-1 cells, the RD3-fusion protein shows subnuclear localization adjacent to promyelocytic leukemia-gene-product bodies. The truncated mutant RD3 protein is detectable in COS-1 cells but appears to get degraded rapidly. To explore potential association of the human RD3 gene at chromosome 1q32 with retinopathies, we performed a mutation screen of 881 probands from North America, India, and Europe. In addition to several alterations of uncertain significance, we identified a homozygous alteration in the invariant G nucleotide of the RD3 exon 2 donor splice site in two siblings with Leber congenital amaurosis. This mutation is predicted to result in premature truncation of the RD3 protein, segregates with the disease, and is not detected in 121 ethnically matched control individuals. We suggest that the retinopathy-associated RD3 protein is part of subnuclear protein complexes involved in diverse processes, such as transcription and splicing. [ABSTRACT FROM AUTHOR]

Leber congenital amaurosis (LCA) is one of the main causes of childhood blindness. To date, mutations in eight genes have been described, which together account for ~45% of LCA cases. We localized the genetic defect in a consanguineous LCA-affected family from Quebec and identified a splice defect in a gene encoding a centrosomal protein (CEP290). The defect is caused by an intronic mutation (c.2991+1655A→G) that creates a strong splice-donor site and inserts a cryptic exon in the CEP290 messenger RNA. This mutation was detected in 16 (21%) of 76 unrelated patients with LCA, either homozygously or in combination with a second deleterious mutation on the other allele. CEP290 mutations therefore represent one of the most frequent causes of LCA identified so far. [ABSTRACT FROM AUTHOR]

Purpose: To determine the underlying molecular genetic basis of a retinal dystrophy identified in a 4-generation family and to examine the phenotype and the degree of intrafamilial variability. Design: Prospective case series. Participants: Six affected individuals from a nonconsanguineous British family. Methods: Detailed ophthalmologic examination, color fundus photography, autofluorescence imaging, and electrophysiologic assessment were performed. Blood samples were taken for DNA extraction, and mutation screening of GUCA1A, the gene encoding guanylate cyclase-activating protein 1 (GCAP1), was undertaken. Results: All affected subjects complained of mild photophobia and reduced central and color vision. Onset was between the third and fifth decade, with subsequent gradual deterioration of visual acuity and color vision. Visual acuity ranged between 6/9 and counting fingers. Color vision was either absent or markedly reduced along all 3 color axes. A range of macular appearances was seen, varying from mild retinal pigment epithelial disturbance to extensive atrophy. Electrophysiologic testing revealed a range of electrophysiologic abnormalities: isolated cone electroretinography abnormalities, reduced cone and rod responses (with cone loss greater than rod), and isolated macular dysfunction. The 4 coding exons of GUCA1A were screened for mutations in affected and unaffected family members. A single transition, A319G, causing a nonconservative missense substitution, Tyr99Cys, segregated uniquely in all affected subjects. Conclusions: The Tyr99Cys GUCA1A mutation has been previously shown to cause autosomal dominant progressive cone dystrophy. This is the first report of this mutation also causing both cone-rod dystrophy and isolated macular dysfunction. The phenotypic variation described here exemplifies the intrafamilial heterogeneity of retinal dysfunction that can be observed in persons harboring the same mutation and chromosomal segment. [Copyright &y& Elsevier]

Age-related macular maculopathy (ARM) and age-related macular degeneration (AMD) are the leading causes of blindness in the Western world. Despite the magnitude of this clinical problem, very little is known about the pathogenesis of the disease. In this study, we analysed the sera (using indirect immunohistochemistry and Western blot analysis) from a very large cohort of such patients and normal age-matched controls to detect circulating anti-retinal antibodies. Patients with bilateral drusen ( n = 64) and with chorioretinal neovascularization (CNV) ( n = 51) were recruited in addition to age-matched control subjects ( n = 39). The sera were analysed for anti-retinal immunoglobulins on retinal sections. The data were then correlated with the clinical features graded according to the International Classification and Grading System of ARM and AMD. The sera of patients with drusen (93·75%) and CNV (82·27%) were found to have a significantly ( P = 0·02) higher titre of autoantibodies to the retina in comparison with controls (8·69%), indicating significant evidence of involvement of the immune process in early stages of AMD. Subsequent statistical analysis of the drusen group showed significant progressive staining ( P = 0·0009) in the nuclei layers from early to late stages of ARM. Western blotting confirmed the presence of anti-retinal immunoglobulins to retinal antigens. As anti-retinal immunoglobulins are present in patients with bilateral drusen and exudative AMD, these antibodies could play a significant role in the pathogenesis of AMD. Whilst we do not have evidence that these antibodies precede disease onset, the possibility that their presence might contribute to disease progression needs to be investigated. Finally, the eventual identification of the target antigens detected by these antibodies may permit the future development of new diagnostic methods for ARM and AMD. [ABSTRACT FROM AUTHOR]

X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research. [ABSTRACT FROM AUTHOR]

Biallelic pathogenic variants in solute carrier family 38 member 8, SLC38A8, cause a pan-ocular autosomal recessive condition known as foveal hypoplasia 2, FVH2, characterised by foveal hypoplasia, nystagmus and optic nerve chiasmal misrouting. Patients are often clinically diagnosed with ocular albinism, but foveal hypoplasia can occur in several other ocular disorders. Here we describe nine patients from seven families who had molecularly confirmed biallelic recessive variants in SLC38A8 identified through whole genome sequencing or targeted gene panel testing. We identified four novel sequence variants (p.(Tyr88*), p.(Trp145*), p.(Glu233Gly) and c.632+1G>A). All patients presented with foveal hypoplasia, nystagmus and reduced visual acuity; however, one patient did not exhibit any signs of chiasmal misrouting, and three patients had features of anterior segment dysgenesis. We highlight these findings in the context of 30 other families reported to date. This study reinforces the importance of obtaining a molecular diagnosis in patients whose phenotype overlap with other inherited ocular conditions, in order to support genetic counselling, clinical prognosis and family planning. We expand the spectrum of SLC38A8 mutations which will be relevant for treatment through future genetic-based therapies. [ABSTRACT FROM AUTHOR]

Background: Characterisation of preserved autofluorescence (PAF) area in choroideremia (CHM) and its validity for monitoring disease progression in clinical trials is of importance. Methods: Eighty patients with molecularly confirmed CHM were recruited. PAF area was measured manually by 2 graders and half-life was calculated based on exponential decay model. Results: Mean age at baseline and follow-up examination was 38.1 (range, 10–69) and 40.7 (range, 11–70) years. Mean follow-up interval was 29 months (range, 6–104). The median LogMAR visual acuity was 0.10 (OD) and 0.18 (OS). Interobserver repeatability for PAF area was −0.99 to 1.03 mm2 (−6.46 to 6.49% of area). There was a statistically significant relationship between age and rate of PAF area loss (r2 = 0.28, p = 0.012). The half-life for PAF area was 13.7 years (range, 1.7–216.0 years). The correlation between half-life and age was stronger than between half-life and log transformed baseline PAF area, although neither was statistically significant. Conclusions: The intra- and inter-observer PAF area measurement variability provides a baseline change, which must be overcome in a clinical trial if this metric were to be used. Treatments must slow progression to alter the exponential decay in a timely manner accounting for naturally slow progression patterns. [ABSTRACT FROM AUTHOR]

The H402 allele of the CFH gene is an established risk factor for age-related maculopathy (ARMD) in Caucasians, accounting for approximately 60% of the genetic risk at the population level.1 In general, the advanced forms of ARMD are rare in Black populations in Africa, as well as Black populations who have lived for generations in the United States or the West Indies, although there are reports that the earlier forms such as drusen may not be all that uncommon.2, 3, 4 The aim of the present study was to estimate the frequency of the C allele of the CFH Y402H variant in an aged South African Black Xhosa population and to describe the evidence of ARMD found. [ABSTRACT FROM AUTHOR]

Mutations in KCNJ13 are associated with two retinal disorders; Leber congenital amaurosis (LCA) and snowflake vitreoretinal degeneration (SVD). We describe a novel fibrovascular proliferation in the retina of two affected members of a KCNJ13 -related LCA family with a homozygous c.458C > T, p.(Thr153Ile) missense mutation. Optical coherence tomography retinal imaging of the kcnj13 mutant zebrafish (obelix td15 c.502T > C, p.[Phe168Leu]) revealed a late onset retinal degeneration at 12 months, with retinal thinning and associated retinovascular changes, including increased vessel calibre and vitreous deposits. Both human and zebrafish variants are missense and located within the conserved transmembrane M2 protein domain, suggesting that disruption of this region may contribute to retinovascular changes as an additional feature to the previously described LCA phenotype. Close monitoring of other patients with similar mutations may be required to minimise the ensuing retinal damage. • Patients with KCNJ13 c.458C>T, p.(Thr153Ile) mutations were examined for retinovascular abnormalities. • A novel fibrovascular proliferation was observed in the retina of two siblings with KCNJ13 -Leber congenital amaurosis. • kcnj13 mutant zebrafish (obelix td15 ) showed a retinal degeneration with associated retinovascular changes. • Both human and zebrafish variants are missense and located within the transmembrane M2 protein domain. • This retinovascular complication should be considered within the clinical spectrum of KCNJ13 -related retinal disease. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented which discusses the case of a male patient with cone-rod dystrophy due to homozygous mutation in ADAM9 gene.

A response from the authors of the article "Inositol 1,4,5-Trisphosphate Receptors and Human Left Ventricular Myocytes" is presented.

Several letters to the editor are presented in response to the article "High Risk Clinical Characteristics for Subarachnoid Haemorrhage in Patients with Acute Headache: Prospective Cohort Study," by J. J. Perry and colleagues, published in the October 28, 2010 issue.

A letter to the editor is presented that describes a new phenotype of macular disease in a patient with confirmed mitochondrial A3243G point mutation.

The article discusses the guidelines regarding the clinical utility of genetic testing for the disease choroideremia or tapetochoroidal dystrophy. Topics discussed include the mutational spectrum caused by mutations in the CHM gene, life-time risk of developing the disease if the test is positive, and a molecular diagnosis in an affected individual concerning the disease's genetic situation.

Background: Usher Syndrome is the leading cause of inherited deaf-blindness. It is divided into three subtypes, of which the most common is Usher type 2, and the USH2A gene accounts for 75-80% of cases. Despite recent sequencing strategies, in our cohort a significant proportion of individuals with Usher type 2 have just one heterozygous disease-causing mutation in USH2A, or no convincing disease-causing mutations across nine Usher genes. The purpose of this study was to improve the molecular diagnosis in these families by screening USH2A for duplications, heterozygous deletions and a common pathogenic deep intronic variant USH2A: c.7595-2144A>G.Methods: Forty-nine Usher type 2 or atypical Usher families who had missing mutations (mono-allelic USH2A or no mutations following Sanger sequencing of nine Usher genes) were screened for duplications/deletions using the USH2A SALSA MLPA reagent kit (MRC-Holland). Identification of USH2A: c.7595-2144A>G was achieved by Sanger sequencing. Mutations were confirmed by a combination of reverse transcription PCR using RNA extracted from nasal epithelial cells or fibroblasts, and by array comparative genomic hybridisation with sequencing across the genomic breakpoints.Results: Eight mutations were identified in 23 Usher type 2 families (35%) with one previously identified heterozygous disease-causing mutation in USH2A. These consisted of five heterozygous deletions, one duplication, and two heterozygous instances of the pathogenic variant USH2A: c.7595-2144A>G. No variants were found in the 15 Usher type 2 families with no previously identified disease-causing mutations. In 11 atypical families, none of whom had any previously identified convincing disease-causing mutations, the mutation USH2A: c.7595-2144A>G was identified in a heterozygous state in one family. All five deletions and the heterozygous duplication we report here are novel. This is the first time that a duplication in USH2A has been reported as a cause of Usher syndrome.Conclusions: We found that 8 of 23 (35%) of 'missing' mutations in Usher type 2 probands with only a single heterozygous USH2A mutation detected with Sanger sequencing could be attributed to deletions, duplications or a pathogenic deep intronic variant. Future mutation detection strategies and genetic counselling will need to take into account the prevalence of these types of mutations in order to provide a more comprehensive diagnostic service. [ABSTRACT FROM AUTHOR]

Purpose: To examine retinal structure and changes in photoreceptor intensity after dark adaptation in patients with complete congenital stationary night blindness and Oguchi disease. Design: Prospective, observational case series. Methods: We recruited 3 patients with complete congenital stationary night blindness caused by mutations in GRM6, 2 brothers with Oguchi disease caused by mutations in GRK1, and 1 normal control. Retinal thickness was measured from optical coherence tomography images. Integrity of the rod and cone mosaic was assessed using adaptive optics scanning light ophthalmoscopy. We imaged 5 of the patients after a period of dark adaptation and examined layer reflectivity on optical coherence tomography in a patient with Oguchi disease under light- and dark-adapted conditions. Results: Retinal thickness was reduced in the parafoveal region in patients with GRM6 mutations as a result of decreased thickness of the inner retinal layers. All patients had normal photoreceptor density at all locations analyzed. On removal from dark adaptation, the intensity of the rods (but not cones) in the patients with Oguchi disease gradually and significantly increased. In 1 Oguchi disease patient, the outer segment layer contrast on optical coherence tomography was 4-fold higher under dark-adapted versus light-adapted conditions. Conclusions: The selective thinning of the inner retinal layers in patients with GRM6 mutations suggests either reduced bipolar or ganglion cell numbers or altered synaptic structure in the inner retina. Our finding that rods, but not cones, change intensity after dark adaptation suggests that fundus changes in Oguchi disease are the result of changes within the rods as opposed to changes at a different retinal locus. [Copyright &y& Elsevier]

The article offers information on the genetic mutations in the BEST1-related dystrophies or Bestrophinopathies. It informs that only single families have been identified as having BEST1 mutations. It reports that the p.Thr6Pro, mutation associated with the Best disease, has a particularly high frequency in the Netherlands.

Purpose: Enhanced S-cone syndrome (ESCS), also known as Goldmann-Favre syndrome, is a progressive retinal degeneration that frequently presents with night blindness and nummular pigment clumping around the vascular arcades and is caused by recessive mutations in the photoreceptor-specific NR2E3 transcription factor. A unique feature of this disease is the development of retinoschisis of the macula. This study used fine anatomic and functional assessments within this region to determine whether the loss of retinal function was due to progressive schisis or a primary photoreceptor loss, similar to other rod-cone dystrophies. Design: Cross-sectional, prospective study. Participants: Nine probands (n=18 eyes) and 3 controls (n=6 eyes) were studied at Moorfields Eye Hospital in London, United Kingdom. Methods: Histories were obtained and visual acuity was measured using Early Treatment Diabetic Retinopathy Study protocol. Autofluorescence (AF), fundus photography, and spectral domain optical coherence tomography (OCT) imaging were co-registered to detailed microperimetry (Nidek MP1; NAVIS software version 1.7.2; Nidek Technologies, Padova, Italy) data for statistical analysis. Main Outcome Measures: Retinal sensitivity (decibels) in a customized test grid of the macula; retinal structure assessed with OCT and AF. Results: Patients were divided into 3 cohorts roughly based on life span and documentation of schisis: (1) no schisis, childhood; (2) macular schisis, young adults; (3) resolved schisis, older adults. Retinal sensitivity was significantly attenuated in those with schisis and did not recover in those whose schisis had resolved despite retinal thickness comparable to that of controls. All probands exhibited loss of AF peripherally (and corresponding loss of retinal sensitivity), but there was relative preservation of AF within the macula. Conclusions: Development of macular retinoschisis in ESCS is an important feature of the disease and contributes to attenuated retinal sensitivity that persists after resolution of retinoschisis. The central macula appears to be compromised more by foveoschisis than photoreceptor loss. In contrast, the peripheral retina (ordinarily a rod-rich region) is affected early in the disease process and degenerates rapidly because of photoreceptor loss. Thus, 2 distinct mechanisms of retinal degeneration may exist in ESCS, corresponding to regions of the retina that may experience either normal or abnormal photoreceptor development. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]

Purpose: To examine the phenotypes of 8 patients with evidence of cone dysfunction and normal color vision (characteristic features of both oligocone trichromacy and bradyopsia), and subsequently to screen RGS9 and R9AP for disease-causing mutations. Design: Retrospective case series. Participants: Eight affected individuals from 7 families. Methods: Ophthalmologic examination, color vision testing, fundus photography, and detailed electrophysiologic assessment were undertaken. Blood samples were taken for DNA extraction from affected subjects and, where possible, unaffected relatives. Mutation screening of RGS9 and R9AP was performed. Main Outcome Measures: Detailed clinical, electrophysiologic, and molecular genetic findings. Results: All 8 patients had normal ocular examination results, with visual acuity ranging from 6/12 to 6/18. Four subjects were found to harbor mutations in RGS9 or R9AP, with 3 of the identified sequence variants being novel. Three subjects, 2 Pakistani sisters and an Afghani female, had mutations in R9AP. A novel homozygous nonsense mutation, p.G205fs, was identified in the simplex case, and a second novel homozygous in-frame deletion, p.D32_Q34del, was found in the 2 sisters. The remaining patient, a British male, had a compound heterozygous mutation in RGS9 (p.R128X/p.W299R). The mutation p.R128X represents the first nonsense mutation reported in RGS9. The 4 mutation-positive subjects had concordant characteristic previously described electrophysiologic findings that were not present in the 4 individuals in whom mutations were not identified. Novel findings associated with these mutation-positive patients included that they all showed electroretinogram evidence of severe cone system dysfunction under photopic conditions but normal cone function to a red flash under scotopic conditions. Such findings seem unique for the disorder. Conclusions: This is the first report describing a nonsense mutation in RGS9. We have established novel electrophysiologic observations associated with RGS9 and R9AP mutations, including those relating to dark-adapted cone function and S-cone function. Patients with either RGS9/R9AP mutations (bradyopsia) or oligocone trichromacy have very similar clinical phenotypes, characterized by stationary cone dysfunction, mild photophobia, normal color vision, lack of nystagmus, and normal fundi. The distinctive electrophysiologic features associated with RGS9 and R9AP mutations enable directed genetic screening. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]