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The shortage of specialists in SHI-accredited medical care is increasingly affecting medical assistants (MFA) in medical practices and Medical Care Center (MVZ). Training can mitigate the associated problems in the future, but currently only 42% of practices provide training. A survey of a sample of large ophthalmic centers was conducted to test the hypothesis that larger practices and MVZs provide disproportionate training. In addition, an interaction between ownership (physician-owned (äE); third-party owned (F)) and training engagement was evaluated. In a questionnaire-based complete survey (2022) of large ophthalmic centers of different ownerships organized in a network, the training rate by main operating site (HBS), the number of MFA trainees (MFA-A) per HBS, staffing problems and planned change in training commitment were collected. The distribution measures of the quantitative data were analyzed overall and separately by sponsoring organization and tested for significance.Results were compared to data from a representative survey (2020/2021) of all practices and MVZs. In order to determine the proportion of all ophthalmic MFA-A accounted for by the sample, their total number was determined in an extrapolation. The training rate of the total of 100 HBS of the 14 surveyed centers (11 äE, 3 F) of the sample was 82% (äE: 93%, F: 79%), which was higher than the representative survey (41%). In the sample, there were on average 5.9 MFA-A per HBS (äE: 5.6, F: 7.1), in the comparative survey 1.5. 50% of the centers in the sample reported staffing problems, 25% wanted to expand their training commitment; the comparative values of the representative survey were 11% for both parameters. Stratified by sponsorship, neither training rate nor MFA-A per HBS showed significant differences. According to projections, there were nearly 1,966 MFA-A working in ophthalmology in 2021, of which 19.5% were at centers in the study population. Of all the MFA-A in the sample, 71% were at the significantly larger centers by number of HBS owned by third-party. The survey confirms the positive correlation between the size of practices and MVZ and commitment to training. There are no significant differences according to the ownership of organization.
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Oftalmologia , Alemanha , Oftalmologia/educação , Oftalmologia/estatística & dados numéricos , Inquéritos e Questionários , Humanos , Assistentes de Oftalmologia/estatística & dados numéricos , Assistentes de Oftalmologia/educaçãoRESUMO
This review provides an overview of retinal vascular disorders that are less frequent in Germany and Europe compared to diabetic retinopathy and retinal venous or arterial occlusive disorders. The knowledge of these disorders is important for the differential diagnosis of retinal vascular disorders as well as potentially associated systemic disorders. In the current part one epidemiology, pathophysiology, clinical presentation, and therapy are discussed for hypertensive retinochoroidopathy, ocular ischemic syndrome, retinal alterations in sickle cell disease, Eales disease, radiation retinopathy, peripheral exudative hemorrhagic chorioretinopathy, and retinal disorders associated with pregnancy.
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Inherited retinal diseases can result from various genetic defects and are one of the leading causes for blindness in the working-age population. The present study aims to provide a comprehensive description of changes in retinal structure associated with phenotypic disease entities and underlying genetic mutations. Full macular spectral domain optical coherence tomography scans were obtained and manually segmented in 16 patients with retinitis pigmentosa, 7 patients with cone−rod dystrophy, and 7 patients with Stargardt disease, as well as 23 age- and sex-matched controls without retinal disease, to assess retinal layer thicknesses. As indicated by generalized least squares models, all IRDs were associated with retinal thinning (p < 0.001), especially of the outer nuclear layer (ONL, p < 0.001). Except for the retinal nerve fiber layer, such thinning was associated with a reduced visual acuity (p < 0.001). These advances in our understanding of ultrastructural retinal changes are important for the development of gene-, cell-, and optogenetic therapy. Longitudinal studies are warranted to describe the temporal component of those changes.
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Degeneração Retiniana , Retinose Pigmentar , Humanos , Tomografia de Coerência Óptica/métodos , Retina/diagnóstico por imagem , Retinose Pigmentar/genética , Doença de Stargardt/genéticaRESUMO
Exogenously induced retinopathies can be caused by consumation of stimulating substances, systemic or ocular medications, vaccinations, light or irradiation. Some of the effects are transient, whereas other effects induce irreversible toxic reactions. Retinal damage may develop either acutely with obvious relation to the damaging cause, but often may take a long duration of repeated use of a substance or medication. External stimulants (e.g. nicotine, alcohol, poppers, methanol) are the most frequent cause of exogenously induced retinal damage. Side effects from systemic drugs (e.g. hydroxychloroquine, ethambutol, MEK-, ERK-, FLT3-, checkpoint inhibitors, didanosin, pentosanpolysulfat sodium) or intravitreally applied drugs (e.g. antibiotics, VEGF-inhibitors) are less frequent. Ocular side effects associated with vaccinations are rare. Ambient light sources induce no damaging effects on the retina. Incorrect use of technical or medical light sources (e.g. laser pointers) without adherence to safety recommendations or unshielded observation of the sun might induce permanent retinal damage. Local or external irradiation might induce retinal vascular damage resulting in radiation retinopathy.
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Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Oftalmopatias , Doenças Retinianas , Humanos , Doenças Retinianas/induzido quimicamente , Retina , Poliéster Sulfúrico de Pentosana/efeitos adversos , Hidroxicloroquina/efeitos adversosRESUMO
Blue cone monochromacy (BCM) is an X-linked retinal disorder characterized by low vision, photoaversion, and poor color discrimination. BCM is due to the lack of long-wavelength-sensitive and middle-wavelength-sensitive cone photoreceptor function and caused by mutations in the OPN1LW/OPN1MW gene cluster on Xq28. Here, we investigated the prevalence and the landscape of submicroscopic structural variants (SVs) at single-base resolution in BCM patients. We found that about one-third (n = 73) of the 213 molecularly confirmed BCM families carry an SV, most commonly deletions restricted to the OPN1LW/OPN1MW gene cluster. The structure and precise breakpoints of the SVs were resolved in all but one of the 73 families. Twenty-two families-all from the United States-showed the same SV, and we confirmed a common ancestry of this mutation. In total, 42 distinct SVs were identified, including 40 previously unreported SVs, thereby quadrupling the number of precisely mapped SVs underlying BCM. Notably, there was no "region of overlap" among these SVs. However, 90% of SVs encompass the upstream locus control region, an essential enhancer element. Its minimal functional extent based on deletion mapping in patients was refined to 358 bp. Breakpoint analyses suggest diverse mechanisms underlying SV formation as well as in one case the gene conversion-based exchange of a 142-bp deletion between opsin genes. Using parsimonious assumptions, we reconstructed the composition and copy number of the OPN1LW/OPN1MW gene cluster prior to the mutation event and found evidence that large gene arrays may be predisposed to the occurrence of SVs at this locus.
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Defeitos da Visão Cromática , Opsinas de Bastonetes , Defeitos da Visão Cromática/genética , Deleção de Genes , Humanos , Família Multigênica/genética , Células Fotorreceptoras Retinianas Cones , Opsinas de Bastonetes/genéticaRESUMO
Near-infrared autofluorescence (NIA) is a non-invasive retinal imaging technique for examination of the retinal pigment epithelium (RPE) based on the autofluorescence of melanin. Melanin has several functions within the RPE cells, in one of them it serves as a protective antioxidative factor within the RPE cells and is involved in the phagocytosis of photoreceptor outer segments. Disorders that affect the photoreceptor-RPE complex result in alterations of RPE cells which are detectable by alterations of NIA. Therefore, NIA allows to detect early alterations in inherited and acquired chorioretinal disorders, frequently prior to ophthalmoscopical visualisation and often prior to alterations in lipofuscin associated fundus autofluorescence (FAF) or optical coherence tomography (OCT). Although NIA and FAF relate to disorders affecting the RPE, findings between both imaging methods differ and the area involved has been demonstrated to be larger in NIA compared to FAF in several disorders (e.g., age-related macular degeneration, retinitis pigmentosa, ABCA4-gene associated Stargardt disease and cone-rod dystrophy, light damage), indicating that NIA detects earlier alterations compared to FAF. In addition, due to the absence of blue-light filtering which limits foveal visualisation in FAF, foveal alterations can be much better detected using NIA. A reduced subfoveal NIA intensity is the earliest sign of autosomal dominant BEST1-associated disease, when FAF and OCT are still normal. In other disorders, a normal subfoveal NIA intensity is associated with good visual acuity. This review summarizes the present knowledge on NIA and demonstrates biomarkers for various chorioretinal disorders.
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Melaninas , Epitélio Pigmentado da Retina , Transportadores de Cassetes de Ligação de ATP , Bestrofinas , Angiofluoresceinografia/métodos , Fundo de Olho , Humanos , Lipofuscina/metabolismo , Melaninas/metabolismo , Epitélio Pigmentado da Retina/diagnóstico por imagem , Tomografia de Coerência Óptica/métodosAssuntos
Medicina do Adolescente , Neonatologia , Oftalmologistas , Cuidados Críticos , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Pediatras , RetinaRESUMO
Achromatopsia (ACHM) is a congenital cone photoreceptor disorder characterized by impaired color discrimination, low visual acuity, photosensitivity, and nystagmus. To date, six genes have been associated with ACHM (CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, and ATF6), the majority of these being implicated in the cone phototransduction cascade. CNGA3 encodes the CNGA3 subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors and is one of the major disease-associated genes for ACHM. Herein, we provide a comprehensive overview of the CNGA3 variant spectrum in a cohort of 1060 genetically confirmed ACHM patients, 385 (36.3%) of these carrying "likely disease-causing" variants in CNGA3. Compiling our own genetic data with those reported in the literature and in public databases, we further extend the CNGA3 variant spectrum to a total of 316 variants, 244 of which we interpreted as "likely disease-causing" according to ACMG/AMP criteria. We report 48 novel "likely disease-causing" variants, 24 of which are missense substitutions underlining the predominant role of this mutation class in the CNGA3 variant spectrum. In addition, we provide extensive in silico analyses and summarize reported functional data of previously analyzed missense, nonsense and splicing variants to further advance the pathogenicity assessment of the identified variants.
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Defeitos da Visão Cromática , Canais de Cátion Regulados por Nucleotídeos Cíclicos , Defeitos da Visão Cromática/genética , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Humanos , Mutação , Células Fotorreceptoras Retinianas ConesRESUMO
BACKGROUND: The diagnostic process of inherited retinal dystrophies (IRD) is impeded by their low prevalence and the variability of the clinical presentations; however, for patients a valid diagnosis is vital for future planning and evaluating the potential of an appropriate early treatment to delay disease progression. OBJECTIVE: Aim of the current study was to outline the patients' journeys until they receive the final diagnosis. This should help uncover diagnostic shortcomings and highlight potential for improvement with respect to the use of genetic diagnostic testing. MATERIAL AND METHODS: Data were collected by questionnaires and an online survey conducted by the self-help association PRO RETINA Deutschland e.â¯V. among patients with IRD. Data were analyzed by descriptive statistics. RESULTS: From 15 March to 22 April 2021, 183 questionnaires were completed and 42 online interviews conducted. The surveyed population consisted of 48% female patients, mean age was 55 years and first symptoms occurred at a mean age of 22 years. On average about 14 years passed from first symptoms until final diagnosis. Only 66% of the patients reported that they had received at least 1 diagnostic genetic testing; less than half of the patients (47%) received genetic counseling. The huge majority of patients (85%) would be interested in gene therapy. CONCLUSION: From the perspective of affected patients, a shortening of the time to diagnosis, the use of molecular genetic testing and the offer of genetic counseling are important to improve patient care for patients with IRD.
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Distrofias Retinianas , Adulto , Feminino , Aconselhamento Genético , Testes Genéticos/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Biologia Molecular , Retina , Distrofias Retinianas/diagnóstico , Adulto JovemRESUMO
Retinopathy of prematurity (ROP) is a leading cause of preventable childhood blindness. This proliferative retinal vascular disease affects only prematurely born infants. Major risk factors include low gestational age and prolonged postnatal oxygen supplementation. ROP screening allows for timely identification of treatment-requiring infants and thus significantly reduces the risk of severe visual impairment and blindness from ROP. Current treatment options comprise retinal laser coagulation and intravitreal anti-vascular endothelial growth factor (VEGF) therapy. We provide a review of scientific data and current treatment recommendations, with special attention to the updated German guideline on ROP screening, the statement of the German ophthalmological societies on anti-VEGF therapy of ROP, and the new third edition of the International Classification of Retinopathy of Prematurity (ICROP3).
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Retinopatia da Prematuridade , Criança , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Injeções Intravítreas , Fotocoagulação a Laser , Retinopatia da Prematuridade/diagnóstico , Retinopatia da Prematuridade/terapia , Fator A de Crescimento do Endotélio VascularRESUMO
PURPOSE: The aim of this study was to compare the complication rates between surgery performed using digital heads-up 3D system (3D group) and a conventional binocular microscope-based system (BM group) in a large series of cataract operations performed by the same surgeon. METHODS: This retrospective analysis included a consecutive series of 2,000 cataract operations. The 3D group included n = 1,000 operations performed immediately following the introduction of a 3D system (Alcon Ngenuity). For comparison, the last n = 1,000 operations performed with a binocular microscope were included in the BM group. The 3D system was adapted to the existing microscope so that the microscope optics remained unchanged. The In both groups, the surgical techniques used were either phacoemulsification or femtosecond laser cataract surgery. Complications were recorded and analyzed retrospectively. RESULTS: The proportion of femto-laser cataract operations was 19.8% in the 3D group and 18.6% in the BM group. Capsule rupture occurred in 10 eyes (3D: n = 4 (0.4%), anterior vitrectomy: n = 2, pars plana vitrectomy: n = 1; BM: n = 6 cases (0.6%), anterior vitrectomy: n = 4, pars plana vitrectomy: n = 1). A short-term iris prolapse occurred in 3 eyes (3D: n = 2, BM: n = 1). Zonulolysis occurred in 2 eyes (3D: n = 1, BM: n = 1). Overall, there was no statistically significant difference between the two groups (p > 0.5). There was no significant increase in the duration of surgery following the switch to the 3D technique. CONCLUSION: In a large series of 2000 eyes, there was no significant difference between 3D and BM surgery in terms of the safety profile during cataract surgery. 3D surgery can, therefore, be used for cataract operations without additional risk.
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Extração de Catarata , Catarata , Facoemulsificação , Catarata/complicações , Extração de Catarata/efeitos adversos , Humanos , Facoemulsificação/efeitos adversos , Facoemulsificação/métodos , Estudos Retrospectivos , Acuidade Visual , Vitrectomia/métodosRESUMO
PURPOSE: To evaluate macular vascular abnormalities in patients with macular dystrophies (MD) and retinitis pigmentosa (RP) through application of optical coherence tomography angiography (OCT-A). METHODS: In this retrospective study, patients with MD and RP were examined by OCT-A and compared to healthy individuals. OCT-A images were analyzed regarding the diameter and surface area of the foveal avascular zone (FAZ) as well as flow (FL) in different retinal layers (superficial vascular complex (SVC), intermediate capillary complex (ICP), deep capillary complex (DCP), choriocapillaris (CC), and choroid (CD)). RESULTS: Twenty-one patients with MD, 21 patients with RP without macular edema (RPnE), 8 patients with RP with edema (RPwE), and 41 healthy individuals were enrolled. The group of MD and RPnE patients showed none or only minor changes in FAZ. In RPwE patients, the FAZ was significantly smaller in vertical and horizontal measurements and surface area in SVC, whereas it was markedly enlarged in ICP. FL was significantly reduced compared to healthy individuals by an average of 13.2% in CD, 14.2% in CC, and 8.4% in DCP in all patient groups. In ICP, the reduction was 9.2% for RPnE and 12.7% for RPwE patients. The SVC showed reduced FL in the MD (8.1%) and RPnE (10.3%) group. CONCLUSIONS: OCT-A is a valuable tool to examine retinal vascular abnormalities in patients with MD and RP. OCT-A revealed a reduced flow in various retinal layers in MD, RPnE, and RPwE. Alterations of the FAZ were less distinct in these groups which add to the variation reported previously.
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Anormalidades do Olho , Edema Macular , Retinose Pigmentar , Angiofluoresceinografia/métodos , Humanos , Vasos Retinianos , Retinose Pigmentar/complicações , Retinose Pigmentar/diagnóstico , Estudos Retrospectivos , Tomografia de Coerência Óptica/métodosRESUMO
BACKGROUND: Leber's hereditary optic neuropathy (LHON) has been considered a prototypical mitochondriopathy and a textbook example for maternal inheritance linked to certain disease-causing variants in the mitochondrial genome. Recently, an autosomal recessive form of LHON (arLHON) has been described, caused by disease-causing variants in the nuclear encoded gene DNAJC30. METHODS AND RESULTS: In this study, we screened the DNAJC30 gene in a large Central European cohort of patients with a clinical diagnosis of LHON or other autosomal inherited optic atrophies (OA). We identified likely pathogenic variants in 35/1202 patients, corresponding to a detection rate of 2.9%. The previously described missense variant c.152A>G;p.(Tyr51Cys) accounts for 90% of disease-associated alleles in our cohort and we confirmed a strong founder effect. Furthermore, we identified two novel pathogenic variants in DNAJC30: the nonsense variant c.610G>T;p.(Glu204*) and the in-frame deletion c.230_232del;p.(His77del). Clinical investigation of the patients with arLHON revealed a younger age of onset, a more frequent bilateral onset and an increased clinically relevant recovery compared with LHON associated with disease-causing variants in the mitochondrial DNA. CONCLUSION: This study expands previous findings on arLHON and emphasises the importance of DNAJC30 in the genetic diagnostics of LHON and OA in European patients.
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Proteínas de Choque Térmico HSP40 , Atrofia Óptica Hereditária de Leber , Humanos , DNA Mitocondrial/genética , Proteínas de Choque Térmico HSP40/genética , Mitocôndrias/genética , Atrofia Óptica Hereditária de Leber/diagnóstico , Atrofia Óptica Hereditária de Leber/epidemiologia , Atrofia Óptica Hereditária de Leber/genéticaRESUMO
PURPOSE: The aim of this study is to investigate patients´ treatment preference between the pro re nata (PRN) and treat and extend (T&E) regimens and their feelings and contentment undergoing intravitreal injections (IVI) with anti-vascular endothelial growth factor (anti-VEGF) agents. METHODS: Six months after the switch of the treatment regimen from PRN to T&E, answers of a 16-item questionnaire of 105 patients under IVI therapy regarding age, sex and treatment preference (T&E or PRN regimen), as well as burden and anxiety resulting from therapy, were evaluated. Analysis of associations between answers of the questionnaire was executed using Pearson's Chi2 test and Mann-Whitney U test. P values ≤ 0.05 were considered statistically significant. RESULTS: Nearly all patients (90.5%) felt well informed about disease and therapy. Comparing treatment regimen, 13.7% thought PRN was better and 23.3% felt T&E was better. The majority considered PRN and T&E to be equal (60.3%). No significant association between treatment regimen and age (p = 0.15), gender (p = 0.35) and duration of IVI therapy (p = 0.42) was seen. The examination results are associated with fear in the majority of patients (53.3%). Fear about the IVI was indicated by 47.6% of individuals and was significantly associated with pain during treatment (p = 0.0003), pain after treatment (p = 0.004) and fear about unfavourable examination results regarding disease activity (p = 7.94 × 10-7). CONCLUSIONS: Most patients are satisfied with the IVI therapy and the treatment regimen. Fear of the IVI and particularly of unfavourable examination results demonstrate the high treatment burden for patients undergoing anti-VEGF therapy. These aspects should be taken into account by healthcare professionals.
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Inibidores da Angiogênese , Ranibizumab , Seguimentos , Humanos , Injeções Intravítreas , Estudos Retrospectivos , Tomografia de Coerência Óptica , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular , Acuidade VisualRESUMO
Autosomal dominant optic atrophy is one of the most common inherited optic neuropathies. This disease is genetically heterogeneous, but most cases are due to pathogenic variants in the OPA1 gene: depending on the population studied, 32-90% of cases harbor pathogenic variants in this gene. The aim of this study was to provide a comprehensive overview of the entire spectrum of likely pathogenic variants in the OPA1 gene in a large cohort of patients. Over a period of 20 years, 755 unrelated probands with a diagnosis of bilateral optic atrophy were referred to our laboratory for molecular genetic investigation. Genetic testing of the OPA1 gene was initially performed by a combined analysis using either single-strand conformation polymorphism or denaturing high performance liquid chromatography followed by Sanger sequencing to validate aberrant bands or melting profiles. The presence of copy number variations was assessed using multiplex ligation-dependent probe amplification. Since 2012, genetic testing was based on next-generation sequencing platforms. Genetic screening of the OPA1 gene revealed putatively pathogenic variants in 278 unrelated probands which represent 36.8% of the entire cohort. A total of 156 unique variants were identified, 78% of which can be considered null alleles. Variant c.2708_2711del/p.(V903Gfs*3) was found to constitute 14% of all disease-causing alleles. Special emphasis was placed on the validation of splice variants either by analyzing cDNA derived from patients´ blood samples or by heterologous splice assays using minigenes. Splicing analysis revealed different aberrant splicing events, including exon skipping, activation of exonic or intronic cryptic splice sites, and the inclusion of pseudoexons. Forty-eight variants that we identified were novel. Nine of them were classified as pathogenic, 34 as likely pathogenic and five as variant of uncertain significance. Our study adds a significant number of novel variants to the mutation spectrum of the OPA1 gene and will thereby facilitate genetic diagnostics of patients with suspected dominant optic atrophy.
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GTP Fosfo-Hidrolases/genética , Predisposição Genética para Doença , Mutação/genética , Atrofia Óptica Autossômica Dominante/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Substituição de Aminoácidos , Sequência de Bases , Criança , Estudos de Coortes , Feminino , GTP Fosfo-Hidrolases/sangue , GTP Fosfo-Hidrolases/química , Humanos , Masculino , Pessoa de Meia-Idade , Atrofia Óptica Autossômica Dominante/sangue , Adulto JovemRESUMO
BACKGROUND: Due to improvements in neonatal care of premature infants and the development of novel treatment options for retinopathy of prematurity (ROP), the requirements for screening for ROP have changed since publication of the last version of the German ROP screening guideline in 2008. Based on results of recent studies, the guideline has been extensively revised in 2020 and published in an updated version. OBJECTIVE: This article summarizes the most important changes in the new guideline. RESULTS: The age limit for screening inclusion was lowered to a gestational age of below 31 weeks for infants without additional risk factors. The minimum duration of oxygen supplementation necessitating screening inclusion in preterm infants was increased to more than 5 days. Treatment for ROP in zone II can now be given at any stage 3 with plus disease, regardless of the number of clock hours affected. Criteria for the frequency and duration have been defined for follow-up examinations after anti-vascular endothelial growth factor (VEGF) treatment. The binding document for these and other new recommendations is the guideline itself. CONCLUSION: The guideline recommendations enable a reliable identification of infants at risk for ROP for screening inclusion and a timely detection of advanced disease stages for treatment initiation, thus preventing blindness from ROP.
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Retinopatia da Prematuridade , Inibidores da Angiogênese/uso terapêutico , Bevacizumab/uso terapêutico , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Injeções Intravítreas , Fotocoagulação a Laser , Retinopatia da Prematuridade/diagnóstico , Retinopatia da Prematuridade/epidemiologia , Fator A de Crescimento do Endotélio VascularRESUMO
Biallelic mutations in ACO2, encoding the mitochondrial aconitase 2, have been identified in individuals with neurodegenerative syndromes, including infantile cerebellar retinal degeneration and recessive optic neuropathies (locus OPA9). By screening European cohorts of individuals with genetically unsolved inherited optic neuropathies, we identified 61 cases harbouring variants in ACO2, among whom 50 carried dominant mutations, emphasizing for the first time the important contribution of ACO2 monoallelic pathogenic variants to dominant optic atrophy. Analysis of the ophthalmological and clinical data revealed that recessive cases are affected more severely than dominant cases, while not significantly earlier. In addition, 27% of the recessive cases and 11% of the dominant cases manifested with extraocular features in addition to optic atrophy. In silico analyses of ACO2 variants predicted their deleterious impacts on ACO2 biophysical properties. Skin derived fibroblasts from patients harbouring dominant and recessive ACO2 mutations revealed a reduction of ACO2 abundance and enzymatic activity, and the impairment of the mitochondrial respiration using citrate and pyruvate as substrates, while the addition of other Krebs cycle intermediates restored a normal respiration, suggesting a possible short-cut adaptation of the tricarboxylic citric acid cycle. Analysis of the mitochondrial genome abundance disclosed a significant reduction of the mitochondrial DNA amount in all ACO2 fibroblasts. Overall, our data position ACO2 as the third most frequently mutated gene in autosomal inherited optic neuropathies, after OPA1 and WFS1, and emphasize the crucial involvement of the first steps of the Krebs cycle in the maintenance and survival of retinal ganglion cells.
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We present a long-term follow-up in autosomal dominant gyrate atrophy-like choroidal dystrophy (adGALCD) and propose a possible genotype/phenotype correlation. Ophthalmic examination of six patients from two families revealed confluent areas of choroidal atrophy resembling gyrate atrophy, starting in the second decade of life. Progression continued centrally, reaching the fovea at about 60 years of age. Subretinal deposits, retinal pigmentation or choroidal neovascularization as seen in late-onset retinal degeneration (LORD) were not observed. Whole genome sequencing revealed a novel missense variant in the C1QTNF5 gene (p.(Q180E)) which was found in heterozygous state in all affected subjects. Haplotype analysis showed that this variant found in both families is identical by descent. Three-dimensional modeling of the possible supramolecular assemblies of C1QTNF5 revealed that the p.(Q180E) variant led to the destabilization of protein tertiary and quaternary structures, affecting both the stability of the single protomer and the entire globular head, thus exerting detrimental effects on the formation of C1QTNF5 trimeric globular domains and their interaction. In conclusion, we propose that the p.(Q180E) variant causes a specific phenotype, adGALCD, that differs in multiple clinical aspects from LORD. Disruption of optimal cell-adhesion mechanisms is expected when analyzing the effects of the point mutation at the protein level.