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ESRETNET Study Group, The ERDC Study Group, The Associated Clinical Study Group., Inherited retinal diseases (IRDs), defined by dysfunction or progressive loss of photoreceptors, are disorders characterized by elevated heterogeneity, both at the clinical and genetic levels. Our main goal was to address the genetic landscape of IRD in the largest cohort of Spanish patients reported to date. A retrospective hospital-based cross-sectional study was carried out on 6089 IRD affected individuals (from 4403 unrelated families), referred for genetic testing from all the Spanish autonomous communities. Clinical, demographic and familiar data were collected from each patient, including family pedigree, age of appearance of visual symptoms, presence of any systemic findings and geographical origin. Genetic studies were performed to the 3951 families with available DNA using different molecular techniques. Overall, 53.2% (2100/3951) of the studied families were genetically characterized, and 1549 different likely causative variants in 142 genes were identified. The most common phenotype encountered is retinitis pigmentosa (RP) (55.6% of families, 2447/4403). The most recurrently mutated genes were PRPH2, ABCA4 and RS1 in autosomal dominant (AD), autosomal recessive (AR) and X-linked (XL) NON-RP cases, respectively; RHO, USH2A and RPGR in AD, AR and XL for non-syndromic RP; and USH2A and MYO7A in syndromic IRD. Pathogenic variants c.3386G > T (p.Arg1129Leu) in ABCA4 and c.2276G > T (p.Cys759Phe) in USH2A were the most frequent variants identified. Our study provides the general landscape for IRD in Spain, reporting the largest cohort ever presented. Our results have important implications for genetic diagnosis, counselling and new therapeutic strategies to both the Spanish population and other related populations., This work was supported by the Instituto de Salud Carlos III (ISCIII) of the Spanish Ministry of Health (FIS; PI16/00425 and PI19/00321), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER, 06/07/0036), IIS-FJD BioBank (PT13/0010/0012), Comunidad de Madrid (CAM, RAREGenomics Project, B2017/BMD-3721), European Regional Development Fund (FEDER), the Organización Nacional de Ciegos Españoles (ONCE), Fundación Ramón Areces, Fundación Conchita Rábago and the University Chair UAM-IIS-FJD of Genomic Medicine. Irene Perea-Romero is supported by a PhD fellowship from the predoctoral Program from ISCIII (FI17/00192). Ionut F. Iancu is supported by a grant from the Comunidad de Madrid (CAM, PEJ-2017-AI/BMD7256). Marta del Pozo-Valero is supported by a PhD grant from the Fundación Conchita Rábago. Berta Almoguera is supported by a Juan Rodes program from ISCIII (JR17/00020). Pablo Minguez is supported by a Miguel Servet program from ISCIII (CP16/00116). Marta Corton is supported by a Miguel Servet program from ISCIII (CPII17/00006).

Spinocerebellar Ataxia 23 (SCAR23) is a newly described condition caused by mutations in TDP2 gene. To date, only four patients from two families have been reported, all carrying the same homozygous mutation. We describe a fifth patient, carrying a novel mutation in the same gene, thus confirming the role of TDP2 mutations in determining the disease and defining the main features SCAR23: pediatric onset ataxia and drug-resistant epilepsy and intellectual disability. We further show the clinical presentation which is associated with the neuroradiological evidence of progressive cerebellar atrophy, giving the evidence that SCAR23 can be classified as a degenerative condition.

In this paper, we describe QUBIC, an experiment that will observe the polarized microwave sky with a novel approach, which combines the sensitivity of state-of-the-art bolometric detectors with the systematic effects control typical of interferometers. QUBIC’s unique features are the so-called “self-calibration”, a technique that allows us to clean the measured data from instrumental effects, and its spectral imaging power, i.e., the ability to separate the signal into various sub-bands within each frequency band. QUBIC will observe the sky in two main frequency bands: 150 GHz and 220 GHz. A technological demonstrator is currently under testing and will be deployed in Argentina during 2019, while the final instrument is expected to be installed during 2020., La lista completa de autores que integran el documento puede consultarse en el archivo., Facultad de Ciencias Astronómicas y Geofísicas

BACKGROUND: Inherited retinal dystrophies, including Retinitis Pigmentosa and Leber Congenital Amaurosis among others, are a group of genetically heterogeneous disorders that lead to variable degrees of visual deficits. They can be caused by mutations in over 100 genes and there is evidence for the presence of as yet unidentified genes in a significant proportion of patients. We aimed at identifying a novel gene for an autosomal recessive form of early onset severe retinal dystrophy in a patient carrying no previously described mutations in known genes. METHODS: An integrated strategy including homozygosity mapping and whole exome sequencing was used to identify the responsible mutation. Functional tests were performed in the medaka fish (Oryzias latipes) model organism to gain further insight into the pathogenic role of the ADAMTS18 gene in eye and central nervous system (CNS) dysfunction. RESULTS: This study identified, in the analyzed patient, a homozygous missense mutation in the ADAMTS18 gene, which was recently linked to Knobloch syndrome, a rare developmental disorder that affects the eye and the occipital skull. In vivo gene knockdown performed in medaka fish confirmed both that the mutation has a pathogenic role and that the inactivation of this gene has a deleterious effect on photoreceptor cell function. CONCLUSION: This study reveals that mutations in the ADAMTS18 gene can cause a broad phenotypic spectrum of eye disorders and contribute to shed further light on the complexity of retinal diseases. Background: Inherited retinal dystrophies, including Retinitis Pigmentosa and Leber Congenital Amaurosis among others, are a group of genetically heterogeneous disorders that lead to variable degrees of visual deficits. They can be caused by mutations in over 100 genes and there is evidence for the presence of as yet unidentified genes in a significant proportion of patients. We aimed at identifying a novel gene for an autosomal recessive form of early onset severe retinal dystrophy in a patient carrying no previously described mutations in known genes.Methods: An integrated strategy including homozygosity mapping and whole exome sequencing was used to identify the responsible mutation. Functional tests were performed in the medaka fish (Oryzias latipes) model organism to gain further insight into the pathogenic role of the ADAMTS18 gene in eye and central nervous system (CNS) dysfunction.Results: This study identified, in the analyzed patient, a homozygous missense mutation in the ADAMTS18 gene, which was recently linked to Knobloch syndrome, a rare developmental disorder that affects the eye and the occipital skull. In vivo gene knockdown performed in medaka fish confirmed both that the mutation has a pathogenic role and that the inactivation of this gene has a deleterious effect on photoreceptor cell function.Conclusion: This study reveals that mutations in the ADAMTS18 gene can cause a broad phenotypic spectrum of eye disorders and contribute to shed further light on the complexity of retinal diseases.

OBJECTIVE: To investigate the involvement of the Bardet-Biedl syndrome (BBS) gene BBS1 p.M390R variant in nonsyndromic autosomal recessive retinitis pigmentosa (RP). METHODS: Homozygosity mapping of a patient with isolated RP was followed by BBS1 sequence analysis. We performed restriction fragment length polymorphism analysis of the p.M390R allele in 2007 patients with isolated RP or autosomal recessive RP and in 1824 ethnically matched controls. Patients with 2 BBS1 variants underwent extensive clinical and ophthalmologic assessment. RESULTS: In an RP proband who did not fulfill the clinical criteria for BBS, we identified a large homozygous region encompassing the BBS1 gene, which carried the p.M390R variant. In addition, this variant was detected homozygously in 10 RP patients and 1 control, compound heterozygously in 3 patients, and heterozygously in 5 patients and 6 controls. The 14 patients with 2 BBS1 variants showed the entire clinical spectrum, from nonsyndromic RP to full-blown BBS. In 8 of 14 patients, visual acuity was significantly reduced. In patients with electroretinographic responses, a rod-cone pattern of photoreceptor degeneration was observed. CONCLUSIONS: Variants in BBS1 are significantly associated with nonsyndromic autosomal recessive RP and relatively mild forms of BBS. As exemplified in this study by the identification of a homozygous p.M390R variant in a control individual and in unaffected parents of BBS patients in other studies, cis - or trans -acting modifiers may influence the disease phenotype. CLINICAL RELEVANCE: It is important to monitor patients with an early diagnosis of mild BBS phenotypes for possible life-threatening conditions.

Objective: This study was undertaken to assess the impact of immunosuppressive and immunomodulatory therapies on the severity of coronavirus disease 2019 (COVID-19) in people with multiple sclerosis (PwMS). Methods: We retrospectively collected data of PwMS with suspected or confirmed COVID-19. All the patients had complete follow-up to death or recovery. Severe COVID-19 was defined by a 3-level variable: mild disease not requiring hospitalization versus pneumonia or hospitalization versus intensive care unit (ICU) admission or death. We evaluated baseline characteristics and MS therapies associated with severe COVID-19 by multivariate and propensity score (PS)-weighted ordinal logistic models. Sensitivity analyses were run to confirm the results. Results: Of 844 PwMS with suspected (n = 565) or confirmed (n = 279) COVID-19, 13 (1.54%) died; 11 of them were in a progressive MS phase, and 8 were without any therapy. Thirty-eight (4.5%) were admitted to an ICU; 99 (11.7%) had radiologically documented pneumonia; 96 (11.4%) were hospitalized. After adjusting for region, age, sex, progressive MS course, Expanded Disability Status Scale, disease duration, body mass index, comorbidities, and recent methylprednisolone use, therapy with an anti-CD20 agent (ocrelizumab or rituximab) was significantly associated (odds ratio [OR] = 2.37, 95% confidence interval [CI] = 1.18–4.74, p = 0.015) with increased risk of severe COVID-19. Recent use (

Correction: A MT-TL1 variant identified by whole exome sequencing in an individual with intellectual disability, epilepsy, and spastic tetraparesis. Eur J Hum Genet. 2021 Sep;29(9):1470-1471. doi: 10.1038/s41431-021-00937-3. The genetic etiology of intellectual disability remains elusive in almost half of all affected individuals. Within the Solve-RD consortium, systematic re-analysis of whole exome sequencing (WES) data from unresolved cases with (syndromic) intellectual disability (n = 1,472 probands) was performed. This re-analysis included variant calling of mitochondrial DNA (mtDNA) variants, although mtDNA is not specifically targeted in WES. We identified a functionally relevant mtDNA variant in MT-TL1 (NC_012920.1:m.3291T > C; NC_012920.1:n.62T > C), at a heteroplasmy level of 22% in whole blood, in a 23-year-old male with severe intellectual disability, epilepsy, episodic headaches with emesis, spastic tetraparesis, brain abnormalities, and feeding difficulties. Targeted validation in blood and urine supported pathogenicity, with heteroplasmy levels of 23% and 58% in index, and 4% and 17% in mother, respectively. Interestingly, not all phenotypic features observed in the index have been previously linked to this MT-TL1 variant, suggesting either broadening of the m.3291T > C-associated phenotype, or presence of a co-occurring disorder. Hence, our case highlights the importance of underappreciated mtDNA variants identifiable from WES data, especially for cases with atypical mitochondrial phenotypes and their relatives in the maternal line. This work was financially supported by Aspasia grants of the Dutch Research Council (015.014.036 to TK and 015.014.066 to LELMV), the European Research Council (ERC to RH), the Well come Investigator Award (109915/Z/15/Z to RH), the Medical Research Council UK (MR/N025431/1 to RH), the Newton Fund (MR/N027302/1 to RH), the Lily Foundation (RH), and the Evelyn Trust (RH). The Solve-RD project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 779257. Sí

Background This research aimed to establish recommendations on the clinical and genetic characteristics necessary to confirm patient eligibility for gene supplementation with voretigene neparvovec. Methods An expert steering committee comprising an interdisciplinary panel of Italian experts in the three fields of medical specialisation involved in the management of RPE65-associated inherited retinal disease (IRD) (medical retina, genetics, vitreoretinal surgery) proposed clinical questions necessary to determine the correct identification of patients with the disease, determine the fundamental clinical and genetics tests to reach the correct diagnosis and to evaluate the urgency to treat patients eligible to receive treatment with voretigene neparvovec. Supported by an extensive review of the literature, a series of statements were developed and refined to prepare precisely constructed questionnaires that were circulated among an external panel of experts comprising ophthalmologists (retina specialists, vitreoretinal surgeons) and geneticists with extensive experience in IRDs in Italy in a two-round Delphi process. Results The categories addressed in the questionnaires included clinical manifestations of RPE65-related IRD, IRD screening and diagnosis, gene testing and genotyping, ocular gene therapy for IRDs, patient eligibility and prioritisation and surgical issues. Response rates by the survey participants were over 90% for the majority of items in both Delphi rounds. The steering committee developed the key consensus recommendations on each category that came from the two Delphi rounds into a simple and linear diagnostic algorithm designed to illustrate the patient pathway leading from the patient’s referral centre to the retinal specialist centre. Conclusions Consensus guidelines were developed to guide paediatricians and general ophthalmologists to arrive at the correct diagnosis of RPE65-associated IRD and make informed clinical decisions regarding eligibility for a gene therapy approach to RPE65-associated IRD. The guidelines aim to ensure the best outcome for the patient, based on expert opinion, the published literature, and practical experience in the field of IRDs.

Rare genetic neurological disorders (RND; ORPHA:71859) are a heterogeneous group of disorders comprising >1700 distinct genetic disease entities. However, genetic discoveries have not yet translated into dramatic increases of diagnostic yield and indeed rates of molecular genetic diagnoses have been stuck at about 30–50% across NGS modalities and RND phenotypes [1, 2]. Existence of yet unknown disease genes as well as shortcomings of commonly employed NGS technologies and analysis pipelines in detecting certain variant types are typically cited to explain the low diagnosis rates. To increase the diagnostic yield in RNDs - one of the four focus disease groups in Solve-RD - we follow two major approaches, that we will here present and exemplify: (i) systematic state-of the art re-analysis of large cohorts of unsolved whole-exome/genome sequencing (WES/WGS) RND datasets; and (ii) novel-omics approaches. Based on the way Solve-RD systematically organizes researchers’ expertise to channel this approach [3], the European Reference Network for Rare Neurological Diseases (ERN-RND) has established its own Data Interpretation Task Force (DITF) within SOLVE-RD, which is currently composed of clinical and genetic experts from 29 sites in 15 European countries. The Solve-RD project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 779257. Data were analysed using the RD‐Connect Genome‐Phenome Analysis Platform, which received funding from EU projects RD‐Connect, Solve-RD and EJP-RD (Grant Numbers FP7 305444, H2020 779257, H2020 825575), Instituto de Salud Carlos III (Grant Numbers PT13/0001/0044, PT17/0009/0019; Instituto Nacional de Bioinformática, INB) and ELIXIR Implementation Studies. The study was further funded by the Federal Ministry of Education and Research, Germany, through the TreatHSP network (01GM1905 to RS and LS), the National Institute of Neurological Diseases and Stroke (R01NS072248 to SZ and RS), the European Joint Program on Rare Diseases-EJP-RD COFUND-EJP N° 825575 through funding for the PROSPAX consortium (441409627 to MS, RS and BvW). CW was supported by the PATE program of the Medical Faculty, University of Tübingen. CEE received support from the Dutch Princess Beatrix Muscle Fund and the Dutch Spieren voor Spieren Muscle fund. Authors on this paper are members of the European Reference Network for Rare Neurological Diseases (ERN-RND, Project ID 739510)

Purpose: To present visual outcomes of the first two Italian patients with RPE65-related inherited retinal dystrophy (RPE65-IRD) treated with voretigene neparvovec (VN). Methods: Two pediatric patients with RPE65-IRD were treated with VN in both eyes. Patients were evaluated by best-corrected visual acuity (BCVA), full-field stimulus threshold (FST) test, semiautomated kinetic visual field (SKVF), microperimetry, and chromatic pupillometry over 6 months. Results: No complications occurred in the first patient, whereas in the second a subreti-nal hemorrhage was observed in the first treated eye, and excessive resistance to drug injection occurred during treatment of the second eye. BCVA improved by at least one Early Treatment Diabetic Retinopathy Study line in all treated eyes. The FST test and SKVF showed clinically significant improvements in all eyes (i.e., change of light sensitivity > 10 decibels; area enlargement of at least 20%). Moreover, microperimetry showed better fixation stability. Finally, chromatic pupillometry showed increases in pupillary constric-tion that ranged from 10% to 20%. All visual changes remained stable during follow-up. Conclusions: The first VN treatments in two pediatric Italian patients in clinical practice showed significant improvements in visual outcomes, even in the case of surgical complications, which spontaneously recovered without sequelae. Translational Relevance: These findings with VN in patients with RPE65-IRD confirm the results of clinical trials.

PURPOSE. The purpose of this study was to perform a detailed longitudinal phenotyping and genetic characterization of 32 Italian patients with a nonsyndromic retinal dystrophy and mutations in the CEP290 gene. METHODS. We reviewed the clinical history and examinations of 32 patients with a nonsyndromic retinal dystrophy due to mutations in the CEP290 gene, followed up (mean followup: 5.9 years) at 3 Italian centers. The clinical examinations included: best corrected visual acuity (BCVA), optical coherence tomography (OCT), and full-field electroretinogram (ERG). RESULTS. Patients (mean age = 19.0 ± 3.4 years) had a mean BCVA of 1.73 ± 0.20 logMAR. Longitudinal analysis of BCVA showed a nonsignificant decline. Central retinal thickness (CRT) declined significantly with age at an exponential rate of 1.0%/year (P = 0.001). At disease onset, most patients (19/32; 49.4%) had nystagmus. The absence of nystagmus was significantly associated with better BCVA and more preserved CRT (P < 0.05). ERG showed undetectable responses in most patients (64.0%), whereas reduced scotopic and photopic responses were observed in four patients (16.0%) who had no nystagmus. We identified 35 different variants, among which 12 were novel. Our genotype-phenotype correlation analysis shows a significantly worse BCVA in patients harboring a loss-of-function mutation and the deep-intronic variant c.2991+1655A>G. CONCLUSIONS. Our study highlights a mild phenotype of the disease, characterized by absence of nystagmus, good visual acuity, considerably preserved retinal morphology, and recordable ERG, confirming the wide spectrum of CEP290-related retinal dystrophies. Finally, in our cohort, the deep intronic variant c.2991+1655A>G was associated with a more severe phenotype.

Biallelic loss of function of TELO2 gene cause a severe syndromic disease mainly characterized by global developmental delay with poor motor and language acquisitions, microcephaly, short stature, minor facial and limbs anomalies, sleep disorder, spasticity, and balance impairment up to ataxia. TELO2-related syndrome, also known as You-Hoover-Fong Syndrome, is extremely rare and since its first description in 2016 only 8 individuals have been reported, all showing a severe disability. The causative gene is member of the big molecular family of genes responsible for cells proliferation and DNA stability. We describe the case of two sisters, carrying the homozygous p. Arg609His variant of the gene, who present a milder phenotype of TELO2-related syndrome. Such variant has been reported once in a more severely affected patient, in compound heterozygous state associated with the p. Pro260Leu variant, suggesting a possible role of the p. Arg609His variant in determining milder phenotypes. Comparing the siblings with all previously reported cases, we offer an overview on the condition and discuss TELO2 genetic interactions, in order to further explore the molecular bases of this recently described disorder.

Correction to: Solving patients with rare diseases through programmatic reanalysis of genome-phenome data. Eur J Hum Genet. 2021 Sep;29(9):1466-1469. doi: 10.1038/s41431-021-00934-6. PMID: 34393220 Reanalysis of inconclusive exome/genome sequencing data increases the diagnosis yield of patients with rare diseases. However, the cost and efforts required for reanalysis prevent its routine implementation in research and clinical environments. The Solve-RD project aims to reveal the molecular causes underlying undiagnosed rare diseases. One of the goals is to implement innovative approaches to reanalyse the exomes and genomes from thousands of well-studied undiagnosed cases. The raw genomic data is submitted to Solve-RD through the RD-Connect Genome-Phenome Analysis Platform (GPAP) together with standardised phenotypic and pedigree data. We have developed a programmatic workflow to reanalyse genome-phenome data. It uses the RD-Connect GPAP's Application Programming Interface (API) and relies on the big-data technologies upon which the system is built. We have applied the workflow to prioritise rare known pathogenic variants from 4411 undiagnosed cases. The queries returned an average of 1.45 variants per case, which first were evaluated in bulk by a panel of disease experts and afterwards specifically by the submitter of each case. A total of 120 index cases (21.2% of prioritised cases, 2.7% of all exome/genome-negative samples) have already been solved, with others being under investigation. The implementation of solutions as the one described here provide the technical framework to enable periodic case-level data re-evaluation in clinical settings, as recommended by the American College of Medical Genetics. The Solve-RD project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 779257. Data were analysed using the RD‐Connect Genome‐Phenome Analysis Platform, which received funding from EU projects RD‐Connect, Solve-RD and EJP-RD (grant numbers FP7 305444, H2020 779257, H2020 825575), Instituto de Salud Carlos III (grant numbers PT13/0001/0044, PT17/0009/0019; Instituto Nacional de Bioinformática, INB) and ELIXIR Implementation Studies. We acknowledge support of the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) to the EMBL partnership, the Centro de Excelencia Severo Ochoa and the CERCA Programme/Generalitat de Catalunya. We also acknowledge the support of the Generalitat de Catalunya through Departament de Salut and Departament d’Empresa i Coneixement and the Co-financing by the Spanish Ministry of Economy, Industry and Competitiveness (MEIC) with funds from the European Regional Development Fund (ERDF) corresponding to the 2014-2020 Smart Growth Operating Program. Sí

Pathogenic variants in the MKS1 gene are responsible for a ciliopathy with a wide spectrum of clinical manifestations ranging from Meckel and Joubert syndrome (JBTS) to Bardet-Biedl syndrome, and involving the central nervous system, liver, kidney, skeleton, and retina. We report a 39-year-old male individual presenting with isolated Retinitis Pigmentosa (RP), as assessed by full ophthalmological evaluation including Best-Corrected Visual Acuity measurements, fundus examination, Goldmann Visual Field test, and full-field Electroretinography. A clinical exome identified biallelic nonsense variants in MKS1 that prompted post-genotyping investigations for systemic abnormalities of ciliopathy. Brain magnetic resonance imaging revealed malformations of the posterior cranial fossa with the ‘molar tooth sign’ and cerebellar folia dysplasia, which are both distinctive features of JBTS. No other organ or skeletal abnormalities were detected. This case illustrates the power of clinical exome for the identification of the mildest forms of a disease spectrum, such as a mild JBTS with RP in the presented case of an individual carrying biallelic truncating variants in MKS1.

Achromatopsia (ACHM) is a rare genetic disorder of infantile onset affecting cone photoreceptors. To determine the extent of progressive retinal changes in achromatopsia, we performed a detailed longitudinal phenotyping and genetic characterization of an Italian cohort comprising 21 ACHM patients (17 unrelated families). Molecular genetic testing identified biallelic pathogenic mutations in known ACHM genes, including four novel variants. At baseline, the patients presented a reduced best corrected visual acuity (BCVA), reduced macular sensitivity (MS), normal dark-adapted electroretinogram (ERG) responses and undetectable or severely reduced light-adapted ERG. The longitudinal analysis of 16 patients (mean follow-up: 5.4 ± 1.0 years) showed a significant decline of BCVA (0.012 logMAR/year) and MS (−0.16 dB/year). Light-adapted and flicker ERG responses decreased below noise level in three and two patients, respectively. Only two patients (12.5%) progressed to a worst OCT grading during the follow-up. Our findings corroborate the notion that ACHM is a progressive disease in terms of BCVA, MS and ERG responses, and affects slowly the structural integrity of the retina. These observations can serve towards the development of guidelines for patient selection and intervention timing in forthcoming gene replacement therapies.

Gene therapy is proving to be an effective approach to treat or prevent ocular diseases ensuring a targeted, stable, and regulated introduction of exogenous genetic material with therapeutic action. Retinal diseases can be broadly categorized into two groups, namely monogenic and complex (multifactorial) forms. The high genetic heterogeneity of monogenic forms represents a significant limitation to the application of gene-specific therapeutic strategies for a significant fraction of patients. Therefore, mutation-independent therapeutic strategies, acting on common pathways that underly retinal damage, are gaining interest as complementary/alternative approaches for retinal diseases. This review will provide an overview of mutation-independent strategies that rely on the modulation in the retina of key genes regulating such crucial degenerative pathways. In particular, we will describe how gene-based approaches explore the use of neurotrophic factors, microRNAs (miRNAs), genome editing and optogenetics in order to restore/prolong visual function in both outer and inner retinal diseases. We predict that the exploitation of gene delivery procedures applied to mutation/gene independent approaches may provide the answer to the unmet therapeutic need of a large fraction of patients with genetically heterogeneous and complex retinal diseases.

International audience; Purpose: Nontruncating variants in SMARCA2, encoding a catalytic subunit of SWI/SNF chromatin remodeling complex, cause Nicolaides-Baraitser syndrome (NCBRS), a condition with intellectual disability and multiple congenital anomalies. Other disorders due to SMARCA2 are unknown.Methods: By next-generation sequencing, we identified candidate variants in SMARCA2 in 20 individuals from 18 families with a syndromic neurodevelopmental disorder not consistent with NCBRS. To stratify variant interpretation, we functionally analyzed SMARCA2 variants in yeasts and performed transcriptomic and genome methylation analyses on blood leukocytes.Results: Of 20 individuals, 14 showed a recognizable phenotype with recurrent features including epicanthal folds, blepharophimosis, and downturned nasal tip along with variable degree of intellectual disability (or blepharophimosis intellectual disability syndrome [BIS]). In contrast to most NCBRS variants, all SMARCA2 variants associated with BIS are localized outside the helicase domains. Yeast phenotype assays differentiated NCBRS from non-NCBRS SMARCA2 variants. Transcriptomic and DNA methylation signatures differentiated NCBRS from BIS and those with nonspecific phenotype. In the remaining six individuals with nonspecific dysmorphic features, clinical and molecular data did not permit variant reclassification.Conclusion: We identified a novel recognizable syndrome named BIS associated with clustered de novo SMARCA2 variants outside the helicase domains, phenotypically and molecularly distinct from NCBRS.

MicroRNAs (miRNAs) are small noncoding RNAs playing a fundamental role in the regulation of gene expression. Evidence accumulating in the past decades indicate that they are capable of simultaneously modulating diverse signaling pathways involved in a variety of pathophysiological processes. In the present review, we provide a comprehensive overview of the function of a highly conserved group of miRNAs, the miR-181 family, both in physiological as well as in pathological conditions. We summarize a large body of studies highlighting a role for this miRNA family in the regulation of key biological processes such as embryonic development, cell proliferation, apoptosis, autophagy, mitochondrial function, and immune response. Importantly, members of this family have been involved in many pathological processes underlying the most common neurodegenerative disorders as well as different solid tumors and hematological malignancies. The relevance of this miRNA family in the pathogenesis of these disorders and their possible influence on the severity of their manifestations will be discussed. A better understanding of the miR-181 family in pathological conditions may open new therapeutic avenues for devasting disorders such as neurodegenerative diseases and cancer.

We investigated the genetic origin of the phenotype displayed by three children from two unrelated Italian families, presenting with a previously unrecognized autosomal recessive disorder that included a severe form of spondylo-epiphyseal dysplasia, sensorineural hearing loss, intellectual disability and Leber congenital amaurosis (SHILCA), as well as some brain anomalies that were visible at the MRI. Autozygome-based analysis showed that these children shared a 4.76 Mb region of homozygosity on chromosome 1, with an identical haplotype. Nonetheless, whole-exome sequencing failed to identify any shared rare coding variants, in this region or elsewhere. We then determined the transcriptome of patients’ fibroblasts by RNA sequencing, followed by additional whole-genome sequencing experiments. Gene expression analysis revealed a 4-fold downregulation of the gene NMNAT1, residing indeed in the shared autozygous interval. Short- and long-read whole-genome sequencing highlighted a duplication involving 2 out of the 5 exons of NMNAT1 main isoform (NM_022787.3), leading to the production of aberrant mRNAs. Pathogenic variants in NMNAT1 have been previously shown to cause non-syndromic Leber congenital amaurosis (LCA). However, no patient with null biallelic mutations has ever been described, and murine Nmnat1 knockouts show embryonic lethality, indicating that complete absence of NMNAT1 activity is probably not compatible with life. The rearrangement found in our cases, presumably causing a strong but not complete reduction of enzymatic activity, may therefore result in an intermediate syndromic phenotype with respect to LCA and lethality.

Retinitis pigmentosa (RP) is a clinically heterogenous disease that comprises a wide range of phenotypic and genetic subtypes. Pericentral RP is an atypical form of RP characterized by bone-spicule pigmentation and/or atrophy confined in the near mid-periphery of the retina. In contrast to classic RP, the far periphery is better preserved in pericentral RP. The aim of this study was to perform the first detailed clinical and genetic analysis of a cohort of European subjects with pericentral RP to determine the phenotypic features and the genetic bases of the disease. A total of 54 subjects from 48 independent families with pericentral RP, non-syndromic and syndromic, were evaluated through a full ophthalmological examination and underwent clinical exome or retinopathy gene panel sequencing. Disease-causative variants were identified in 22 of the 35 families (63%) in 10 different genes, four of which are also responsible for syndromic RP. Thirteen of the 34 likely pathogenic variants were novel. Intra-familiar variability was also observed. The current study confirms the mild phenotype of pericentral RP and extends the spectrum of genes associated with this condition. Retinitis pigmentosa (RP) is a clinically heterogenous disease that comprises a wide range of phenotypic and genetic subtypes. Pericentral RP is an atypical form of RP characterized by bone-spicule pigmentation and/or atrophy confined in the near mid-periphery of the retina. In contrast to classic RP, the far periphery is better preserved in pericentral RP. The aim of this study was to perform the first detailed clinical and genetic analysis of a cohort of European subjects with pericentral RP to determine the phenotypic features and the genetic bases of the disease. A total of 54 subjects from 48 independent families with pericentral RP, non-syndromic and syndromic, were evaluated through a full ophthalmological examination and underwent clinical exome or retinopathy gene panel sequencing. Disease-causative variants were identified in 22 of the 35 families (63%) in 10 different genes, four of which are also responsible for syndromic RP. Thirteen of the 34 likely pathogenic variants were novel. Intra-familiar variability was also observed. The current study confirms the mild phenotype of pericentral RP and extends the spectrum of genes associated with this condition.

Background Coffin–Siris syndrome (CSS) is characterized by intellectual disability, dysmorphic facial features, growth deficiency, microcephaly, and abnormalities of the fifth fingers/toes. CSS is caused by mutations in several genes of the BRG1‐associated factor pathway including SMARCA4. Methods Whole‐exome sequencing was performed on a 14‐year‐old female individual who presented with mild intellectual disability and dysmorphic features, tooth abnormalities, and short stature. She had brachydactyly but no aplasia or hypoplasia of the distal phalanx or nail of the fifth digit. She was also found to have retinal dystrophy that has not been previously reported in CSS. Results The individual presented herein was found to harbor a previously unreported de novo variant in SMARCA4. Conclusion This case expands the phenotypic spectrum of CSS manifestations.

Inherited retinal diseases (IRDs) represent a frequent cause of genetic blindness. Their high genetic heterogeneity hinders the application of gene-specific therapies to the vast majority of patients. We recently demonstrated that the microRNA miR-204 is essential for retinal function, although the underlying molecular mechanisms remain poorly understood. Here, we investigated the therapeutic potential of miR-204 in IRDs. We subretinally delivered an adeno-associated viral (AAV) vector carrying the miR-204 precursor to two genetically different IRD mouse models. The administration of AAV-miR-204 preserved retinal function in a mouse model for a dominant form of retinitis pigmentosa (RHO-P347S). This was associated with a reduction of apoptotic photoreceptor cells and with a better preservation of photoreceptor marker expression. Transcriptome analysis showed that miR-204 shifts expression profiles of transgenic retinas toward those of healthy retinas by the downregulation of microglia activation and photoreceptor cell death. Delivery of miR-204 exerted neuroprotective effects also in a mouse model of Leber congenital amaurosis, due to mutations of the Aipl1 gene. Our study highlights the mutation-independent therapeutic potential of AAV-miR204 in slowing down retinal degeneration in IRDs and unveils the previously unreported role of this miRNA in attenuating microglia activation and photoreceptor cell death.

We identified a 14q21.2 microdeletion in a 16-year-old boy with autism spectrum disorder (ASD), IQ in the lower part of normal range but high-functioning memory skills. The deletion affects a gene desert, and the non-deletedgene closest to the microdeletion boundaries is LRFN5, which encodes a protein involved in synaptic plasticity and implicated in neuro-psychiatric disorders. LRFN5 expression was significantly decreased in the proband’s skin fibroblasts. The deleted region includes the pseudogene chr14.232.a, which is transcribed into a long non-coding RNA (lncLRFN5-10), whose levels were also significantly reduced in the proband’s fibroblasts compared to controls. Transfection of the patient’s fibroblasts with a plasmid expressing chr14.232.a significantly increased LRFN5 expression, while siRNA targeting chr14.232.a-derived lncLRFN5-10 reduced LRFN5 levels. In summary, we report on an individual with ASD carrying a microdeletion encompassing the pseudogene chr14.232.a encoding for lncLRFN5-10, which was found to affect the expression levels of the nearby, non-deleted LRFN5. This case illustrates the potential role of long non-coding RNAs in regulating expression of neighbouring genes with a functional role in ASD pathogenesis.

The autophagy-lysosomal pathway (ALP) regulates cell homeostasis and plays a crucial role in human diseases, such as lysosomal storage disorders (LSDs) and common neurodegenerative diseases. Therefore, the identification of DNA sequence variations in genes involved in this pathway and their association with human diseases would have a significant impact on health. To this aim, we developed Lysoplex, a targeted next-generation sequencing (NGS) approach, which allowed us to obtain a uniform and accurate coding sequence coverage of a comprehensive set of 891 genes involved in lysosomal, endocytic, and autophagic pathways. Lysoplex was successfully validated on 14 different types of LSDs and then used to analyze 48 mutation-unknown patients with a clinical phenotype of neuronal ceroid lipofuscinosis (NCL), a genetically heterogeneous subtype of LSD. Lysoplex allowed us to identify pathogenic mutations in 67% of patients, most of whom had been unsuccessfully analyzed by several sequencing approaches. In addition, in 3 patients, we found potential disease-causing variants in novel NCL candidate genes. We then compared the variant detection power of Lysoplex with data derived from public whole exome sequencing (WES) efforts. On average, a 50% higher number of validated amino acid changes and truncating variations per gene were identified. Overall, we identified 61 truncating sequence variations and 488 missense variations with a high probability to cause loss of function in a total of 316 genes. Interestingly, some loss-of-function variations of genes involved in the ALP pathway were found in homozygosity in the normal population, suggesting that their role is not essential. Thus, Lysoplex provided a comprehensive catalog of sequence variants in ALP genes and allows the assessment of their relevance in cell biology as well as their contribution to human disease.

OBJECTIVE: The aim of this study was to show the clinical data of long-term (3-year) follow-up of 5 patients affected by Leber congenital amaurosis type 2 (LCA2) treated with a single unilateral injection of adeno-associated virus AAV2-hRPE65v2. DESIGN: Clinical trial. PARTICIPANTS: Five LCA2 patients with RPE65 gene mutations. METHODS: After informed consent and confirmation of trial eligibility criteria, the eye with worse visual function was selected for subretinal delivery of adeno-associated virus (AAV2-hRPE65v2). Subjects were evaluated before and after surgery at designated follow-up visits (1, 2, 3, 14, 30, 60, 90, 180, 270, and 365 days, 1.5 years, and 3 years) by complete ophthalmic examination. Efficacy for each subject was monitored with best-corrected visual acuity, kinetic visual field, nystagmus testing, and pupillary light reflex. MAIN OUTCOME MEASURES: Best-corrected visual acuity, kinetic visual field, nystagmus testing, and pupillary light reflex. RESULTS: The data showed a statistically significant improvement of best-corrected visual acuity between baseline and 3 years after treatment in the treated eye (P

Foveal hypoplasia and optic nerve misrouting are developmental defects of the visual pathway and only co-occur in connection with albinism; to date, they have only been associated with defects in the melanin-biosynthesis pathway. Here, we report that these defects can occur independently of albinism in people with recessive mutations in the putative glutamine transporter gene SLC38A8. Nine different mutations were identified in seven Asian and European families. Using morpholino-mediated ablation of Slc38a8 in medaka fish, we confirmed that pigmentation is unaffected by loss of SLC38A8. Furthermore, by undertaking an association study with SNPs at the SLC38A8 locus, we showed that common variants within this gene modestly affect foveal thickness in the general population. This study reveals a melanin-independent component underpinning the development of the visual pathway that requires a functional role for SLC38A8.

MicroRNAs (miRNAs) are small noncoding RNAs that have important roles in the regulation of gene expression. The roles of individual miRNAs in controlling vertebrate eye development remain, however, largely unexplored. Here, we show that a single miRNA, miR-204, regulates multiple aspects of eye development in the medaka fish ( Oryzias latipes ). Morpholino-mediated ablation of miR-204 expression resulted in an eye phenotype characterized by microphthalmia, abnormal lens formation, and altered dorsoventral (D-V) patterning of the retina, which is associated with optic fissure coloboma. Using a variety of in vivo and in vitro approaches, we identified the transcription factor Meis2 as one of the main targets of miR-204 function. We show that, together with altered regulation of the Pax6 pathway, the abnormally elevated levels of Meis2 resulting from miR-204 inactivation are largely responsible for the observed phenotype. These data provide an example of how a specific miRNA can regulate multiple events in eye formation; at the same time, they uncover an as yet unreported function of Meis2 in the specification of D-V patterning of the retina.

Hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders characterized by progressive weakness and spasticity in the lower limbs. Spasticity may occur in isolation (''pure'' HSP) or may be accompanied by other features. Although autosomal recessive HSPs usually have clinically complex phenotypes, mutations within a few genes underlie pure forms. Recently the gene (CYP7B1) responsible for SPG5, a pure recessive HSP, has been identified. The six CYP7B1 coding exons were analysed in four Italian families. Complete clinical assessment was performed in all patients. Blood CYP7B1 mRNA levels were assessed in three patients and six controls. Brain MRI and (18)F-fluoro-deoxy-glucose positron emission tomography (PET) scan were conducted in three patients. Two novel homozygous mutations were identified. Both result in a frameshift and the introduction of a premature stop codon at the C-terminal of the protein. Patients have reduced blood CYP7B1 mRNA levels, suggesting nonsense mediated RNA decay. Although clinical assessment showed a pure form of spastic paraplegia, MRI demonstrated white matter abnormalities in three patients and PET scan revealed cerebellar hypometabolism in one. Based on the results, we report the first Italian families with SPG5 molecular characterization and describe two novel truncating mutations in CYP7B1. The recessive character, the truncating nature of the mutations, and the reduced peripheral blood CYP7B1 mRNA levels suggest that the development of the disease is associated with a loss of function. SPG5 is considered a pure form of HSP, but MRI and PET findings in our patients suggest that SPG5 phenotype may be broader than the pure presentation.

S um m a r y Leber's congenital amaurosis (LCA) is a group of inherited blinding diseases with onset during childhood. One form of the disease, LCA2, is caused by mutations in the retinal pigment epithelium-specific 65-kDa protein gene (RPE65). We investiga t ed the safety of subretinal delivery of a recombinant adeno-associated virus (AAV) carry- ing RPE65 complementary DNA (cDNA) (ClinicalTrials.gov number, NCT00516477). Three patients with LCA2 had an acceptable local and systemic adverse-event pro- file after delivery of AAV2.hRPE65v2. Each patient had a modest improvement in measures of retinal function on subjective tests of visual acuity. In one patient, an asymptomatic macular hole developed, and although the occurrence was considered to be an adverse event, the patient had some return of retinal function. Although the follow-up was very short and normal vision was not achieved, this study pro- vides the basis for further gene therapy studies in patients with LCA.

Connectivity and function of neuronal circuitry require the correct specification and growth of axons and dendrites. Here, we identify the microRNAs miR‐181a and miR‐181b as key regulators of retinal axon specification and growth. Loss of miR‐181a/b in medaka fish (Oryzias latipes) failed to consolidate amacrine cell processes into axons and delayed the growth of retinal ganglion cell (RGC) axons. These alterations were accompanied by defects in visual connectivity and function. We demonstrated that miR‐181a/b exert these actions through negative modulation of MAPK/ERK signaling that in turn leads to RhoA reduction and proper neuritogenesis in both amacrine cells and RGCs via local cytoskeletal rearrangement. Our results identify a new pathway for axon specification and growth unraveling a crucial role of miR‐181a/b in the proper establishment of visual system connectivity and function. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1252–1267, 2015

Ocular developmental disorders, including the group classified as microphthalmia, anophthalmia, and coloboma (MAC) and inherited retinal dystrophies, collectively represent leading causes of hereditary blindness. Characterized by extreme genetic and clinical heterogeneity, the separate groups share many common genetic causes, in particular relating to pathways controlling retinal and retinal pigment epithelial maintenance. To understand these shared pathways and delineate the overlap between these groups, we investigated the genetic cause of an autosomal dominantly inherited condition of retinal dystrophy and bilateral coloboma, present in varying degrees in a large, five-generation family. By linkage analysis and exome sequencing, we identified a previously undescribed heterozygous mutation, n.37C > T, in the seed region of microRNA-204 (miR-204), which segregates with the disease in all affected individuals. We demonstrated that this mutation determines significant alterations of miR-204 targeting capabilities via in vitro assays, including transcriptome analysis. In vivo injection, in medaka fish (Oryzias latipes), of the mutated miR-204 caused a phenotype consistent with that observed in the family, including photoreceptor alterations with reduced numbers of both cones and rods as a result of increased apoptosis, thereby confirming the pathogenic effect of the n.37C > T mutation. Finally, knockdown assays in medaka fish demonstrated that miR-204 is necessary for normal photoreceptor function. Overall, these data highlight the importance of miR-204 in the regulation of ocular development and maintenance and provide the first evidence, to our knowledge, of its contribution to eye disease, likely through a gain-of-function mechanism.

MicroRNAs (miRNAs) control cell cycle progression by targeting the transcripts encoding for cyclins, CDKs and CDK inhibitors, such as p27(KIP1) (p27). p27 expression is controlled by multiple transcriptional and posttranscriptional mechanisms, including translational inhibition by miR-221/222 and posttranslational regulation by the SCF(SKP2) complex. The oncosuppressor activity of miR-340 has been recently characterized in breast, colorectal and osteosarcoma tumor cells. However, the mechanisms underlying miR-340-induced cell growth arrest have not been elucidated. Here, we describe miR-340 as a novel tumor suppressor in non-small cell lung cancer (NSCLC). Starting from the observation that the growth-inhibitory and proapoptotic effects of miR-340 correlate with the accumulation of p27 in lung adenocarcinoma and glioblastoma cells, we have analyzed the functional relationship between miR-340 and p27 expression. miR-340 targets three key negative regulators of p27. The miR-340-mediated inhibition of both Pumilio family RNA-binding proteins (PUM1 and PUM2), required for the miR-221/222 interaction with the p27 3'-UTR, antagonizes the miRNA-dependent downregulation of p27. At the same time, miR-340 induces the stabilization of p27 by targeting SKP2, the key posttranslational regulator of p27. Therefore, miR-340 controls p27 at both translational and posttranslational levels. Accordingly, the inhibition of either PUM1 or SKP2 partially recapitulates the miR-340 effect on cell proliferation and apoptosis. In addition to the effect on tumor cell proliferation, miR-340 also inhibits intercellular adhesion and motility in lung cancer cells. These changes correlate with the miR-340-mediated inhibition of previously validated (MET and ROCK1) and potentially novel (RHOA and CDH1) miR-340 target transcripts. Finally, we show that in a small cohort of NSCLC patients (n=23), representative of all four stages of lung cancer, miR-340 expression inversely correlates with clinical staging, thus suggesting that miR-340 downregulation contributes to the disease progression.

Because of its favorable anatomical and immunological characteristics, the eye has been at the forefront of translational gene therapy. Dozens of promising proofs of concept have been obtained in animal models of inherited retinal degenerations (IRDs), and some of them have been relayed to the clinic. The results from the first clinical trials for a congenital form of blindness have generated great interest and have demonstrated the safety and efficacy of intraocular administrations of viral vectors in humans. However, this progress has also generated new questions and posed challenges that need to be addressed to further expand the applicability of gene therapy in the eye, including safe delivery of viral vectors to the outer retina, treatment of dominant IRDs as well as of IRDs caused by mutations in large genes, and, finally, selection of the appropriate IRDs and patients to maximize the efficacy of gene transfer. This review summarizes the strategies that are currently being exploited to overcome these challenges and drive the clinical development of retinal gene therapy.

Item does not contain fulltext Retinitis pigmentosa (RP) is the most common form of inherited retinopathy, with an approximate incidence of 1 in 3700 individuals worldwide. Mutations in the retinitis pigmentosa 1 (RP1) gene are responsible for about 5-10% cases of autosomal dominant RP. The RP1 gene is specifically expressed in the photoreceptor layers of the postnatal retina and encodes a predicted protein characterised by the presence of two doublecortin (DC) domains, known to be implicated in microtubule binding. We identified and characterised, both in human and in mouse, a novel mammalian gene, termed Retinitis Pigmentosa1-like1 (RP1L1), because of its significant sequence similarity to the RP1 gene product. The sequence homology between RP1 and RP1L1 was found to be mostly restricted to the DC domains and to the N-terminal region, including the first 350 amino acids. The RP1L1 gene was also found to be conserved in distant vertebrates, since we identified a homologue in Fugu rubripes (pufferfish). Similar to RP1, RP1L1 expression is restricted to the postnatal retina, as determined by semiquantitative reverse transcriptase-PCR and Northern analysis. The retina-specific expression and the sequence similarity to RP1 render RP1L1 a potential candidate for inherited retinal disorders.

Understanding the molecular basis of cardiomyocyte development is critical for understanding the pathogenesis of pre- and post-natal cardiac disease. MicroRNAs (miRNAs) are post-transcriptional modulators of gene expression that play an important role in many developmental processes. Here, we show that the miR-99a/let-7c cluster, mapping on human chromosome 21, is involved in the control of cardiomyogenesis by altering epigenetic factors. By perturbing miRNA expression in mouse embryonic stem cells, we find that let-7c promotes cardiomyogenesis by upregulating genes involved in mesoderm specification (T/Bra and Nodal) and cardiac differentiation (Mesp1, Nkx2.5 and Tbx5). The action of let-7c is restricted to the early phase of mesoderm formation at the expense of endoderm and its late activation redirects cells toward other mesodermal derivatives. The Polycomb complex group protein Ezh2 is a direct target of let-7c, which promotes cardiac differentiation by modifying the H3K27me3 marks from the promoters of crucial cardiac transcription factors (Nkx2.5, Mef2c, Tbx5). In contrast, miR-99a represses cardiac differentiation via the nucleosome-remodeling factor Smarca5, attenuating the Nodal/Smad2 signaling. We demonstrated that the identified targets are underexpressed in human Down syndrome fetal heart specimens. By perturbing the expression levels of these miRNAs in embryonic stem cells, we were able to demonstrate that these miRNAs control lineage- and stage-specific transcription factors, working in concert with chromatin modifiers to direct cardiomyogenesis.

Gene expression profiles can be used to infer previously unknown transcriptional regulatory interaction among thousands of genes, via systems biology 'reverse engineering' approaches. We 'reverse engineered' an embryonic stem (ES)-specific transcriptional network from 171 gene expression profiles, measured in ES cells, to identify master regulators of gene expression ('hubs'). We discovered that E130012A19Rik (E13), highly expressed in mouse ES cells as compared with differentiated cells, was a central 'hub' of the network. We demonstrated that E13 is a protein-coding gene implicated in regulating the commitment towards the different neuronal subtypes and glia cells. The overexpression and knock-down of E13 in ES cell lines, undergoing differentiation into neurons and glia cells, caused a strong up-regulation of the glutamatergic neurons marker Vglut2 and a strong down-regulation of the GABAergic neurons marker GAD65 and of the radial glia marker Blbp. We confirmed E13 expression in the cerebral cortex of adult mice and during development. By immuno-based affinity purification, we characterized protein partners of E13, involved in the Polycomb complex. Our results suggest a role of E13 in regulating the division between glutamatergic projection neurons and GABAergic interneurons and glia cells possibly by epigenetic-mediated transcriptional regulation.

Long noncoding RNAs (lncRNAs) are emerging as regulators of many basic cellular pathways. Several lncRNAs are selectively expressed in the developing retina, although little is known about their functional role in this tissue. Vax2os1 is a retina-specific lncRNA whose expression is restricted to the mouse ventral retina. Here we demonstrate that spatiotemporal misexpression of Vax2os1 determines cell cycle alterations in photoreceptor progenitor cells. In particular, the overexpression of Vax2os1 in the developing early postnatal mouse retina causes an impaired cell cycle progression of photoreceptor progenitors toward their final committed fate and a consequent delay of their differentiation processes. At later developmental stages, this perturbation is accompanied by an increase of apoptotic events in the photoreceptor cell layer, in comparison with control retinas, without affecting the proper cell layering in the adult retina. Similar results are observed in mouse photoreceptor-derived 661W cells in which Vax2os1 overexpression results in an impairment of the cell cycle progression rate and cell differentiation. Based on these results, we conclude that Vax2os1 is involved in the control of cell cycle progression of photoreceptor progenitor cells in the ventral retina. Therefore, we propose Vax2os1 as the first example of lncRNA that acts as a cell cycle regulator in the mammalian retina during development.

Retinal axon specification and growth are critically sensitive to the dosage of numerous signaling molecules and transcription factors. Subtle variations in the expression levels of key molecules may result in a variety of axonal growth anomalies. miR-181a and miR-181b are two eye-enriched microRNAs whose inactivation in medaka fish leads to alterations of the proper establishment of connectivity and function in the visual system. miR-181a/b are fundamental regulators of MAPK signaling and their role in retinal axon growth and specification is just beginning to be elucidated. Here we demonstrate that miR-181a/b are key nodes in the interplay between TGF-β and MAPK/ERK within the functional pathways that control retinal axon specification and growth. Using a variety of in vivo and in vitro approaches in medaka fish, we demonstrate that TGF-β signaling controls the miR-181/ERK regulatory network, which in turn strengthens the TGF-β-mediated regulation of RhoA degradation. Significantly, these data uncover the role of TGF-β signaling in vivo, for the first time, in defining the correct wiring and assembly of functional retina neural circuits and further highlight miR-181a/b as key factors in axon specification and growth.

Background In X-linked dilated cardiomyopathy due to dystrophin mutations which abolish the expression of the M isoform (5'-XLDC), the skeletal muscle is spared through the up-regulation of the Brain (B) isoform, a compensatory mechanism that does not appear to occur in the heart of affected individuals. Methods We quantitatively studied the expression topography of both B and M isoforms in various human heart regions through in-situ RNA hybridization, Reverse-Transcriptase and Real-Time PCR experiments. We also investigated the methylation profile of the B promoter region in the heart and quantified the B isoform up regulation in the skeletal muscle of two 5'-XLDC patients. Results Unlike the M isoform, consistently detectable in all the heart regions, the B isoform was selectively expressed in atrial cardiomyocytes, but absent in ventricles and in conduction system structures. Although the level of B isoform messenger in the skeletal muscle of 5'-XLDC patients was lower that of the M messenger present in control muscle, it seems sufficient to avoid an overt muscle pathology. This result is consistent with the protein level in XLDC patients muscles we previously quantified. Methylation studies revealed that the B promoter shows an overall low level of methylation at the CG dinucleotides in both atria and ventricles, suggesting a methylation-independent regulation of the B promoter activity. Conclusions The ventricular dilatation seen in 5'-XLDC patients appears to be functionally related to loss of the M isoform, the only isoform transcribed in human ventricles; in contrast, the B isoform is well expressed in heart but confined to the atria. Since the B isoform can functionally replace the M isoform in the skeletal muscle, its expression in the heart could potentially exert the same rescue function. Methylation status does not seem to play a role in the differential B promoter activity in atria and ventricles, which may be governed by other regulatory mechanisms. If these mechanisms could be deduced, de-silencing of the B isoform may represent a therapeutic strategy in 5'-XLDC patients.

Background: Gene transfer using adeno-associated viral (AAV) vectors has been successfully applied in the retina for the treatment of inherited retinal dystrophies. Recently, microRNAs have been exploited to fine-tune transgene expression improving therapeutic outcomes. Here we evaluated the ability of retinal-expressed microRNAs to restrict AAV-mediated transgene expression to specific retinal cell types that represent the main targets of common inherited blinding conditions. Methodology/Principal Findings: To this end, we generated AAV2/5 vectors expressing EGFP and containing four tandem copies of miR-124 or miR-204 complementary sequences in the 3′UTR of the transgene expression cassette. These vectors were administered subretinally to adult C57BL/6 mice and Large White pigs. Our results demonstrate that miR-124 and miR-204 target sequences can efficiently restrict AAV2/5-mediated transgene expression to retinal pigment epithelium and photoreceptors, respectively, in mice and pigs. Interestingly, transgene restriction was observed at low vector doses relevant to therapy. Conclusions: We conclude that microRNA-mediated regulation of transgene expression can be applied in the retina to either restrict to a specific cell type the robust expression obtained using ubiquitous promoters or to provide an additional layer of gene expression regulation when using cell-specific promoters. © 2011 Karali et al.

Vax2 is an eye-specific homeobox gene, the inactivation of which in mouse leads to alterations in the establishment of a proper dorsoventral eye axis during embryonic development. To dissect the molecular pathways in which Vax2 is involved, we performed a transcriptome analysis of Vax2–/– mice throughout the main stages of eye development. We found that some of the enzymes involved in retinoic acid (RA) metabolism in the eye show significant variations of their expression levels in mutant mice. In particular, we detected an expansion of the expression domains of the RA-catabolizing enzymes Cyp26a1 and Cyp26c1, and a downregulation of the RA-synthesizing enzyme Raldh3. These changes determine a significant expansion of the RA-free zone towards the ventral part of the eye. At postnatal stages of eye development, Vax2 inactivation led to alterations of the regional expression of the cone photoreceptor genes Opn1sw (S-Opsin) and Opn1mw (M-Opsin), which were significantly rescued after RA administration. We confirmed the above described alterations of gene expression in the Oryzias latipes (medaka fish) model system using both Vax2 gain- and loss-of-function assays. Finally, a detailed morphological and functional analysis of the adult retina in mutant mice revealed that Vax2 is necessary for intraretinal pathfinding of retinal ganglion cells in mammals. These data demonstrate for the first time that Vax2 is both necessary and sufficient for the control of intraretinal RA metabolism, which in turn contributes to the appropriate expression of cone opsins in the vertebrate eye.

The safety and efficacy of gene therapy for inherited retinal diseases is being tested in humans affected with Leber's congenital amaurosis (LCA), an autosomal recessive blinding disease. Three independent studies have provided evidence that the subretinal administration of adeno-associated viral (AAV) vectors encoding RPE65 in patients affected with LCA2 due to mutations in the RPE65 gene, is safe and, in some cases, results in efficacy. We evaluated the long-term safety and efficacy (global effects on retinal/visual function) resulting from subretinal administration of AAV2-hRPE65v2. Both the safety and the efficacy noted at early timepoints persist through at least 1.5 years after injection in the three LCA2 patients enrolled in the low dose cohort of our trial. A transient rise in neutralizing antibodies to AAV capsid was observed but there was no humoral response to RPE65 protein. The persistence of functional amelioration suggests that AAV-mediated gene transfer to the human retina does not elicit immunological responses which cause significant loss of transduced cells. The persistence of physiologic effect supports the possibility that gene therapy may influence LCA2 disease progression. The safety of the intervention and the stability of the improvement in visual and retinal function in these subjects support the use of AAV-mediated gene augmentation therapy for treatment of inherited retinal diseases.

Background Gene therapy has the potential to reverse disease or prevent further deterioration of vision in patients with incurable inherited retinal degeneration. We therefore did a phase 1 trial to assess the effect of gene therapy on retinal and visual function in children and adults with Leber's congenital amaurosis.Methods We assessed the retinal and visual function in 12 patients (aged 8-44 years) with RPE65-associated Leber's congenital amaurosis given one subretinal injection of adeno-associated virus (AAV) containing a gene encoding a protein needed for the isomerohydrolase activity of the retinal pigment epithelium (AAV2-hRPE65v2) in the worst eye at low (1.5x10(10) vector genomes), medium (4.8x10(10) vector genomes), or high dose (1.5x10(11) vector genomes) for up to 2 years.Findings AAV2-hRPE65v2 was well tolerated and all patients showed sustained improvement in subjective and objective measurements of vision (ie, dark adaptometry, pupillometry, electroretinography, nystagmus, and ambulatory behaviour). Patients had at least a 2 log unit increase in pupillary light responses, and an 8-year-old child had nearly the same level of light sensitivity as that in age-matched normal-sighted individuals. The greatest improvement was noted in children, all of whom gained ambulatory vision. The study is registered with ClinicalTrials.gov, number NCT00516477.Interpretation The safety, extent, and stability of improvement in vision in all patients support the use of AAV mediated gene therapy for treatment of inherited retinal diseases, with early intervention resulting in the best potential gain. Background: Gene therapy has the potential to reverse disease or prevent further deterioration of vision in patients with incurable inherited retinal degeneration. We therefore did a phase 1 trial to assess the effect of gene therapy on retinal and visual function in children and adults with Leber's congenital amaurosis. Methods: We assessed the retinal and visual function in 12 patients (aged 8-44 years) with RPE65-associated Leber's congenital amaurosis given one subretinal injection of adeno-associated virus (AAV) containing a gene encoding a protein needed for the isomerohydrolase activity of the retinal pigment epithelium (AAV2-hRPE65v2) in the worst eye at low (1·5×1010 vector genomes), medium (4·8×1010 vector genomes), or high dose (1·5×1011 vector genomes) for up to 2 years. Findings: AAV2-hRPE65v2 was well tolerated and all patients showed sustained improvement in subjective and objective measurements of vision (ie, dark adaptometry, pupillometry, electroretinography, nystagmus, and ambulatory behaviour). Patients had at least a 2 log unit increase in pupillary light responses, and an 8-year-old child had nearly the same level of light sensitivity as that in age-matched normal-sighted individuals. The greatest improvement was noted in children, all of whom gained ambulatory vision. The study is registered with ClinicalTrials.gov, number NCT00516477. Interpretation: The safety, extent, and stability of improvement in vision in all patients support the use of AAV-mediated gene therapy for treatment of inherited retinal diseases, with early intervention resulting in the best potential gain. Funding: Center for Cellular and Molecular Therapeutics at the Children's Hospital of Philadelphia, Foundation Fighting Blindness, Telethon, Research to Prevent Blindness, F M Kirby Foundation, Mackall Foundation Trust, Regione Campania Convenzione, European Union, Associazione Italiana Amaurosi Congenita di Leber, Fund for Scientific Research, Fund for Research in Ophthalmology, and National Center for Research Resources. © 2009 Elsevier Ltd. All rights reserved.

Lysosomes are organelles central to degradation and recycling processes in animal cells. Whether lysosomal activity is coordinated to respond to cellular needs remains unclear. We found that most lysosomal genes exhibit coordinated transcriptional behavior and are regulated by the transcription factor EB (TFEB). Under aberrant lysosomal storage conditions, TFEB translocated from the cytoplasm to the nucleus, resulting in the activation of its target genes. TFEB overexpression in cultured cells induced lysosomal biogenesis and increased the degradation of complex molecules, such as glycosaminoglycans and the pathogenic protein that causes Huntington's disease. Thus, a genetic program controls lysosomal biogenesis and function, providing a potential therapeutic target to enhance cellular clearing in lysosomal storage disorders and neurodegenerative diseases.

About 20% of cases with 7q deletion syndrome is associated with holoprosencephaly (HPE), due to deletion of the Sonic Hedgehog (SHH) gene (mapping to 7q36). The occurrence of severe forms of holoprosencephaly is higher in cases of 7q deletion associated with partial trisomies involving different parts of the genomes than in patients with pure 7q deletion. All cases of 7q deletion associated with 3p duplication reported to date have been associated with severe forms of holoprosencephaly, and a gene(s) on distal 3p has (have) been hypothesized to be responsible for HPE phenotype when in triple dose. Here we describe a patient with unbalanced 3p;7q translocation, showing 7q deletion (including SHH gene) and 3p duplication (complete karyotype was 46,XY,der(7)t(3;7)(p26.3;q36.1)), presenting with a relatively mild phenotype, consisting of microphthalmia and microcephaly, without cerebral anomalies typical of holoprosencephaly. Possible involvement of some genes on 3p in determining such a mild phenotype is discussed.

p63, a p53 family member, is essential for the development of various stratified epithelia and is one of the earliest markers of many ectodermal structures, including the epidermis, oral mucosa, apical ectodermal ridge, and mammary gland. Genetic regulatory mechanisms controlling p63 spatial expression during development have not yet been defined. Using a genomic approach, we identified an evolutionarily conserved cis-regulatory element, located 160 kb downstream of the first p63 exon, which functions as a keratinocyte-specific enhancer and is sufficient to recapitulate expression of the endogenous gene during mouse embryogenesis. Dissection of the p63 enhancer activity revealed a positive autoregulatory loop in which the p63 proteins directly bind to and are essential regulators of the enhancer. Accordingly, transactivating p63 isoforms induce endogenous p63 expression in cells that do not normally express this gene, whereas dominant negative isoforms suppress p63 expression in keratinocytes. In addition the transcription factor AP-2 also binds to the enhancer and cooper- ates with p63 to induce its activity. These results demonstrate that a long-range autoregulatory loop is involved in the regulation of p63 expression during embryonic development and in adult cells.

Background: Ataxia with oculomotor apraxia type 2 (AOA2) is characterized by onset between age 10 and 22 years, cerebellar atrophy, peripheral neuropathy, oculomotor apraxia (OMA), and elevated serum alpha-fetoprotein (AFP) levels. Recessive mutations in SETX have been described in AOA2 patients. Objective: To describe the clinical features of AOA2 and to identify the SETX mutations in 10 patients from four Italian families. Methods: The patients underwent clinical examination, routine laboratory tests, nerve conduction studies, sural nerve biopsy, and brain MRI. All were screened for SETX mutations. Results: All the patients had cerebellar features, including limb and truncal ataxia, and slurred speech. OMA was observed in two patients, extrapyramidal symptoms in two, and mental impairment in three. High serum AFP levels, motor and sensory axonal neuropathy, and marked cerebellar atrophy on MRI were detected in all the patients who underwent these examinations. Sural nerve biopsy revealed a severe depletion of large myelinated fibers in one patient, and both large and small myelinated fibers in another. Postmortem findings are also reported in one of the patients. Four different homozygous SETX mutations were found (a large-scale deletion, a missense change, a single-base deletion, and a splice-site mutation). Conclusions: The clinical phenotype of oculomotor apraxia type 2 is fairly homogeneous, showing only subtle intrafamilial variability. OMA is an inconstant finding. The identification of new mutations expands the array of SETX variants, and the finding of a missense change outside the helicase domain suggests the existence of at least one more functional region in the N-terminus of senataxin.

Oculodentodigital dysplasia (ODDD) is a rare autosomal dominant pleiotropic disorder, caused by mutations in the Connexin 43 gene (GJA1) [Paznekas et al. (2003): Am J Hum Genet 72:408-418], which is localized to human chromosome 6q22-q23. Here, we describe the identification of a novel heterozygous missense mutation in the GJA1 gene, (H194P) in an Italian family previously reported to be affected by isolated autosomal dominant microphthalmia [Vingolo et al. (1994): J Med Genet 31:721-725]. Careful clinical re-evaluation revealed that this family shows an atypical form of ODDD, characterized by the predominance of the ocular involvement and by the absence of hand and/or foot syndactyly. The mutation affects an amino acid residue localized in the second extracellular domain of the Cx43 protein and highly conserved across evolution. This finding confirms the highly variable phenotypic expression caused by GJA1 mutations.

We describe two couples of sibs from a southern Italian family affected by epilepsy, myoclonus, mental retardation and slight ataxia. Onset was between 4 and 12 years and the course slowly progressive. The clinical picture suggested the diagnosis of Unverricht–Lundborg disease. Molecular study excluded linkage to EPM1. Other possible causes of progressive myoclonus epilepsy were also excluded.