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Elena Aller - One of the best experts on this subject based on the ideXlab platform.
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unravelling the pathogenic role and genotype phenotype correlation of the USH2A p cys759phe variant among spanish families
PLOS ONE, 2018Co-Authors: Raquel Perezcarro, Elena Aller, Gema Garciagarcia, Fiona Blancokelly, Lilian Galbismartinez, Blanca Garciasandoval, Pablo Minguez, Marta Corton, Ignacio Mahillofernandez, Inmaculada MartinmeridaAbstract:Introduction Mutations in USH2A cause both isolated Retinitis Pigmentosa (RP) and Usher syndrome (that implies RP and hearing impairment). One of the most frequent variants identified in this gene and among these patients is the p.(Cys759Phe) change. However, the pathogenic role of this allele has been questioned since it was found in homozygosity in two healthy siblings of a Spanish family. To assess the causative role of USH2A p.(Cys759Phe) in autosomal recessive RP (ARRP) and Usher syndrome type II (USH2) and to establish possible genotype-phenotype correlations associated with p.(Cys759Phe), we performed a comprehensive genetic and clinical study in patients suffering from any of the two above-mentioned diseases and carrying at least one p.(Cys759Phe) allele. Materials and methods Diagnosis was set according to previously reported protocols. Genetic analyses were performed by using classical molecular and Next-Generation Sequencing approaches. Probands of 57 unrelated families were molecularly studied and 63 patients belonging to these families were phenotypically evaluated. Results Molecular analysis characterized 100% of the cases, identifying: 11 homozygous patients for USH2A p.(Cys759Phe), 42 compound heterozygous patients (12 of them with another missense USH2A pathogenic variant and 30 with a truncating USH2A variant), and 4 patients carrying the p.(Cys759Phe) allele and a pathogenic variant in another RP gene (PROM1, CNGB1 or RP1). No additional causative variants were identified in symptomatic homozygous patients. Statistical analysis of clinical differences between zygosity states yielded differences (p≤0.05) in age at diagnosis of RP and hypoacusis, and progression of visual field loss. Homozygosity of p.(Cys759Phe) and compound heterozygosity with another USH2A missense variant is associated with ARRP or ARRP plus late onset hypoacusis (OR = 20.62, CI = 95%, p = 0.041). Conclusions The present study supports the role of USH2A p.(Cys759Phe) in ARRP and USH2 pathogenesis, and demonstrates the clinical differences between different zygosity states. Phenotype-genotype correlations may guide the genetic characterization based upon specific clinical signs and may advise on the clinical management and prognosis based upon a specific genotype.
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clinical aspects of usher syndrome and the USH2A gene in a cohort of 433 patients
JAMA Ophthalmology, 2015Co-Authors: Fiona Blancokelly, Teresa Jaijo, José M. Millán, Elena Aller, Almudena Avilafernandez, Blanca Garciasandoval, Maria Isabel Lopezmolina, Ascension Gimenez, Carmen AyusoAbstract:IMPORTANCE: A new statistical approach is needed to describe the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. OBJECTIVES: To describe the primary phenotypic characteristics and differences between type I and type II Usher syndrome and to establish a phenotype-genotype correlation for the 2 most frequent mutations in the USH2A gene. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study at a genetics department, in which clinical evaluations were performed for 433 patients (297 unrelated families) who were classified as having type I, II, III, atypical, or unclassified Usher syndrome according to their clinical history, pedigree data, results from ophthalmological studies, and audiological, neurophysiological, and vestibular test results. Molecular studies were performed for 304 patients (256 unrelated families). The Mann-Whitney U test or the χ2 test was used for calculating the differences between mean values for the analyzed parameters. MAIN OUTCOMES AND MEASURES: Age at diagnosis; age at onset of night blindness, visual field loss, visual acuity loss, and cataracts; and severity and age at diagnosis of hearing loss. RESULTS: The comparison between patients with type I Usher syndrome and those with type II Usher syndrome revealed P < .001 for most items analyzed. The most frequent mutations in the USH2A gene were the p.Glu767Serfs*21 and p.Cys759Phe mutations, with an allelic frequency of 23.2% (63 of 272 alleles) and 8.1% (22 of 272 alleles), respectively. The phenotypic analysis for patients carrying p.Cys759Phe showed P < .001 for most items analyzed when compared with patients carrying p.Glu767Serfs*21 and when compared with patients carrying other mutations in the USH2A gene. None of the p.Cys759Phe patients exhibited a severe hearing loss phenotype, and more than 60% had only mild hearing loss. Most patients carrying the p.Glu767Serfs*21 mutation (72.1%) were moderately deaf. CONCLUSIONS AND RELEVANCE: Our study presents the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. Detailed genotype-phenotype correlations, as presented in our study, allow for a better correlation of clinical signs with a known genotype and can improve the clinical management, genetic counseling, and risk assessment of patients with Usher syndrome because an estimated prognosis of their disease can be made.
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novel deletions involving the USH2A gene in patients with usher syndrome and retinitis pigmentosa
Molecular Vision, 2014Co-Authors: Gema Garciagarcia, Teresa Jaijo, Elena Aller, Maria Jose Aparisi, Fiona Blancokelly, Lise Larrieu, Annefrancoise Roux, Carmen Ayuso, Valerie Faugere, José M. MillánAbstract:Purpose The aim of the present work was to identify and characterize large rearrangements involving the USH2A gene in patients with Usher syndrome and nonsyndromic retinitis pigmentosa.
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analysis of the USH2A gene in medaka fish oryzias latipes
PLOS ONE, 2013Co-Authors: Elena Aller, Ana V Sanchezsanchez, Javier U Chicote, Gema Garciagarcia, P Udaondo, Laura Cavalle, Marina Piquergil, Antonio Garciaespana, Manuel DiazllopisAbstract:Patients suffering from Usher syndrome (USH) exhibit sensorineural hearing loss, retinitis pigmentosa (RP) and, in some cases, vestibular dysfunction. USH is the most common genetic disorder affecting hearing and vision and is included in a group of hereditary pathologies associated with defects in ciliary function known as ciliopathies. This syndrome is clinically classified into three types: USH1, USH2 and USH3. USH2 accounts for well over one-half of all Usher cases and mutations in the USH2A gene are responsible for the majority of USH2 cases, but also for atypical Usher syndrome and recessive non-syndromic RP. Because medaka fish (Oryzias latypes) is an attractive model organism for genetic-based studies in biomedical research, we investigated the expression and function of the USH2A ortholog in this teleost species. Ol-USH2A encodes a protein of 5.445 aa codons, containing the same motif arrangement as the human USH2A. Ol-USH2A is expressed during early stages of medaka fish development and persists into adulthood. Temporal Ol-USH2A expression analysis using whole mount in situ hybridization (WMISH) on embryos at different embryonic stages showed restricted expression to otoliths and retina, suggesting that Ol-USH2A might play a conserved role in the development and/or maintenance of retinal photoreceptors and cochlear hair cells. Knockdown of Ol-USH2A in medaka fish caused embryonic developmental defects (small eyes and heads, otolith malformations and shortened bodies with curved tails) resulting in late embryo lethality. These embryonic defects, observed in our study and in other ciliary disorders, are associated with defective cell movement specifically implicated in left-right (LR) axis determination and planar cell polarity (PCP).
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functional analysis of splicing mutations in myo7a and USH2A genes
Clinical Genetics, 2011Co-Authors: Teresa Jaijo, Elena Aller, Gema Garciagarcia, Maria Jose Aparisi, C Najera, Miguel Carballo, Imma Hernan, Maria Jose Gamundi, José M. MillánAbstract:Jaijo T, Aller E, Aparisi MJ, Garcia-Garcia G, Hernan I, Gamundi MJ, Najera C, Carballo M, Millan JM. Functional analysis of splicing mutations in MYO7A and USH2A genes. Usher syndrome is defined by the association of sensorineural hearing loss, retinitis pigmentosa and variable vestibular dysfunction. Many disease-causative mutations have been identified in MYO7A and USH2A genes, which play a major role in Usher syndrome type I and type II, respectively. The pathogenic nature of mutations that lead to premature stop codons is not questioned; nevertheless, additional studies are needed to verify the pathogenicity of some changes such as those putatively involved in the splice process. Five putative splice-site variants were detected in our cohort of patients: c.2283−1G>T and c.5856G>A in MYO7A and c.1841−2A>G, c.2167+5G>A and c.5298+1G>C in the USH2A gene. In this study, we analyze these changes with bioinformatic tools and investigate the expression of MYO7A and USH2A transcripts through hybrid minigene assays. Our study showed that all five mutations abolished the consensus splice site producing the skipping of involved exons. In addition, for variant c.2167+5G>A, a new donor splice site was observed. Our data reveal the pathogenic nature of the analyzed variants. The fact that splicing mutations led to in-frame or out-of-frame alterations cannot explain phenotypic differences, thus, genotype–phenotype correlations cannot be inferred.
José M. Millán - One of the best experts on this subject based on the ideXlab platform.
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antisense oligonucleotide based splice correction for USH2A associated retinal degeneration caused by a frequent deep intronic mutation
Molecular therapy. Nucleic acids, 2016Co-Authors: Radulfus Wn Slijkerman, Ronald J E Pennings, Gema Garciagarcia, Christel Vache, Mireille Claustres, Lisette Hetterschijt, Theo A Peters, Margo Dona, Bas P Hartel, José M. MillánAbstract:Usher syndrome (USH) is the most common cause of combined deaf-blindness in man. The hearing loss can be partly compensated by providing patients with hearing aids or cochlear implants, but the loss of vision is currently untreatable. In general, mutations in the USH2A gene are the most frequent cause of USH explaining up to 50% of all patients worldwide. The first deep-intronic mutation in the USH2A gene (c.7595-2144A>G) was reported in 2012, leading to the insertion of a pseudoexon (PE40) into the mature USH2A transcript. When translated, this PE40-containing transcript is predicted to result in a truncated non-functional USH2A protein. In this study, we explored the potential of antisense oligonucleotides (AONs) to prevent aberrant splicing of USH2A pre-mRNA as a consequence of the c.7595-2144A>G mutation. Engineered 2'-O-methylphosphorothioate AONs targeting the PE40 splice acceptor site and/or exonic splice enhancer regions displayed significant splice correction potential in both patient derived fibroblasts and a minigene splice assay for USH2A c.7595-2144A>G, whereas a non-binding sense oligonucleotide had no effect on splicing. Altogether, AON-based splice correction could be a promising approach for the development of a future treatment for USH2A-associated retinitis pigmentosa caused by the deep-intronic c.7595-2144A>G mutation.
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clinical aspects of usher syndrome and the USH2A gene in a cohort of 433 patients
JAMA Ophthalmology, 2015Co-Authors: Fiona Blancokelly, Teresa Jaijo, José M. Millán, Elena Aller, Almudena Avilafernandez, Blanca Garciasandoval, Maria Isabel Lopezmolina, Ascension Gimenez, Carmen AyusoAbstract:IMPORTANCE: A new statistical approach is needed to describe the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. OBJECTIVES: To describe the primary phenotypic characteristics and differences between type I and type II Usher syndrome and to establish a phenotype-genotype correlation for the 2 most frequent mutations in the USH2A gene. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study at a genetics department, in which clinical evaluations were performed for 433 patients (297 unrelated families) who were classified as having type I, II, III, atypical, or unclassified Usher syndrome according to their clinical history, pedigree data, results from ophthalmological studies, and audiological, neurophysiological, and vestibular test results. Molecular studies were performed for 304 patients (256 unrelated families). The Mann-Whitney U test or the χ2 test was used for calculating the differences between mean values for the analyzed parameters. MAIN OUTCOMES AND MEASURES: Age at diagnosis; age at onset of night blindness, visual field loss, visual acuity loss, and cataracts; and severity and age at diagnosis of hearing loss. RESULTS: The comparison between patients with type I Usher syndrome and those with type II Usher syndrome revealed P < .001 for most items analyzed. The most frequent mutations in the USH2A gene were the p.Glu767Serfs*21 and p.Cys759Phe mutations, with an allelic frequency of 23.2% (63 of 272 alleles) and 8.1% (22 of 272 alleles), respectively. The phenotypic analysis for patients carrying p.Cys759Phe showed P < .001 for most items analyzed when compared with patients carrying p.Glu767Serfs*21 and when compared with patients carrying other mutations in the USH2A gene. None of the p.Cys759Phe patients exhibited a severe hearing loss phenotype, and more than 60% had only mild hearing loss. Most patients carrying the p.Glu767Serfs*21 mutation (72.1%) were moderately deaf. CONCLUSIONS AND RELEVANCE: Our study presents the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. Detailed genotype-phenotype correlations, as presented in our study, allow for a better correlation of clinical signs with a known genotype and can improve the clinical management, genetic counseling, and risk assessment of patients with Usher syndrome because an estimated prognosis of their disease can be made.
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novel deletions involving the USH2A gene in patients with usher syndrome and retinitis pigmentosa
Molecular Vision, 2014Co-Authors: Gema Garciagarcia, Teresa Jaijo, Elena Aller, Maria Jose Aparisi, Fiona Blancokelly, Lise Larrieu, Annefrancoise Roux, Carmen Ayuso, Valerie Faugere, José M. MillánAbstract:Purpose The aim of the present work was to identify and characterize large rearrangements involving the USH2A gene in patients with Usher syndrome and nonsyndromic retinitis pigmentosa.
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functional analysis of splicing mutations in myo7a and USH2A genes
Clinical Genetics, 2011Co-Authors: Teresa Jaijo, Elena Aller, Gema Garciagarcia, Maria Jose Aparisi, C Najera, Miguel Carballo, Imma Hernan, Maria Jose Gamundi, José M. MillánAbstract:Jaijo T, Aller E, Aparisi MJ, Garcia-Garcia G, Hernan I, Gamundi MJ, Najera C, Carballo M, Millan JM. Functional analysis of splicing mutations in MYO7A and USH2A genes. Usher syndrome is defined by the association of sensorineural hearing loss, retinitis pigmentosa and variable vestibular dysfunction. Many disease-causative mutations have been identified in MYO7A and USH2A genes, which play a major role in Usher syndrome type I and type II, respectively. The pathogenic nature of mutations that lead to premature stop codons is not questioned; nevertheless, additional studies are needed to verify the pathogenicity of some changes such as those putatively involved in the splice process. Five putative splice-site variants were detected in our cohort of patients: c.2283−1G>T and c.5856G>A in MYO7A and c.1841−2A>G, c.2167+5G>A and c.5298+1G>C in the USH2A gene. In this study, we analyze these changes with bioinformatic tools and investigate the expression of MYO7A and USH2A transcripts through hybrid minigene assays. Our study showed that all five mutations abolished the consensus splice site producing the skipping of involved exons. In addition, for variant c.2167+5G>A, a new donor splice site was observed. Our data reveal the pathogenic nature of the analyzed variants. The fact that splicing mutations led to in-frame or out-of-frame alterations cannot explain phenotypic differences, thus, genotype–phenotype correlations cannot be inferred.
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A novel gene for Usher syndrome type 2: mutations in the long isoform of whirlin are associated with retinitis pigmentosa and sensorineural hearing loss
Human Genetics, 2007Co-Authors: Inga Ebermann, Hendrik P. N. Scholl, Peter Charbel Issa, Elvir Becirovic, Jürgen Lamprecht, Bernhard Jurklies, José M. Millán, Elena Aller, Diana Mitter, Hanno BolzAbstract:Usher syndrome is an autosomal recessive condition characterized by sensorineural hearing loss, variable vestibular dysfunction, and visual impairment due to retinitis pigmentosa (RP). The seven proteins that have been identified for Usher syndrome type 1 (USH1) and type 2 (USH2) may interact in a large protein complex. In order to identify novel USH genes, we followed a candidate strategy, assuming that mutations in proteins interacting with this “USH network” may cause Usher syndrome as well. The DFNB31 gene encodes whirlin, a PDZ scaffold protein with expression in both hair cell stereocilia and retinal photoreceptor cells. Whirlin represents an excellent candidate for USH2 because it binds to Usherin (USH2A) and VLGR1b (USH2C). Genotyping of microsatellite markers specific for the DFNB31 gene locus on chromosome 9q32 was performed in a German USH2 family that had been excluded for all known USH loci. Patients showed common haplotypes. Sequence analysis of DFNB31 revealed compound heterozygosity for a nonsense mutation, p.Q103X, in exon 1, and a mutation in the splice donor site of exon 2, c.837+1G>A. DFNB31 mutations appear to be a rare cause of Usher syndrome, since no mutations were identified in an additional 96 USH2 patients. While mutations in the C-terminal half of whirlin have previously been reported in non-syndromic deafness (DFNB31), both alterations identified in our USH2 family affect the long protein isoform. We propose that mutations causing Usher syndrome are probably restricted to exons 1–6 that are specific for the long isoform and probably crucial for retinal function. We describe a novel genetic subtype for Usher syndrome, which we named USH2D and which is caused by mutations in whirlin. Moreover, this is the first case of USH2 that is allelic to non-syndromic deafness.
Christian P Hamel - One of the best experts on this subject based on the ideXlab platform.
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genome editing in patient ipscs corrects the most prevalent USH2A mutations and reveals intriguing mutant mrna expression profiles
Molecular therapy. Methods & clinical development, 2020Co-Authors: Christian P Hamel, David Baux, Carla Sanjurjosoriano, Nejla Erkilic, Daria Mamaeva, Isabelle MeunierAbstract:Inherited retinal dystrophies (IRDs) are characterized by progressive photoreceptor degeneration and vision loss. Usher syndrome (USH) is a syndromic IRD characterized by retinitis pigmentosa (RP) and hearing loss. USH is clinically and genetically heterogeneous, and the most prevalent causative gene is USH2A. USH2A mutations also account for a large number of isolated autosomal recessive RP (arRP) cases. This high prevalence is due to two recurrent USH2A mutations, c.2276G>T and c.2299delG. Due to the large size of the USH2A cDNA, gene augmentation therapy is inaccessible. However, CRISPR/Cas9-mediated genome editing is a viable alternative. We used enhanced specificity Cas9 of Streptococcus pyogenes (eSpCas9) to successfully achieve seamless correction of the two most prevalent USH2A mutations in induced pluripotent stem cells (iPSCs) of patients with USH or arRP. Our results highlight features that promote high target efficacy and specificity of eSpCas9. Consistently, we did not identify any off-target mutagenesis in the corrected iPSCs, which also retained pluripotency and genetic stability. Furthermore, analysis of USH2A expression unexpectedly identified aberrant mRNA levels associated with the c.2276G>T and c.2299delG mutations that were reverted following correction. Taken together, our efficient CRISPR/Cas9-mediated strategy for USH2A mutation correction brings hope for a potential treatment for USH and arRP patients.
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generation of a human ipsc line inmi002 a carrying the most prevalent USH2A variant associated with usher syndrome type 2
Stem Cell Research, 2018Co-Authors: Carla Sanjurjosoriano, Christian P Hamel, Nejla Erkilic, Gael Manes, Gregor Dubois, Isabelle Meunier, Vasiliki KalatzisAbstract:Abstract We generated an induced pluripotent stem cell (iPSC) line using dermal fibroblasts from a patient with Usher syndrome type 2 (USH2). This individual was homozygous for the most prevalent variant reported in the USH2A gene, c.2299delG localized in exon 13. Reprogramming was performed using the non-integrative Sendai virus reprogramming method and the human OSKM transcription factor cocktail under feeder-free culture conditions. This iPSC line will be an invaluable tool for studying the pathophysiology of USH2 and for testing the efficacy of novel treatments.
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generation of an ipsc line inmi001 a carrying the two most common USH2A mutations from a compound heterozygote with non syndromic retinitis pigmentosa
Stem Cell Research, 2018Co-Authors: Christian P Hamel, Carla Sanjurjosoriano, Nejla Erkilic, Gael Manes, Gregor DuboisAbstract:Abstract We generated an induced pluripotent stem cell (iPSC) line from a patient with non-syndromic retinitis pigmentosa who is a compound heterozygote for the two most frequent USH2A variants, c.2276G > T and c.2299delG localized in exon 13. Patient fibroblasts were reprogrammed using the non-integrative Sendai virus reprogramming method and the human OSKM transcription factor cocktail. The generated cells were pluripotent and genetically stable. This iPSC line will be an important tool for studying the pathogenesis of these USH2A mutations and for developing treatments that, due their high prevalence, will target a large patient population.
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whole USH2A gene sequencing identifies several new deep intronic mutations
Human Mutation, 2016Co-Authors: Alessandro Liquori, Christian P Hamel, Christel Vache, David Baux, C Blanchet, Sue Malcolm, Michel Koenig, Mireille Claustres, Annefrancoise RouxAbstract:Deep intronic mutations leading to pseudoexon (PE) insertions are underestimated and most of these splicing alterations have been identified by transcript analysis, for instance, the first deep intronic mutation in USH2A, the gene most frequently involved in Usher syndrome type II (USH2). Unfortunately, analyzing USH2A transcripts is challenging and for 1.8%-19% of USH2 individuals carrying a single USH2A recessive mutation, a second mutation is yet to be identified. We have developed and validated a DNA next-generation sequencing approach to identify deep intronic variants in USH2A and evaluated their consequences on splicing. Three distinct novel deep intronic mutations have been identified. All were predicted to affect splicing and resulted in the insertion of PEs, as shown by minigene assays. We present a new and attractive strategy to identify deep intronic mutations, when RNA analyses are not possible. Moreover, the bioinformatics pipeline developed is independent of the gene size, implying the possible application of this approach to any disease-linked gene. Finally, an antisense morpholino oligonucleotide tested in vitro for its ability to restore splicing caused by the c.9959-4159A>G mutation provided high inhibition rates, which are indicative of its potential for molecular therapy.
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enrichment of lovd ushbases with 152 USH2A genotypes defines an extensive mutational spectrum and highlights missense hotspots
Human Mutation, 2014Co-Authors: David Baux, Christian P Hamel, Christel Vache, Lise Larrieu, C Blanchet, Isabelle Meunier, Valerie Faugere, Pierangela Castorina, B Puech, Dominique BonneauAbstract:Alterations of USH2A, encoding usherin, are responsible for more than 70% of cases of Usher syndrome type II (USH2), a recessive disorder that combines moderate to severe hearing loss and retinal degeneration. The longest USH2A transcript encodes usherin isoform b, a 5,202-amino-acid transmembrane protein with an exceptionally large extracellular domain consisting notably of a Laminin N-terminal domain and numerous Laminin EGF-like (LE) and Fibronectin type III (FN3) repeats. Mutations of USH2A are scattered throughout the gene and mostly private. Annotating these variants is therefore of major importance to correctly assign pathogenicity. We have extensively genotyped a novel cohort of 152 Usher patients and identified 158 different mutations, of which 93 are newly described. Pooling this new data with the existing pathogenic variants already incorporated in USHbases reveals several previously unappreciated features of the mutational spectrum. We show that parts of the protein are more likely to tolerate single amino acid variations, whereas others constitute pathogenic missense hotspots. We have found, in repeated LE and FN3 domains, a nonequal distribution of the missense mutations that highlights some crucial positions in usherin with possible consequences for the assessment of the pathogenicity of the numerous missense variants identified in USH2A.
Erwin Van Wijk - One of the best experts on this subject based on the ideXlab platform.
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visual prognosis in USH2A associated retinitis pigmentosa is worse for patients with usher syndrome type iia than for those with nonsyndromic retinitis pigmentosa
Ophthalmology, 2016Co-Authors: Laurence Pierrache, Erwin Van Wijk, Bas P Hartel, Cor W R J Cremers, Magda A Meestersmoor, Frans P M Cremers, Elfride De Baere, Julie De Zaeytijd, Mary J Van Schooneveld, Gislin DagnelieAbstract:Purpose USH2A mutations are an important cause of retinitis pigmentosa (RP) with or without congenital sensorineural hearing impairment. We studied genotype–phenotype correlations and compared visual prognosis in Usher syndrome type IIa and nonsyndromic RP. Design Clinic-based, longitudinal, multicenter study. Participants Consecutive patients with Usher syndrome type IIa (n = 152) and nonsyndromic RP (n = 73) resulting from USH2A mutations from ophthalmogenetic clinics in the Netherlands and Belgium. Methods Data on clinical characteristics, visual acuity, visual field measurements, retinal imaging, and electrophysiologic features were extracted from medical charts over a mean follow-up of 9 years. Cumulative lifetime risks of low vision and blindness were estimated using Kaplan-Meier survival analysis. Main Outcome Measures Low vision and blindness. Results Participant groups had similar distributions of gender (48% vs. 45% males in Usher syndrome type IIa vs. nonsydromic RP; P = 0.8), ethnicity (97% vs. 99% European; P = 0.3), and median follow-up time (6.5 years vs. 3 years; P = 0.3). Usher syndrome type IIa patients demonstrated symptoms at a younger age (median age, 15 years vs. 25 years; P P P P USH2A was associated mostly with the syndromic phenotype, whereas other combinations were present in both groups. We found novel variants in Usher syndrome type IIa (25%) and nonsyndromic RP (19%): 29 missense mutations, 10 indels, 14 nonsense mutations, 9 frameshift mutations, and 5 splice-site mutations. Conclusions Most patients with USH2A -associated RP have severe visual impairment by age 50. However, those with Usher syndrome type IIa have an earlier decline of visual function and a higher cumulative risk of visual impairment than those without nonsyndromic RP. Complete loss of function of the USH2A protein predisposes to Usher syndrome type IIa, but remnant protein function can lead to RP with or without hearing loss.
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The mitotic spindle protein SPAG5/Astrin connects to the Usher protein network postmitotically
Cilia, 2012Co-Authors: Ferry F J Kersten, Uwe Wolfrum, Erwin Van Wijk, Lisette Hetterschijt, Katharina Bauβ, Theo A Peters, Mariam G Aslanyan, Bert Van Der Zwaag, Jan Ee Keunen, Ronald RoepmanAbstract:Background Mutations in the gene for Usher syndrome 2A ( USH2A) are causative for non-syndromic retinitis pigmentosa and Usher syndrome, a condition that is the most common cause of combined deaf-blindness. To gain insight into the molecular pathology underlying USH2A-associated retinal degeneration, we aimed to identify interacting proteins of USH2A isoform B (USH2A^isoB) in the retina. Results We identified the centrosomal and microtubule-associated protein sperm-associated antigen (SPAG)5 in the retina. SPAG5 was also found to interact with another previously described USH2A^isoB interaction partner: the centrosomal ninein-like protein NINL^isoB. Using In situ hybridization, we found that Spag5 was widely expressed during murine embryonic development, with prominent signals in the eye, cochlea, brain, kidney and liver. SPAG5 expression in adult human tissues was detected by quantitative PCR, which identified expression in the retina, brain, intestine, kidney and testis. In the retina, Spag5, USH2A^isoB and Ninl^isoB were present at several subcellular structures of photoreceptor cells, and colocalized at the basal bodies. Conclusions Based on these results and on the suggested roles for USH proteins in vesicle transport and providing structural support to both the inner ear and the retina, we hypothesize that SPAG5, USH2A^isoB and NINL^isoB may function together in microtubule-based cytoplasmic trafficking of proteins that are essential for cilium formation, maintenance and/or function.
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a novel usher protein network at the periciliary reloading point between molecular transport machineries in vertebrate photoreceptor cells
Human Molecular Genetics, 2008Co-Authors: Tina Maerker, Erwin Van Wijk, Nora Overlack, Ferry F J Kersten, Joann Mcgee, Tobias Goldmann, Elisabeth Sehn, Ronald Roepman, Edward J Walsh, Hannie KremerAbstract:The human Usher syndrome (USH) is the most frequent cause of combined deaf-blindness. USH is genetically heterogeneous with at least 12 chromosomal loci assigned to three clinical types, USH1-3. Although these USH types exhibit similar phenotypes in human, the corresponding gene products belong to very different protein classes and families. The scaffold protein harmonin (USH1C) was shown to integrate all identified USH1 and USH2 molecules into protein networks. Here, we analyzed a protein network organized in the absence of harmonin by the scaffold proteins SANS (USH1G) and whirlin (USH2D). Immunoelectron microscopic analyses disclosed the colocalization of all network components in the apical inner segment collar and the ciliary apparatus of mammalian photoreceptor cells. In this complex, whirlin and SANS directly interact. Furthermore, SANS provides a linkage to the microtubule transport machinery, whereas whirlin may anchor USH2A isoform b and VLGR1b (very large G-protein coupled receptor 1b) via binding to their cytodomains at specific membrane domains. The long ectodomains of both transmembrane proteins extend into the gap between the adjacent membranes of the connecting cilium and the apical inner segment. Analyses of Vlgr1/del7TM mice revealed the ectodomain of VLGR1b as a component of fibrous links present in this gap. Comparative analyses of mouse and Xenopus photoreceptors demonstrated that this USH protein network is also part of the periciliary ridge complex in Xenopus. Since this structural specialization in amphibian photoreceptor cells defines a specialized membrane domain for docking and fusion of transport vesicles, we suggest a prominent role of the USH proteins in cargo shipment.
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the dfnb31 gene product whirlin connects to the usher protein network in the cochlea and retina by direct association with USH2A and vlgr1
Human Molecular Genetics, 2006Co-Authors: Erwin Van Wijk, Elena Aller, Heleen Te Brinke, Lies H Hoefsloot, Ferry F J Kersten, Theo A Peters, Bert Van Der Zwaag, Ulrike Zimmermann, Tina Marker, Cor W R J CremersAbstract:Mutations in the DFNB31 gene encoding the PDZ scaffold protein whirlin are causative for hearing loss in man and mouse. Whirlin is known to be essential for the elongation process of the stereocilia of sensory hair cells in the inner ear, though its complete spatial and temporal expression patterns remained elusive. Here, we demonstrate that, in embryonic development, the gene is not only expressed in the inner ear, but also in the developing brain and the retina. Various isoforms of whirlin are widely and differentially expressed, and we provide evidence that whirlin directly associates with USH2A isoform b and VLGR1b, two proteins that we previously reported to be part of the Usher protein interactome. These proteins co-localize with whirlin at the synaptic regions of both photoreceptor cells and outer hair cells in the cochlea. These findings indicate that whirlin is part of a macromolecular PDZ protein scaffold that functions in the organization of the pre- and/or postsynaptic side of photoreceptor and hair cell synapses. Whirlin might be involved in synaptic adhesion through interaction with USH2A and VLGR1b as well as in synaptic development as suggested by its spatial and temporal expression patterns. In addition, we demonstrate that whirlin, USH2A and Vlgr1b co-localize at the connecting cilium and the outer limiting membrane of photoreceptor cells and in spiral ganglion neurons of the inner ear. Our data show that whirlin is connected to the dynamic Usher protein interactome and indicate that whirlin has a pleiotropic function in both the retina and the inner ear.
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identification of 51 novel exons of the usher syndrome type 2a USH2A gene that encode multiple conserved functional domains and that are mutated in patients with usher syndrome type ii
American Journal of Human Genetics, 2004Co-Authors: Erwin Van Wijk, Ronald J E Pennings, Heleen Te Brinke, Annemarie Claassen, Lies H Hoefsloot, Cor W R J Cremers, Frans P M Cremers, Helger G Yntema, H KremerAbstract:The USH2A gene is mutated in patients with Usher syndrome type IIa, which is the most common subtype of Usher syndrome and is characterized by hearing loss and retinitis pigmentosa. Since mutation analysis by DNA sequencing of exons 1–21 revealed only ∼63% of the expected USH2A mutations, we searched for so-far-uncharacterized exons of the gene. We identified 51 novel exons at the 3′ end of the gene, and we obtained indications for alternative splicing. The putative protein encoded by the longest open reading frame harbors, in addition to the known functional domains, two laminin G and 28 fibronectin type III repeats, as well as a transmembrane region followed by an intracellular domain with a PDZ-binding domain at its C-terminal end. Semiquantitative expression profile analysis suggested a low level of expression for both the long and the short isoform(s) and partial overlap in spatial and temporal expression patterns. Mutation analysis in 12 unrelated patients with Usher syndrome, each with one mutation in exons 1–21, revealed three different truncating mutations in four patients and two missense mutations in one patient. The presence of pathogenic mutations in the novel exons indicates that at least one of the putative long isoforms of the USH2A protein plays a role in both hearing and vision.
Carmen Ayuso - One of the best experts on this subject based on the ideXlab platform.
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clinical aspects of usher syndrome and the USH2A gene in a cohort of 433 patients
JAMA Ophthalmology, 2015Co-Authors: Fiona Blancokelly, Teresa Jaijo, José M. Millán, Elena Aller, Almudena Avilafernandez, Blanca Garciasandoval, Maria Isabel Lopezmolina, Ascension Gimenez, Carmen AyusoAbstract:IMPORTANCE: A new statistical approach is needed to describe the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. OBJECTIVES: To describe the primary phenotypic characteristics and differences between type I and type II Usher syndrome and to establish a phenotype-genotype correlation for the 2 most frequent mutations in the USH2A gene. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study at a genetics department, in which clinical evaluations were performed for 433 patients (297 unrelated families) who were classified as having type I, II, III, atypical, or unclassified Usher syndrome according to their clinical history, pedigree data, results from ophthalmological studies, and audiological, neurophysiological, and vestibular test results. Molecular studies were performed for 304 patients (256 unrelated families). The Mann-Whitney U test or the χ2 test was used for calculating the differences between mean values for the analyzed parameters. MAIN OUTCOMES AND MEASURES: Age at diagnosis; age at onset of night blindness, visual field loss, visual acuity loss, and cataracts; and severity and age at diagnosis of hearing loss. RESULTS: The comparison between patients with type I Usher syndrome and those with type II Usher syndrome revealed P < .001 for most items analyzed. The most frequent mutations in the USH2A gene were the p.Glu767Serfs*21 and p.Cys759Phe mutations, with an allelic frequency of 23.2% (63 of 272 alleles) and 8.1% (22 of 272 alleles), respectively. The phenotypic analysis for patients carrying p.Cys759Phe showed P < .001 for most items analyzed when compared with patients carrying p.Glu767Serfs*21 and when compared with patients carrying other mutations in the USH2A gene. None of the p.Cys759Phe patients exhibited a severe hearing loss phenotype, and more than 60% had only mild hearing loss. Most patients carrying the p.Glu767Serfs*21 mutation (72.1%) were moderately deaf. CONCLUSIONS AND RELEVANCE: Our study presents the clinical differences between type I and type II Usher syndrome and between the 2 most frequent mutations in the USH2A gene. Detailed genotype-phenotype correlations, as presented in our study, allow for a better correlation of clinical signs with a known genotype and can improve the clinical management, genetic counseling, and risk assessment of patients with Usher syndrome because an estimated prognosis of their disease can be made.
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novel deletions involving the USH2A gene in patients with usher syndrome and retinitis pigmentosa
Molecular Vision, 2014Co-Authors: Gema Garciagarcia, Teresa Jaijo, Elena Aller, Maria Jose Aparisi, Fiona Blancokelly, Lise Larrieu, Annefrancoise Roux, Carmen Ayuso, Valerie Faugere, José M. MillánAbstract:Purpose The aim of the present work was to identify and characterize large rearrangements involving the USH2A gene in patients with Usher syndrome and nonsyndromic retinitis pigmentosa.
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identification of 14 novel mutations in the long isoform of USH2A in spanish patients with usher syndrome type ii
Journal of Medical Genetics, 2006Co-Authors: Elena Aller, Teresa Jaijo, C Najera, Magdalena Beneyto, Carmen Ayuso, S Oltra, M Baiget, Miguel Carballo, Guillermo Antinolo, Diana ValverdeAbstract:Mutations in USH2A gene have been shown to be responsible for Usher syndrome type II, an autosomal recessive disorder characterised by hearing loss and retinitis pigmentosa. USH2A was firstly described as consisting of 21 exons, but 52 novel exons at the 3' end of the gene were recently identified. In this report, a mutation analysis of the new 52 exons of USH2A gene was carried out in 32 unrelated patients in which both disease‐causing mutations could not be found after the screening of the first 21 exons of the USH2A gene. On analysing the new 52 exons, fourteen novel mutations were identified in 14 out of the 32 cases studied, including 7 missense, 5 frameshift, 1 duplication and a putative splice-site mutation.
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mutations in myosin viia myo7a and usherin USH2A in spanish patients with usher syndrome types i and ii respectively
Human Mutation, 2002Co-Authors: C Najera, José M. Millán, Elena Aller, Magdalena Beneyto, Jose Blanca, Ana Fontcuberta, Carmen AyusoAbstract:Usher syndrome is an autosomal recessive disorder characterized by congenital hearing impairment and retinitis pigmentosa. Three clinical types are known (USH1, USH2 and USH3), and there is an extensive genetic heterogeneity, with at least ten genes implicated. The most frequently mutated genes are MYO7A, which causes USH1B, and usherin, which causes USH2A. We carried out a mutation analysis of these two genes in the Spanish population. Analysis of the MYO7A gene in patients from 30 USH1 families and sporadic cases identified 32% of disease alleles, with mutation Q821X being the most frequent. Most of the remaining variants are private mutations. With regard to USH2, mutation 2299delG was detected in 25% of the Spanish patients. Altogether the mutations detected in USH2A families account for 23% of the disease alleles. © 2002 Wiley-Liss, Inc.
