The Experts below are selected from a list of 723 Experts worldwide ranked by ideXlab platform
Cristina Sobacchi - One of the best experts on this subject based on the ideXlab platform.
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autosomal recessive osteopetrosis type i description of pathogenic variant of TCIRG1 gene
Boletín médico del Hospital Infantil de México, 2019Co-Authors: Luis E Chavezguitron, Cristina Sobacchi, Tadeo Cerontorres, Echael Ochoaruiz, Sugey VillegashuescaAbstract:Introduccion: La osteopetrosis infantil maligna es una condicion rara cuyo origen es la deficiente reabsorcion osea por parte de los osteoclastos. Su diagnostico requiere un alto indice de sospecha. El tratamiento de eleccion es el trasplante alogenico de celulas hematopoyeticas. Los mejores desenlaces ocurren si el procedimiento se lleva a cabo antes de que ocurra dano a los nervios craneales. Caso clinico: Paciente masculino de 8 meses de edad fue referido a la consulta de hematologia por citopenias, hepatomegalia y falla para crecer. Se diagnostico osteopetrosis infantil maligna basandose en los hallazgos de la exploracion fisica, la alteracion del metabolismo del calcio y el fosforo y la hiperdensidad del hueso. Se obtuvo ADN del paciente y ambos padres; se demostro un heterocigosidad compuesta del gen TCIRG1 con una delecion (c.1809_1818del) no descrita previamente. Conclusiones: Una nueva mutacion patogenica de TCIRG1 se identifico en un paciente mexicano con osteopetrosis. Se ofrecio trasplante de celulas progenitoras hematopoyeticas como el mejor tratamiento disponible, pero fue rechazado por los padres. Se necesita un reconocimiento temprano y la implementacion del acceso generalizado a este procedimiento
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As Little as Needed: The Extraordinary Case of a Mild Recessive Osteopetrosis Owing to a Novel Splicing Hypomorphic Mutation in the TCIRG1 Geney
2016Co-Authors: Cristina Sobacchi, Maria Elena Caldana, Lucia Susani, Paolo Vezzoni, Ra Pangrazio, Antonio González‐meneses Lopez, Diego Pascual‐vaca Gomez, Anna VillaAbstract:Mutations in the TCIRG1 gene, coding for a subunit of the osteoclast proton pump, are responsible for more than 50 % of cases of human malignant autosomal recessive osteopetrosis (ARO), a rare inherited bone disease with increased bone density owing to a failure in bone resorption. A wide variety of mutations has been described, including missense, nonsense, small deletions/insertions, splice‐site mutations, and large genomic deletions, all leading to a similar severe presentation. So far, to the best of our knowledge, no report of a mild phenotype owing to recessive TCIRG1mutations is present neither in our series of more than 100 TCIRG1‐dependent ARO patients nor in the literature. Herewedescribe an 8‐year‐old patient referred to uswith a clinical diagnosis of ARO, basedon radiological findings; of note, no neurological or hematological defects were present in this girl. Surprisingly, we identified a novel nucleotide change in intron 15 of the TCIRG1 gene at the homozygous state, leading to the production of multiple aberrant transcripts, but also, more importantly, of a limited amount of the normal transcript. Our results show that a low level of normal TCIRG1 protein can dampen the clinical presentation of TCIRG1‐dependent ARO. On this basis, a small amount of protein might be sufficient to rescue, at least partially, the severe AR
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As Little as Needed: The Extraordinary Case of a Mild Recessive Osteopetrosis Owing to a Novel Splicing Hypomorphic Mutation in the TCIRG1 Gene†
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2014Co-Authors: Cristina Sobacchi, Alessandra Pangrazio, Antonio González-meneses López, Diego Pascual Vaca Gomez, Maria Elena Caldana, Lucia Susani, Paolo Vezzoni, Anna VillaAbstract:Mutations in the TCIRG1 gene, coding for a subunit of the osteoclast proton pump, are responsible for more than 50% of cases of human malignant autosomal recessive osteopetrosis (ARO), a rare inherited bone disease with increased bone density owing to a failure in bone resorption. A wide variety of mutations has been described, including missense, nonsense, small deletions/insertions, splice-site mutations, and large genomic deletions, all leading to a similar severe presentation. So far, to the best of our knowledge, no report of a mild phenotype owing to recessive TCIRG1 mutations is present neither in our series of more than 100 TCIRG1-dependent ARO patients nor in the literature. Here we describe an 8-year-old patient referred to us with a clinical diagnosis of ARO, based on radiological findings; of note, no neurological or hematological defects were present in this girl. Surprisingly, we identified a novel nucleotide change in intron 15 of the TCIRG1 gene at the homozygous state, leading to the production of multiple aberrant transcripts, but also, more importantly, of a limited amount of the normal transcript. Our results show that a low level of normal TCIRG1 protein can dampen the clinical presentation of TCIRG1-dependent ARO. On this basis, a small amount of protein might be sufficient to rescue, at least partially, the severe ARO phenotype, and this is particularly important when gene therapy approaches are considered. In addition, we would also recommend that the TCIRG1 gene be included in the molecular diagnosis of mild forms of human ARO. © 2014 Italian National Research Council. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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Erratum to: Autosomal recessive osteopetrosis: report of 41 novel mutations in the TCIRG1 gene and diagnostic implications
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteopor, 2012Co-Authors: Alessandra Pangrazio, Maria Elena Caldana, Paolo Vezzoni, Anna Villa, N. Lo Iacono, Stefano Mantero, Cristina SobacchiAbstract:Summary Here we report 41 novel mutations in the TCIRG1 gene that is responsible for the disease in more than 50% of ARO patients. The characterisation of mutations in this gene might be useful in the process of drug design for osteoporosis treatment.
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Characterization of a Novel Alu‐Alu Recombination‐Mediated Genomic Deletion in the TCIRG1 Gene in Five Osteopetrotic Patients
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2009Co-Authors: Alessandra Pangrazio, Cristina Sobacchi, Maria Elena Caldana, Lucia Susani, Anna Villa, Cristina Panaroni, Ercan Mihci, Maria Luigia Cavaliere, Silvia Giliani, Annalisa FrattiniAbstract:Human malignant autosomal recessive osteopetrosis (ARO) is a genetically heterogeneous disorder caused by reduced bone resorption by osteoclasts. Biallelic mutations in the TCIRG1 gene, encoding the a3 subunit of the vacuolar proton pump, are responsible for more than one half of ARO patients. However, a few patients with monoallelic mutations have been described, raising the possibility of a dominant-like TCIRG1-dependent osteopetrosis, of a digenic disease, or of peculiar mutations difficult to detect with standard methods. We describe here a novel genomic deletion in the TCIRG1 gene explaining why, in some patients, mutations in only one allele have previously been found. The analysis of a proband from a consanguineous Turkish family allowed us to define the deletion boundaries encompassing introns 10 and 13 and occurring within AluSx repeat sequences, suggesting Alu-mediated homologous recombination as a mechanism. An identical genomic deletion at the heterozygous level was found in four unrelated Italian families in whom only a single mutated allele has previously been found. TCIRG1 haplotype analysis in these five families suggests a possible common ancestral origin for this large deletion. In summary, we describe the identification of a novel genomic deletion in the TCIRG1 gene that is of clinical relevance, especially in prenatal diagnosis.
Paul J. Orchard - One of the best experts on this subject based on the ideXlab platform.
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TCIRG1 Transgenic Rescue of Osteoclast Function Using Induced Pluripotent Stem Cells Derived from Patients with Infantile Malignant Autosomal Recessive Osteopetrosis.
The Journal of bone and joint surgery. American volume, 2019Co-Authors: Weili Chen, Paul J. Orchard, Kirk Twaroski, Cindy R. Eide, Megan J. Riddle, Jakub TolarAbstract:Background:Osteoclasts are hematopoietic stem cell-derived multinucleated cells necessary for bone remodeling and resorption. TCIRG1 encodes a protein that is an adenosine triphosphate (ATP)-dependent vacuolar proton pump required for this process. Recessive loss-of-function mutations in both copies
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TCIRG1 dependent recessive osteopetrosis mutation analysis functional identification of the splicing defects and in vitro rescue by u1 snrna
Human Mutation, 2004Co-Authors: Lucia Susani, Cristina Sobacchi, Alessandra Pangrazio, Paolo Vezzoni, Anna Villa, Paul J. Orchard, Anna Taranta, Geert Mortier, Ravi Savarirayan, Alberto AlbertiniAbstract:Human malignant infantile osteopetrosis (arOP) is a genetically heterogeneous autosomal recessive disorder of bone metabolism. The TCIRG1 gene, encoding the a3 subunit of the vacuolar proton pump, which mediates the acidification of the bone/osteoclast interface, is responsible for more than one-half of the arOP patients. We performed genetic analysis of TCIRG1 in 55 arOP patients including 25 new cases and identified nine novel mutations. The two most frequent mutations, c.1674–1G>A (aberrant splicing: r.1674_1884del) and c.2005C>T (protein variation: p.Arg669X), found in 17 and 16 alleles, respectively, constituted 30% of all TCIRG1 abnormalities. They both originated in Northern Europe, p.Arg669X quite recently from West Flanders, Belgium. As substitutions in splicing regulatory sequences represented a large portion (40%; 44 alleles) of the TCIRG1 variations, we developed a functional splicing assay to distinguish between polymorphic variants and disease-causing mutations. Three intronic nucleotide substitutions flanking the splice sites (c.117+4A>T; c.1673+5G>A; and c.504–8G>A) were studied using hybrid minigenes and an abnormal processing of the transcripts was demonstrated in all cases. Cotransfection experiments with complementary U1 snRNAs performed in c.117+4A>T and c.1673+5G>A mutations showed that only in the first case was the defect at the 5′ splice site corrected, indicating that mutations near the invariant GT donor sites are mechanistically different. These findings indicate the feasibility of the hybrid minigene approach to detect splicing defects, particularly in patients in whom the RNA is not available. In addition, the present results suggest that modified U1 snRNAs may represent a new therapeutic strategy for arOP patients with a U1 snRNP-dependent splicing defect. Hum Mutat 24:225–235, 2004. © 2004 Wiley-Liss, Inc.
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In Vitro Differentiation of CD14 Cells From Osteopetrotic Subjects: Contrasting Phenotypes With TCIRG1, CLCN7, and Attachment Defects†
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2004Co-Authors: Harry C. Blair, Anna Villa, Christopher W. Borysenko, Paul H. Schlesinger, Sara E. Kalla, Beatrice B. Yaroslavskiy, Verónica García-palacios, Jennifer I. Oakley, Paul J. OrchardAbstract:We studied osteoclastic differentiation from normal and osteopetrotic human CD14 cells in vitro. Defects in acid transport, organic matrix removal, and cell fusion with deficient attachment were found. Analysis of genotypes showed that TCIRG1 anomalies correlated with acid transport defects, but surprisingly, organic matrix removal failure correlated with CLCN7 defects; an attachment defect had normal TCIRG1 and CLCN7. Introduction: Osteopetrotic subjects usually have normal macrophage activity, and despite identification of genetic defects associated with osteopetrosis, the specific developmental and biochemical defects in most cases are unclear. Indeed, patients with identical genotypes often have different clinical courses. We classified defects in osteoclast differentiation in vitro using four osteopetrotic subjects without immune or platelet defects, three of them severe infantile cases, compared with normals. Materials and Methods: Osteoclast differentiation used isolated CD14 cells; results were correlated with independent analysis of two key genes, CLCN7 and TCIRG1. CD14 cell attachment and cell surface markers and extent of differentiation in RANKL and colony-stimulating factor (CSF)-1 were studied using acid secretion, bone pitting, enzyme, and attachment proteins assays. Results and Conclusions: CD14 cells from all subjects had similar lysosomal and nonspecific esterase activity. With the exception of cells from one osteopetrotic subject, CD14 cells from osteopetrotic and control monocytes attached similarly to bone or tissue culture substrate. Cells from one osteopetrotic subject, with normal CLCN7 and TCIRG1, did not attach to bone, did not multinucleate, and formed no podosomes or actin rings in RANKL and CSF-1. Attachment defects are described in osteopetrosis, most commonly mild osteopetrosis with Glantzman's thrombasthenia. However, this case, with abnormal integrin αvβ3 aggregates and no osteoclasts, seems to be unique. Two subjects were compound heterozygotes for TCIRG1 defects; both had CD14 cells that attached to bone but did not acidify attachments; cell fusion and attachment occurred, however, in RANKL and CSF-1. This is consistent with TCIRG1, essential for H+-ATPase assembly at the ruffled border. A compound heterozygote for CLCN7 defects had CD14 cells that fused in vitro, attached to bone, and secreted acid, TRACP, and cathepsin K. However, lacunae were shallow and retained demineralized matrix. This suggests that CLCN7 may not limit H+-ATPase activity as hypothesized, but may be involved in control of organic matrix degradation or removal.
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TCIRG1‐dependent recessive osteopetrosis: Mutation analysis, functional identification of the splicing defects, and in vitro rescue by U1 snRNA
Human mutation, 2004Co-Authors: Lucia Susani, Cristina Sobacchi, Alessandra Pangrazio, Paolo Vezzoni, Anna Villa, Paul J. Orchard, Anna Taranta, Geert Mortier, Ravi Savarirayan, Alberto AlbertiniAbstract:Human malignant infantile osteopetrosis (arOP) is a genetically heterogeneous autosomal recessive disorder of bone metabolism. The TCIRG1 gene, encoding the a3 subunit of the vacuolar proton pump, which mediates the acidification of the bone/osteoclast interface, is responsible for more than one-half of the arOP patients. We performed genetic analysis of TCIRG1 in 55 arOP patients including 25 new cases and identified nine novel mutations. The two most frequent mutations, c.1674–1G>A (aberrant splicing: r.1674_1884del) and c.2005C>T (protein variation: p.Arg669X), found in 17 and 16 alleles, respectively, constituted 30% of all TCIRG1 abnormalities. They both originated in Northern Europe, p.Arg669X quite recently from West Flanders, Belgium. As substitutions in splicing regulatory sequences represented a large portion (40%; 44 alleles) of the TCIRG1 variations, we developed a functional splicing assay to distinguish between polymorphic variants and disease-causing mutations. Three intronic nucleotide substitutions flanking the splice sites (c.117+4A>T; c.1673+5G>A; and c.504–8G>A) were studied using hybrid minigenes and an abnormal processing of the transcripts was demonstrated in all cases. Cotransfection experiments with complementary U1 snRNAs performed in c.117+4A>T and c.1673+5G>A mutations showed that only in the first case was the defect at the 5′ splice site corrected, indicating that mutations near the invariant GT donor sites are mechanistically different. These findings indicate the feasibility of the hybrid minigene approach to detect splicing defects, particularly in patients in whom the RNA is not available. In addition, the present results suggest that modified U1 snRNAs may represent a new therapeutic strategy for arOP patients with a U1 snRNP-dependent splicing defect. Hum Mutat 24:225–235, 2004. © 2004 Wiley-Liss, Inc.
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defects in TCIRG1 subunit of the vacuolar proton pump are responsible for a subset of human autosomal recessive osteopetrosis
Nature Genetics, 2000Co-Authors: Annalisa Frattini, Cristina Sobacchi, Silvia Giliani, Paul J. Orchard, Mario Abinun, Jan P Mattsson, David Keeling, Ann Katrin Andersson, Pia Wallbrandt, Luigi ZeccaAbstract:Defects in TCIRG1 subunit of the vacuolar proton pump are responsible for a subset of human autosomal recessive osteopetrosis
Jason H. Moore - One of the best experts on this subject based on the ideXlab platform.
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Epiregulin (EREG) and human V-ATPase (TCIRG1): genetic variation, ethnicity and pulmonary tuberculosis susceptibility in Guinea-Bissau and The Gambia
Genes & Immunity, 2014Co-Authors: Marquitta J. White, Alessandra Tacconelli, J. S. Chen, Christian Wejse, Philip C. Hill, Victor F Gomes, D. R. Velez-edwards, L J Østergaard, T Hu, Jason H. MooreAbstract:We analyzed two West African samples (Guinea-Bissau: n =289 cases and 322 controls; The Gambia: n =240 cases and 248 controls) to evaluate single-nucleotide polymorphisms (SNPs) in Epiregulin ( EREG ) and V-ATPase ( T-cell immune regulator 1 ( TCIRG1 )) using single and multilocus analyses to determine whether previously described associations with pulmonary tuberculosis (PTB) in Vietnamese and Italians would replicate in African populations. We did not detect any significant single locus or haplotype associations in either sample. We also performed exploratory pairwise interaction analyses using Visualization of Statistical Epistasis Networks (ViSEN), a novel method to detect only interactions among multiple variables, to elucidate possible interaction effects between SNPs and demographic factors. Although we found no strong evidence of marginal effects, there were several significant pairwise interactions that were identified in either the Guinea-Bissau or the Gambian samples, two of which replicated across populations. Our results indicate that the effects of EREG and TCIRG1 variants on PTB susceptibility, to the extent that they exist, are dependent on gene–gene interactions in West African populations as detected with ViSEN. In addition, epistatic effects are likely to be influenced by inter- and intra-population differences in genetic or environmental context and/or the mycobacterial lineages causing disease.
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Epiregulin (EREG) and human V-ATPase (TCIRG1): genetic variation, ethnicity and pulmonary tuberculosis susceptibility in Guinea-Bissau and The Gambia.
Genes and immunity, 2014Co-Authors: Marquitta J. White, Alessandra Tacconelli, J. S. Chen, Christian Wejse, Philip C. Hill, Victor F Gomes, D. R. Velez-edwards, Lars Østergaard, Jason H. MooreAbstract:Epiregulin ( EREG ) and human V-ATPase ( TCIRG1 ): genetic variation, ethnicity and pulmonary tuberculosis susceptibility in Guinea-Bissau and The Gambia
Lucia Susani - One of the best experts on this subject based on the ideXlab platform.
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As Little as Needed: The Extraordinary Case of a Mild Recessive Osteopetrosis Owing to a Novel Splicing Hypomorphic Mutation in the TCIRG1 Geney
2016Co-Authors: Cristina Sobacchi, Maria Elena Caldana, Lucia Susani, Paolo Vezzoni, Ra Pangrazio, Antonio González‐meneses Lopez, Diego Pascual‐vaca Gomez, Anna VillaAbstract:Mutations in the TCIRG1 gene, coding for a subunit of the osteoclast proton pump, are responsible for more than 50 % of cases of human malignant autosomal recessive osteopetrosis (ARO), a rare inherited bone disease with increased bone density owing to a failure in bone resorption. A wide variety of mutations has been described, including missense, nonsense, small deletions/insertions, splice‐site mutations, and large genomic deletions, all leading to a similar severe presentation. So far, to the best of our knowledge, no report of a mild phenotype owing to recessive TCIRG1mutations is present neither in our series of more than 100 TCIRG1‐dependent ARO patients nor in the literature. Herewedescribe an 8‐year‐old patient referred to uswith a clinical diagnosis of ARO, basedon radiological findings; of note, no neurological or hematological defects were present in this girl. Surprisingly, we identified a novel nucleotide change in intron 15 of the TCIRG1 gene at the homozygous state, leading to the production of multiple aberrant transcripts, but also, more importantly, of a limited amount of the normal transcript. Our results show that a low level of normal TCIRG1 protein can dampen the clinical presentation of TCIRG1‐dependent ARO. On this basis, a small amount of protein might be sufficient to rescue, at least partially, the severe AR
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As Little as Needed: The Extraordinary Case of a Mild Recessive Osteopetrosis Owing to a Novel Splicing Hypomorphic Mutation in the TCIRG1 Gene†
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2014Co-Authors: Cristina Sobacchi, Alessandra Pangrazio, Antonio González-meneses López, Diego Pascual Vaca Gomez, Maria Elena Caldana, Lucia Susani, Paolo Vezzoni, Anna VillaAbstract:Mutations in the TCIRG1 gene, coding for a subunit of the osteoclast proton pump, are responsible for more than 50% of cases of human malignant autosomal recessive osteopetrosis (ARO), a rare inherited bone disease with increased bone density owing to a failure in bone resorption. A wide variety of mutations has been described, including missense, nonsense, small deletions/insertions, splice-site mutations, and large genomic deletions, all leading to a similar severe presentation. So far, to the best of our knowledge, no report of a mild phenotype owing to recessive TCIRG1 mutations is present neither in our series of more than 100 TCIRG1-dependent ARO patients nor in the literature. Here we describe an 8-year-old patient referred to us with a clinical diagnosis of ARO, based on radiological findings; of note, no neurological or hematological defects were present in this girl. Surprisingly, we identified a novel nucleotide change in intron 15 of the TCIRG1 gene at the homozygous state, leading to the production of multiple aberrant transcripts, but also, more importantly, of a limited amount of the normal transcript. Our results show that a low level of normal TCIRG1 protein can dampen the clinical presentation of TCIRG1-dependent ARO. On this basis, a small amount of protein might be sufficient to rescue, at least partially, the severe ARO phenotype, and this is particularly important when gene therapy approaches are considered. In addition, we would also recommend that the TCIRG1 gene be included in the molecular diagnosis of mild forms of human ARO. © 2014 Italian National Research Council. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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Characterization of a Novel Alu‐Alu Recombination‐Mediated Genomic Deletion in the TCIRG1 Gene in Five Osteopetrotic Patients
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2009Co-Authors: Alessandra Pangrazio, Cristina Sobacchi, Maria Elena Caldana, Lucia Susani, Anna Villa, Cristina Panaroni, Ercan Mihci, Maria Luigia Cavaliere, Silvia Giliani, Annalisa FrattiniAbstract:Human malignant autosomal recessive osteopetrosis (ARO) is a genetically heterogeneous disorder caused by reduced bone resorption by osteoclasts. Biallelic mutations in the TCIRG1 gene, encoding the a3 subunit of the vacuolar proton pump, are responsible for more than one half of ARO patients. However, a few patients with monoallelic mutations have been described, raising the possibility of a dominant-like TCIRG1-dependent osteopetrosis, of a digenic disease, or of peculiar mutations difficult to detect with standard methods. We describe here a novel genomic deletion in the TCIRG1 gene explaining why, in some patients, mutations in only one allele have previously been found. The analysis of a proband from a consanguineous Turkish family allowed us to define the deletion boundaries encompassing introns 10 and 13 and occurring within AluSx repeat sequences, suggesting Alu-mediated homologous recombination as a mechanism. An identical genomic deletion at the heterozygous level was found in four unrelated Italian families in whom only a single mutated allele has previously been found. TCIRG1 haplotype analysis in these five families suggests a possible common ancestral origin for this large deletion. In summary, we describe the identification of a novel genomic deletion in the TCIRG1 gene that is of clinical relevance, especially in prenatal diagnosis.
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characterization of a novel alu alu recombination mediated genomic deletion in the TCIRG1 gene in five osteopetrotic patients
Journal of Bone and Mineral Research, 2009Co-Authors: Alessandra Pangrazio, Cristina Sobacchi, Maria Elena Caldana, Lucia Susani, Anna Villa, Cristina Panaroni, Ercan Mihci, Maria Luigia Cavaliere, Silvia Giliani, Annalisa FrattiniAbstract:Human malignant autosomal recessive osteopetrosis (ARO) is a genetically heterogeneous disorder caused by reduced bone resorption by osteoclasts. Biallelic mutations in the TCIRG1 gene, encoding the a3 subunit of the vacuolar proton pump, are responsible for more than one half of ARO patients. However, a few patients with monoallelic mutations have been described, raising the possibility of a dominant-like TCIRG1-dependent osteopetrosis, of a digenic disease, or of peculiar mutations difficult to detect with standard methods. We describe here a novel genomic deletion in the TCIRG1 gene explaining why, in some patients, mutations in only one allele have previously been found. The analysis of a proband from a consanguineous Turkish family allowed us to define the deletion boundaries encompassing introns 10 and 13 and occurring within AluSx repeat sequences, suggesting Alu-mediated homologous recombination as a mechanism. An identical genomic deletion at the heterozygous level was found in four unrelated Italian families in whom only a single mutated allele has previously been found. TCIRG1 haplotype analysis in these five families suggests a possible common ancestral origin for this large deletion. In summary, we describe the identification of a novel genomic deletion in the TCIRG1 gene that is of clinical relevance, especially in prenatal diagnosis.
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TCIRG1 dependent recessive osteopetrosis mutation analysis functional identification of the splicing defects and in vitro rescue by u1 snrna
Human Mutation, 2004Co-Authors: Lucia Susani, Cristina Sobacchi, Alessandra Pangrazio, Paolo Vezzoni, Anna Villa, Paul J. Orchard, Anna Taranta, Geert Mortier, Ravi Savarirayan, Alberto AlbertiniAbstract:Human malignant infantile osteopetrosis (arOP) is a genetically heterogeneous autosomal recessive disorder of bone metabolism. The TCIRG1 gene, encoding the a3 subunit of the vacuolar proton pump, which mediates the acidification of the bone/osteoclast interface, is responsible for more than one-half of the arOP patients. We performed genetic analysis of TCIRG1 in 55 arOP patients including 25 new cases and identified nine novel mutations. The two most frequent mutations, c.1674–1G>A (aberrant splicing: r.1674_1884del) and c.2005C>T (protein variation: p.Arg669X), found in 17 and 16 alleles, respectively, constituted 30% of all TCIRG1 abnormalities. They both originated in Northern Europe, p.Arg669X quite recently from West Flanders, Belgium. As substitutions in splicing regulatory sequences represented a large portion (40%; 44 alleles) of the TCIRG1 variations, we developed a functional splicing assay to distinguish between polymorphic variants and disease-causing mutations. Three intronic nucleotide substitutions flanking the splice sites (c.117+4A>T; c.1673+5G>A; and c.504–8G>A) were studied using hybrid minigenes and an abnormal processing of the transcripts was demonstrated in all cases. Cotransfection experiments with complementary U1 snRNAs performed in c.117+4A>T and c.1673+5G>A mutations showed that only in the first case was the defect at the 5′ splice site corrected, indicating that mutations near the invariant GT donor sites are mechanistically different. These findings indicate the feasibility of the hybrid minigene approach to detect splicing defects, particularly in patients in whom the RNA is not available. In addition, the present results suggest that modified U1 snRNAs may represent a new therapeutic strategy for arOP patients with a U1 snRNP-dependent splicing defect. Hum Mutat 24:225–235, 2004. © 2004 Wiley-Liss, Inc.
Anna Villa - One of the best experts on this subject based on the ideXlab platform.
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As Little as Needed: The Extraordinary Case of a Mild Recessive Osteopetrosis Owing to a Novel Splicing Hypomorphic Mutation in the TCIRG1 Geney
2016Co-Authors: Cristina Sobacchi, Maria Elena Caldana, Lucia Susani, Paolo Vezzoni, Ra Pangrazio, Antonio González‐meneses Lopez, Diego Pascual‐vaca Gomez, Anna VillaAbstract:Mutations in the TCIRG1 gene, coding for a subunit of the osteoclast proton pump, are responsible for more than 50 % of cases of human malignant autosomal recessive osteopetrosis (ARO), a rare inherited bone disease with increased bone density owing to a failure in bone resorption. A wide variety of mutations has been described, including missense, nonsense, small deletions/insertions, splice‐site mutations, and large genomic deletions, all leading to a similar severe presentation. So far, to the best of our knowledge, no report of a mild phenotype owing to recessive TCIRG1mutations is present neither in our series of more than 100 TCIRG1‐dependent ARO patients nor in the literature. Herewedescribe an 8‐year‐old patient referred to uswith a clinical diagnosis of ARO, basedon radiological findings; of note, no neurological or hematological defects were present in this girl. Surprisingly, we identified a novel nucleotide change in intron 15 of the TCIRG1 gene at the homozygous state, leading to the production of multiple aberrant transcripts, but also, more importantly, of a limited amount of the normal transcript. Our results show that a low level of normal TCIRG1 protein can dampen the clinical presentation of TCIRG1‐dependent ARO. On this basis, a small amount of protein might be sufficient to rescue, at least partially, the severe AR
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As Little as Needed: The Extraordinary Case of a Mild Recessive Osteopetrosis Owing to a Novel Splicing Hypomorphic Mutation in the TCIRG1 Gene†
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research, 2014Co-Authors: Cristina Sobacchi, Alessandra Pangrazio, Antonio González-meneses López, Diego Pascual Vaca Gomez, Maria Elena Caldana, Lucia Susani, Paolo Vezzoni, Anna VillaAbstract:Mutations in the TCIRG1 gene, coding for a subunit of the osteoclast proton pump, are responsible for more than 50% of cases of human malignant autosomal recessive osteopetrosis (ARO), a rare inherited bone disease with increased bone density owing to a failure in bone resorption. A wide variety of mutations has been described, including missense, nonsense, small deletions/insertions, splice-site mutations, and large genomic deletions, all leading to a similar severe presentation. So far, to the best of our knowledge, no report of a mild phenotype owing to recessive TCIRG1 mutations is present neither in our series of more than 100 TCIRG1-dependent ARO patients nor in the literature. Here we describe an 8-year-old patient referred to us with a clinical diagnosis of ARO, based on radiological findings; of note, no neurological or hematological defects were present in this girl. Surprisingly, we identified a novel nucleotide change in intron 15 of the TCIRG1 gene at the homozygous state, leading to the production of multiple aberrant transcripts, but also, more importantly, of a limited amount of the normal transcript. Our results show that a low level of normal TCIRG1 protein can dampen the clinical presentation of TCIRG1-dependent ARO. On this basis, a small amount of protein might be sufficient to rescue, at least partially, the severe ARO phenotype, and this is particularly important when gene therapy approaches are considered. In addition, we would also recommend that the TCIRG1 gene be included in the molecular diagnosis of mild forms of human ARO. © 2014 Italian National Research Council. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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lentiviral gene transfer of TCIRG1 into peripheral blood cd34 cells restores osteoclast function in infantile malignant osteopetrosis
Bone, 2013Co-Authors: Ilana Moscatelli, Christian Schneider Thudium, Morten Asser Karsdal, Ansgar Schulz, Carmen Flores, Maria Askmyr, Natasja Stæhr Gudmann, Nanna Merete Andersen, Oscar Porras, Anna VillaAbstract:Infantile malignant osteopetrosis (IMO) is a rare, lethal, autosomal recessive disorder characterized by non-functional osteoclasts. More than 50% of the patients have mutations in the TCIRG1 gene, encoding for a subunit of the osteoclast proton pump. The aim of this study was to restore the resorptive function of IMO osteoclasts by lentiviral mediated gene transfer of the TCIRG1 cDNA. CD34(+) cells from peripheral blood of five IMO patients and from normal cord blood were transduced with lentiviral vectors expressing TCIRG1 and GFP under a SFFV promoter, expanded in culture and differentiated on bone slices to mature osteoclasts. qPCR analysis and western blot revealed increased mRNA and protein levels of TCIRG1, comparable to controls. Vector corrected IMO osteoclasts generated increased release of Ca(2+) and bone degradation product CTX-I into the media as well as increased formation of resorption pits in the bone slices, while non-corrected IMO osteoclasts failed to resorb bone. Resorption was approximately 70-80% of that of osteoclasts generated from cord blood. Furthermore, transduced CD34(+) cells successfully engrafted in NSG-mice. In conclusion we provide the first evidence of lentiviral-mediated correction of a human genetic disease affecting the osteoclastic lineage.
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Lentiviral gene transfer of TCIRG1 into peripheral blood CD34(+) cells restores osteoclast function in infantile malignant osteopetrosis.
Bone, 2013Co-Authors: Ilana Moscatelli, Christian Schneider Thudium, Morten Asser Karsdal, Ansgar Schulz, Carmen Flores, Maria Askmyr, Natasja Stæhr Gudmann, Nanna Merete Andersen, Oscar Porras, Anna VillaAbstract:Infantile malignant osteopetrosis (IMO) is a rare, lethal, autosomal recessive disorder characterized by non-functional osteoclasts. More than 50% of the patients have mutations in the TCIRG1 gene, encoding for a subunit of the osteoclast proton pump. The aim of this study was to restore the resorptive function of IMO osteoclasts by lentiviral mediated gene transfer of the TCIRG1 cDNA. CD34(+) cells from peripheral blood of five IMO patients and from normal cord blood were transduced with lentiviral vectors expressing TCIRG1 and GFP under a SFFV promoter, expanded in culture and differentiated on bone slices to mature osteoclasts. qPCR analysis and western blot revealed increased mRNA and protein levels of TCIRG1, comparable to controls. Vector corrected IMO osteoclasts generated increased release of Ca(2+) and bone degradation product CTX-I into the media as well as increased formation of resorption pits in the bone slices, while non-corrected IMO osteoclasts failed to resorb bone. Resorption was approximately 70-80% of that of osteoclasts generated from cord blood. Furthermore, transduced CD34(+) cells successfully engrafted in NSG-mice. In conclusion we provide the first evidence of lentiviral-mediated correction of a human genetic disease affecting the osteoclastic lineage.
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Erratum to: Autosomal recessive osteopetrosis: report of 41 novel mutations in the TCIRG1 gene and diagnostic implications
Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteopor, 2012Co-Authors: Alessandra Pangrazio, Maria Elena Caldana, Paolo Vezzoni, Anna Villa, N. Lo Iacono, Stefano Mantero, Cristina SobacchiAbstract:Summary Here we report 41 novel mutations in the TCIRG1 gene that is responsible for the disease in more than 50% of ARO patients. The characterisation of mutations in this gene might be useful in the process of drug design for osteoporosis treatment.
