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Jodeh W, Katz AJ, Hart M, Warden SJ, Niziolek P, Alam I, Ing S, Polgreen LE, Imel EA, Econs MJ. Autosomal Dominant Osteopetrosis (ADO) Caused by a Missense Variant in the TCIRG1 Gene. J Clin Endocrinol Metab 2024; 109:1726-1732. [PMID: 38261998 PMCID: PMC11180502 DOI: 10.1210/clinem/dgae040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 01/03/2024] [Accepted: 01/18/2024] [Indexed: 01/25/2024]
Abstract
CONTEXT Autosomal dominant osteopetrosis (ADO) is a rare genetic disorder resulting from impaired osteoclastic bone resorption. Clinical manifestations frequently include fractures, osteonecrosis (particularly of the jaw or maxilla), osteomyelitis, blindness, and/or bone marrow failure. ADO usually results from heterozygous missense variants in the Chloride Channel 7 gene (CLCN7) that cause disease by a dominant negative mechanism. Variants in the T-cell immune regulator 1 gene (TCIRG1) are commonly identified in autosomal recessive osteopetrosis but have only been reported in 1 patient with ADO. CASE DESCRIPTION Here, we report 3 family members with a single heterozygous missense variant (p.Gly579Arg) in TCIRG1 who have a phenotype consistent with ADO. Three of 5 protein prediction programs suggest this variant likely inhibits the function of TCIRG1. CONCLUSION This is the first description of adult presentation of ADO caused by a TCIRG1 variant. Similar to families with ADO from CLCN7 mutations, this variant in TCIRG1 results in marked phenotype variability, with 2 subjects having severe disease and the third having very mild disease. This family report implicates TCIRG1 missense mutations as a cause of ADO and demonstrates that the marked phenotypic variability in ADO may extend to disease caused by TCIRG1 missense mutations.
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Affiliation(s)
- Wade Jodeh
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Amy J Katz
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Marian Hart
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Stuart J Warden
- Department of Physical Therapy, Indiana University School of Health & Human Sciences, Indianapolis, IN 46202, USA
| | - Paul Niziolek
- Department of Radiology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Imranul Alam
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Steven Ing
- Division of Endocrinology, Diabetes, and Metabolism, Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
| | - Lynda E Polgreen
- The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Erik A Imel
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Michael J Econs
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Tüysüz B, Usluer E, Uludağ Alkaya D, Ocak S, Saygılı S, Şeker A, Apak H. The molecular spectrum of Turkish osteopetrosis and related osteoclast disorders with natural history, including a candidate gene, CCDC120. Bone 2023; 177:116897. [PMID: 37704070 DOI: 10.1016/j.bone.2023.116897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/21/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023]
Abstract
BACKGROUND Osteopetrosis and related osteoclastic disorders are a heterogeneous group of inherited diseases characterized by increased bone density. The aim of this study is to investigate the molecular spectrum and natural history of the clinical and radiological features of these disorders. METHODS 28 patients from 20 families were enrolled in the study; 20 of them were followed for a period of 1-16 years. Targeted gene analysis and whole-exome sequencing (WES) were performed. RESULTS Biallelic mutations in CLCN7 and TCIRG1 were detected in three families each, in TNFRSF11A and CA2 in two families each, and in SNX10 in one family in the osteopetrosis group. A heterozygous variant in CLCN7 was also found in one family. In the osteopetrosis and related osteoclast disorders group, three different variants in CTSK were detected in five families with pycnodysostosis and a SLC29A3 variant causing dysosteosclerosis was detected in one family. In autosomal recessive osteopetrosis (ARO), a malignant infantile form, four patients died during follow-up, two of whom had undergone hematopoietic stem cell transplantation. Interestingly, all patients had osteopetrorickets of the long bone metaphyses in infancy, typical skeletal features such as Erlenmeyer flask deformity and bone-in-bone appearance that developed toward the end of early childhood. Two siblings with a biallelic missense mutation in CLCN7 and one patient with the compound heterozygous novel splicing variants in intron 15 and 17 in TCIRG1 corresponded to the intermediate form of ARO (IARO); there was intrafamilial clinical heterogeneity in the family with the CLCN7 variant. One of two patients with IARO and distal tubular acidosis was found to have a large deletion in CA2. In one family, two siblings with a heterozygous mutation in CLCN7 were affected, whereas the father with the same mutation was asymptomatic. In WES analysis of three brothers from a family without mutations in osteopetrosis genes, a hemizygous missense variant in CCDC120, a novel gene, was found to be associated with high bone mass. CONCLUSION This study extended the natural history of the different types of osteopetrosis and also introduced a candidate gene, CCDC120, potentially causing osteopetrosis.
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Affiliation(s)
- Beyhan Tüysüz
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Genetics, Istanbul, Turkey.
| | - Esra Usluer
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Genetics, Istanbul, Turkey
| | - Dilek Uludağ Alkaya
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Genetics, Istanbul, Turkey
| | - Süheyla Ocak
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Hematology, Istanbul, Turkey
| | - Seha Saygılı
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Nephrology, Istanbul, Turkey
| | - Ali Şeker
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Orthopedics and Traumatology, Istanbul, Turkey
| | - Hilmi Apak
- Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Department of Pediatric Hematology, Istanbul, Turkey
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El-Kamah GY, Mehrez MI, Taher MB, El-Bassyouni HT, Gaber KR, Amr KS. Outlining the Clinical Profile of TCIRG1 14 Variants including 5 Novels with Overview of ARO Phenotype and Ethnic Impact in 20 Egyptian Families. Genes (Basel) 2023; 14:genes14040900. [PMID: 37107657 PMCID: PMC10137576 DOI: 10.3390/genes14040900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/15/2023] [Accepted: 03/17/2023] [Indexed: 04/29/2023] Open
Abstract
TCIRG1 gene mutations underlie osteopetrosis, a rare genetic disorder impacting osteoclast function with consequent brittle bones prone to fracture, in spite of being characterized by increased bone density. The disorder is known to exhibit marked genetic heterogeneity, has no treatment, and is lethal in most instances. There are reports of ethnic variations affecting bone mineral density and variants' expression as diverse phenotypes even within individuals descending from the same pedigree. We herein focus on one of osteopetrosis's three types: the autosomal recessive malignant form (MIM 259700) (ARO) that is almost always associated with severe clinical symptoms. We reviewed the results of about 1800 Egyptian exomes and we did not detect similar variants within our Egyptian dataset and secondary neurological deficit. We studied twenty Egyptian families: sixteen ARO patients, ten carrier parents with at least one ARO affected sib, and two fetuses. They were all subjected to thorough evaluation and TCIRG1 gene sequencing. Our results of twenty-eight individuals descending from twenty Egyptian pedigrees with at least one ARO patient, expand the phenotype as well as genotype spectrum of recessive mutations in the TCIRG1 gene by five novel pathogenic variants. Identifying TCIRG1 gene mutations in Egyptian patients with ARO allowed the provision of proper genetic counseling, carrier detection, and prenatal diagnosis starting with two families included herein. It also could pave the way to modern genomic therapeutic approaches.
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Affiliation(s)
- Ghada Y El-Kamah
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Mennat I Mehrez
- Oro-Dental Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Mohamed B Taher
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Hala T El-Bassyouni
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Khaled R Gaber
- Prenatal Diagnosis and Fetal Medicine Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Khalda S Amr
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
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Turan S. Osteopetrosis: Gene-based nosology and significance Dysosteosclerosis. Bone 2023; 167:116615. [PMID: 36402365 DOI: 10.1016/j.bone.2022.116615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 11/09/2022] [Accepted: 11/12/2022] [Indexed: 11/18/2022]
Abstract
Dysosteosclerosis (DSS) refers to skeletal dysplasias that radiographically feature focal appendicular osteosclerosis with variable platyspondyly. Genetic heterogeneity is increasingly reported for the DSS phenotype and now involves mutations of SLC29A3, TNFRSF11A, TCIRG1, LRRK1, and CSF1R. Typical radiological findings are widened radiolucent long bones with thin cortices yet dense irregular metaphyses, flattened vertebral bodies, dense ribs, and multiple fractures. However, the radiographic features of DSS evolve, and the metaphyseal and/or appendicular osteosclerosis variably fades with increasing patient age, likely due to some residual osteoclast function. Fractures are the principal presentation of DSS, and may even occur in infancy with SLC29A3-associated DSS. Cranial base sclerosis can lead to cranial nerve palsies such as optic atrophy, and may be the initial presentation, though not observed with SLC29A3-associated DSS. Gene-specific extra-skeletal features can be the main complication in some forms of DSS such as CSF1R- associated DSS. Further genetic heterogeneity is likely, especially for X-linked recessive DSS and cases currently with an unknown genetic defect. Distinguishing DSS can be challenging due to variable clinical and radiological features and an evolving phenotype. However, defining the DSS phenotype is important for predicting complications, prognosis, and instituting appropriate health surveillance and treatment.
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Affiliation(s)
- Serap Turan
- Pediatric Endocrinology and Diabetes, Marmara University School of Medicine, Istanbul, Turkey.
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Capo V, Abinun M, Villa A. Osteoclast rich osteopetrosis due to defects in the TCIRG1 gene. Bone 2022; 165:116519. [PMID: 35981697 DOI: 10.1016/j.bone.2022.116519] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 11/28/2022]
Abstract
Discovery that mutations in TCIRG1 (also known as Atp6i) gene are responsible for most instances of autosomal recessive osteopetrosis (ARO) heralded a new era for comprehension and treatment of this phenotypically heterogeneous rare bone disease. TCIRG1 encodes the a3 subunit, an essential isoform of the vacuolar ATPase proton pump involved in acidification of the osteoclast resorption lacuna and in secretory lysosome trafficking. TCIRG1 defects lead to inefficient bone resorption by nonfunctional osteoclasts seen in abundance on bone marrow biopsy, delineating this ARO as 'osteoclast-rich'. Presentation is usually in early childhood and features of extramedullary haematopoiesis (hepatosplenomegaly, anaemia, thrombocytopenia) due to bone marrow fibrosis, and cranial nerve impingement (blindness in particular). Impaired dietary calcium uptake due to high pH causes the co-occurrence of rickets, described as "osteopetrorickets". Osteoclast dysfunction leads to early death if untreated, and allogeneic haematopoietic stem cell transplantation is currently the treatment of choice. Studies of patients as well as of mouse models carrying spontaneous (the oc/oc mouse) or targeted disruption of Atp6i (TCIRG1) gene have been instrumental providing insight into disease pathogenesis and development of novel cellular therapies that exploit gene correction.
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Affiliation(s)
- Valentina Capo
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy; Institute of Genetic and Biomedical Research, Milan Unit, National Research Council, Milan, Italy
| | - Mario Abinun
- Children's Haematopoietic Stem Cell Transplantation Unit, Great North Children's Hospital, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Anna Villa
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy; Institute of Genetic and Biomedical Research, Milan Unit, National Research Council, Milan, Italy.
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Shinwari K, Rehman HM, Liu G, Bolkov MA, Tuzankina IA, Chereshnev VA. Novel Disease-Associated Missense Single-Nucleotide Polymorphisms Variants Predication by Algorithms Tools and Molecular Dynamics Simulation of Human TCIRG1 Gene Causing Congenital Neutropenia and Osteopetrosis. Front Mol Biosci 2022; 9:879875. [PMID: 35573728 PMCID: PMC9095858 DOI: 10.3389/fmolb.2022.879875] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/04/2022] [Indexed: 12/16/2022] Open
Abstract
T Cell Immune Regulator 1, ATPase H + Transporting V0 Subunit A3 (TCIRG1 gene provides instructions for making one part, the a3 subunit, of a large protein complex known as a vacuolar H + -ATPase (V-ATPase). V-ATPases are a group of similar complexes that act as pumps to move positively charged hydrogen atoms (protons) across membranes. Single amino acid changes in highly conserved areas of the TCIRG1 protein have been linked to autosomal recessive osteopetrosis and severe congenital neutropenia. We used multiple computational approaches to classify disease-prone single nucleotide polymorphisms (SNPs) in TCIRG1. We used molecular dynamics analysis to identify the deleterious nsSNPs, build mutant protein structures, and assess the impact of mutation. Our results show that fifteen nsSNPs (rs199902030, rs200149541, rs372499913, rs267605221, rs374941368, rs375717418, rs80008675, rs149792489, rs116675104, rs121908250, rs121908251, rs121908251, rs149792489 and rs116675104) variants are likely to be highly deleterious mutations as by incorporating them into wild protein they destabilize the wild protein structure and function. They are also located in the V-ATPase I domain, which may destabilize the structure and impair TCIRG1 protein activation, as well as reduce its ATPase effectiveness. These mutants have not yet been identified in patients suffering from CN and osteopetrosis while (G405R, R444L, and D517N) reported in our study are already associated with osteopetrosis. Mutation V52L reported in our study was identified in a patient suspected for CN. Finally, these mutants can help to further understand the broad pool of illness susceptibilities associated with TCIRG1 catalytic kinase domain activation and aid in the development of an effective treatment for associated diseases.
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Affiliation(s)
- Khyber Shinwari
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- *Correspondence: Khyber Shinwari,
| | - Hafiz Muzzammel Rehman
- School of Biochemistry and Biotechnology, University of the Punjab, Lahore, Pakistan
- Alnoorians Group of Institutes, Shad Bagh, Lahore, Pakistan
| | - Guojun Liu
- School of Life Science and Technology, Inner Mongolia University of Science and Technology, Baotou, China
| | - Mikhail A. Bolkov
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
| | - Irina A. Tuzankina
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
| | - Valery. A. Chereshnev
- Institute of Chemical Engineering, Department of Immunochemistry, Ural Federal University, Yekaterinburg, Russia
- Institute of Immunology and Physiology of the Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
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Liang H, Li N, Yao RE, Yu T, Ding L, Chen J, Wang J. Clinical and molecular characterization of five Chinese patients with autosomal recessive osteopetrosis. Mol Genet Genomic Med 2021; 9:e1815. [PMID: 34545712 PMCID: PMC8606217 DOI: 10.1002/mgg3.1815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 04/27/2021] [Accepted: 09/07/2021] [Indexed: 11/08/2022] Open
Abstract
Background Osteopetrosis is characterized by increased bone density and bone marrow cavity stenosis due to a decrease in the number of osteoclasts or the dysfunction of their differentiation and absorption properties usually caused by biallelic variants of the TCIRG1 and CLCN7 genes. Methods In this study, we describe five Chinese children who presented with anemia, thrombocytopenia, hepatosplenomegaly, repeated infections, and increased bone density. Whole‐exome sequencing identified five compound heterozygous variants of the CLCN7 and TCIRG1 genes in these patients. Results Patient 1 had a novel variant c.1555C>T (p.L519F) and a previously reported pathogenic variant c.2299C>T (p.R767W) in CLCN7. Patient 2 harbored a novel missense variant (c.1025T>C; p.L342P) and a novel splicing variant (c.286‐9G>A) in CLCN7. Patients 3A and 3B from one family displayed the same compound heterozygous TCIRG1 variant, including a novel frameshift variant (c.1370del; p.T457Tfs*71) and a novel splicing variant (c.1554+2T>C). In Patient 4, two novel variants were identified in the TCIRG1 gene: c.676G>T; p.E226* and c.1191del; p.P398Sfs*5. Patient 5 harbored two known pathogenic variants, c.909C>A (p.Y303*) and c.2008C>T (p.R670*), in TCIRG1. Analysis of the products obtained from the reverse transcription‐polymerase chain reaction revealed that the c.286‐9G>A variant in CLCN7 of patient 2 leads to intron 3 retention, resulting in the formation of a premature termination codon (p.E95Vfs*8). These five patients were eventually diagnosed with autosomal recessive osteopetrosis, and the three children with TCIRG1 variants received hematopoietic stem cell transplantation. Conclusions Our results expand the spectrum of variation of genes related to osteopetrosis and deepen the understanding of the relationship between the genotype and clinical characteristics of osteopetrosis.
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Affiliation(s)
- Huanhuan Liang
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health, Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Niu Li
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
| | - Ru-En Yao
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
| | - Tingting Yu
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
| | - Lixia Ding
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health, Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Chen
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health, Department of Hematology and Oncology, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Wang
- Department of Medical Genetics and Molecular Diagnostic Laboratory, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Clinical Molecular Diagnostics for Pediatrics, Shanghai, China
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Oh YK, Choi KE, Shin YJ, Kim ER, Kim JY, Kim MS, Cho SY, Jin DK. Autosomal Recessive Malignant Infantile Osteopetrosis Associated with a TCIRG1 Mutation: A Case Report of a Neonate Presenting with Hypocalcemia in South Korea. NEONATAL MEDICINE 2021. [DOI: 10.5385/nm.2021.28.3.133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Osteopetrosis refers to a group of genetic skeletal disorders characterized by osteosclerosis and fragile bones. Osteopetrosis can be classified into autosomal dominant, autosomal recessive, or X-linked forms, which might differ in clinical characteristics and disease severity. Autosomal recessive osteopetrosis, also known as malignant osteopetrosis, has an earlier onset, more serious clinical symptoms, and is usually fatal. We encountered a 1-day-old girl who was born full-term via vaginal delivery, which was complicated by meconium-stained amniotic fluid, cephalo-pelvic disproportion, and nuchal cord. Routine neonatal care was provided, in addition to blood tests and chest radiography to screen for sepsis, as well as skull radiography to rule out head injuries. Initial blood tests revealed hypocalcemia, which persisted on follow-up tests the next day. Radiographic examinations revealed diffusely increased bone density and a "space alien" appearance of the skull. Based on radiographic and laboratory findings, the infantile form of osteopetrosis was suspected and genetic testing for identification of the responsible gene. Eventually, a heterozygous mutation of the T cell immune regulator 1, ATPase H+ transporting V0 subunit a3 (TCIRG1) gene (c.292C>T) was identified, making this the first reported case of neonatal-onset malignant osteopetrosis with TCIRG1 mutation in South Korea. Early-onset hypocalcemia is common and usually results from prematurity, fetal growth restriction, maternal diabetes, perinatal asphyxia, and physiologic hypoparathyroidism. However, if hypocalcemia persists, we recommend considering 'infantile of osteopetrosis' as a rare cause of neonatal hypocalcemia and performing radiographic examinations to establish the diagnosis.
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Insights into the Cellular and Molecular Mechanisms That Govern the Fracture-Healing Process: A Narrative Review. J Clin Med 2021; 10:jcm10163554. [PMID: 34441849 PMCID: PMC8397080 DOI: 10.3390/jcm10163554] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Revised: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 12/28/2022] Open
Abstract
Fracture-healing is a complex multi-stage process that usually progresses flawlessly, resulting in restoration of bone architecture and function. Regrettably, however, a considerable number of fractures fail to heal, resulting in delayed unions or non-unions. This may significantly impact several aspects of a patient’s life. Not surprisingly, in the past few years, a substantial amount of research and number of clinical studies have been designed, aiming at shedding light into the cellular and molecular mechanisms that regulate fracture-healing. Herein, we present the current knowledge on the pathobiology of the fracture-healing process. In addition, the role of skeletal cells and the impact of marrow adipose tissue on bone repair is discussed. Unveiling the pathogenetic mechanisms that govern the fracture-healing process may lead to the development of novel, smarter, and more effective therapeutic strategies for the treatment of fractures, especially of those with large bone defects.
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Chu A, Zirngibl RA, Manolson MF. The V-ATPase a3 Subunit: Structure, Function and Therapeutic Potential of an Essential Biomolecule in Osteoclastic Bone Resorption. Int J Mol Sci 2021; 22:ijms22136934. [PMID: 34203247 PMCID: PMC8269383 DOI: 10.3390/ijms22136934] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/18/2021] [Accepted: 06/21/2021] [Indexed: 12/29/2022] Open
Abstract
This review focuses on one of the 16 proteins composing the V-ATPase complex responsible for resorbing bone: the a3 subunit. The rationale for focusing on this biomolecule is that mutations in this one protein account for over 50% of osteopetrosis cases, highlighting its critical role in bone physiology. Despite its essential role in bone remodeling and its involvement in bone diseases, little is known about the way in which this subunit is targeted and regulated within osteoclasts. To this end, this review is broadened to include the three other mammalian paralogues (a1, a2 and a4) and the two yeast orthologs (Vph1p and Stv1p). By examining the literature on all of the paralogues/orthologs of the V-ATPase a subunit, we hope to provide insight into the molecular mechanisms and future research directions specific to a3. This review starts with an overview on bone, highlighting the role of V-ATPases in osteoclastic bone resorption. We then cover V-ATPases in other location/functions, highlighting the roles which the four mammalian a subunit paralogues might play in differential targeting and/or regulation. We review the ways in which the energy of ATP hydrolysis is converted into proton translocation, and go in depth into the diverse role of the a subunit, not only in proton translocation but also in lipid binding, cell signaling and human diseases. Finally, the therapeutic implication of targeting a3 specifically for bone diseases and cancer is discussed, with concluding remarks on future directions.
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Penna S, Villa A, Capo V. Autosomal recessive osteopetrosis: mechanisms and treatments. Dis Model Mech 2021; 14:261835. [PMID: 33970241 PMCID: PMC8188884 DOI: 10.1242/dmm.048940] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Autosomal recessive osteopetrosis (ARO) is a severe inherited bone disease characterized by defective osteoclast resorption or differentiation. Clinical manifestations include dense and brittle bones, anemia and progressive nerve compression, which hamper the quality of patients' lives and cause death in the first 10 years of age. This Review describes the pathogenesis of ARO and highlights the strengths and weaknesses of the current standard of care, namely hematopoietic stem cell transplantation (HSCT). Despite an improvement in the overall survival and outcomes of HSCT, transplant-related morbidity and the pre-existence of neurological symptoms significantly limit the success of HSCT, while the availability of human leukocyte antigen (HLA)-matched donors still remains an open issue. Novel therapeutic approaches are needed for ARO patients, especially for those that cannot benefit from HSCT. Here, we review preclinical and proof-of-concept studies, such as gene therapy, systematic administration of deficient protein, in utero HSCT and gene editing. Summary: Autosomal recessive osteopetrosis is a heterogeneous and rare bone disease for which effective treatments are still lacking for many patients. Here, we review the literature on clinical, preclinical and proof-of-concept studies.
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Affiliation(s)
- Sara Penna
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.,Translational and Molecular Medicine (DIMET), University of Milano-Bicocca, Monza 20900, Italy
| | - Anna Villa
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.,Institute of Genetic and Biomedical Research, Milan Unit, National Research Council, Milan 20090, Italy
| | - Valentina Capo
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan 20132, Italy.,Institute of Genetic and Biomedical Research, Milan Unit, National Research Council, Milan 20090, Italy
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12
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Even-Or E, Stepensky P. How we approach malignant infantile osteopetrosis. Pediatr Blood Cancer 2021; 68:e28841. [PMID: 33314591 DOI: 10.1002/pbc.28841] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 12/14/2022]
Abstract
Malignant infantile osteopetrosis (MIOP) is a rare hereditary disorder characterized by excessive bone overgrowth due to a defect in bone marrow resorption by osteoclasts. In most cases, hematopoietic stem cell transplantation (HSCT) may correct bone metabolism but the rapidly progressing nature of this condition necessitates early diagnosis and prompt treatment to minimize irreversible cranial nerve damage. The management of patients with MIOP presents many unique challenges. In this review, the clinical management of patients with MIOP is discussed, including diagnosis, preparation for HSCT and special transplant considerations, management of unique HSCT complications, and long-term follow-up.
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Affiliation(s)
- Ehud Even-Or
- Faculty of Medicine, Hebrew University of Jerusalem, Israel, Department of Bone Marrow Transplantation and Cancer Immunotherapy, Hadassah Medical Center, Jerusalem, Israel
| | - Polina Stepensky
- Faculty of Medicine, Hebrew University of Jerusalem, Israel, Department of Bone Marrow Transplantation and Cancer Immunotherapy, Hadassah Medical Center, Jerusalem, Israel
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13
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Chen T, Sun J, Liu G, Yin C, Liu H, Qu L, Fang S, Shifra A, Gilad G. A Homozygous Mutation in 5' Untranslated Region of TNFRSF11A Leading to Molecular Diagnosis of Osteopetrosis Coinheritance With Wiskott-Aldrich Syndrome. J Pediatr Hematol Oncol 2021; 43:e264-e267. [PMID: 32097281 PMCID: PMC7993917 DOI: 10.1097/mph.0000000000001760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 01/30/2020] [Indexed: 01/17/2023]
Abstract
Wiskott-Aldrich syndrome (WAS) and osteopetrosis are 2 different, rare hereditary diseases. Here we report clinical and molecular genetics investigations on an infant patient with persistent thrombocytopenia and prolonged fever. He was clinical diagnosed as osteopetrosis according to clinical presentation, radiologic skeletal features, and bone biopsy results. Gene sequencing demonstrated a de novo homozygous mutation in 5'-untranslated region of TNFRSF11A, c.-45A>G, which is relating to osteopetrosis. Meanwhile, a hemizygous transition mutation in WAS gene, c.400G>A diagnosed the infant with WAS. This is the first clinical report for the diagnosis of osteopetrosis coinheritance with WAS in a single patient.
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Affiliation(s)
- Tianping Chen
- Departments of Hematology
- Hematology Research Centre, Anhui Provincial Research Institute of Pediatrics
- Hematology Research Centre, Anhui Medical University, Hefei, People’s Republic of China
| | - Jun Sun
- Orthopedics
- Hematology Research Centre, Anhui Provincial Research Institute of Pediatrics
| | - Guanghui Liu
- Neonatal
- Hematology Research Centre, Anhui Provincial Research Institute of Pediatrics
| | - Chuangao Yin
- Radiology
- Hematology Research Centre, Anhui Provincial Research Institute of Pediatrics
| | - Haipeng Liu
- Hematology Research Centre, Anhui Provincial Research Institute of Pediatrics
| | - Lijun Qu
- Departments of Hematology
- Hematology Research Centre, Anhui Provincial Research Institute of Pediatrics
| | - Shijin Fang
- Respiratory, Anhui Provincial Children’s Hospital
| | - Ash Shifra
- The Rina Zaizov Division of Pediatric Hematology-Oncology, Schneider Children’s Medical Center, Petah Tikva, Israel
| | - Gil Gilad
- The Rina Zaizov Division of Pediatric Hematology-Oncology, Schneider Children’s Medical Center, Petah Tikva, Israel
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14
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Capo V, Penna S, Merelli I, Barcella M, Scala S, Basso-Ricci L, Draghici E, Palagano E, Zonari E, Desantis G, Uva P, Cusano R, Sergi LS, Crisafulli L, Moshous D, Stepensky P, Drabko K, Kaya Z, Unal E, Gezdiric A, Menna G, Serafini M, Aiuti A, Locatelli SL, Carlo-Stella C, Schulz AS, Ficara F, Sobacchi C, Gentner B, Villa A. Expanded circulating hematopoietic stem/progenitor cells as novel cell source for the treatment of TCIRG1 osteopetrosis. Haematologica 2021; 106:74-86. [PMID: 31949009 PMCID: PMC7776247 DOI: 10.3324/haematol.2019.238261] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 01/09/2020] [Indexed: 11/16/2022] Open
Abstract
Allogeneic hematopoietic stem cell transplantation is the treatment of choice for autosomal recessive osteopetrosis caused by defects in the TCIRG1 gene. Despite recent progress in conditioning, a relevant number of patients are not eligible for allogeneic stem cell transplantation because of the severity of the disease and significant transplant-related morbidity. We exploited peripheral CD34+ cells, known to circulate at high frequency in the peripheral blood of TCIRG1-deficient patients, as a novel cell source for autologous transplantation of gene corrected cells. Detailed phenotypical analysis showed that circulating CD34+ cells have a cellular composition that resembles bone marrow, supporting their use in gene therapy protocols. Transcriptomic profile revealed enrichment in genes expressed by hematopoietic stem and progenitor cells (HSPCs). To overcome the limit of bone marrow harvest/ HSPC mobilization and serial blood drawings in TCIRG1 patients, we applied UM171-based ex-vivo expansion of HSPCs coupled with lentiviral gene transfer. Circulating CD34+ cells from TCIRG1-defective patients were transduced with a clinically-optimized lentiviral vector (LV) expressing TCIRG1 under the control of phosphoglycerate promoter and expanded ex vivo. Expanded cells maintained long-term engraftment capacity and multi-lineage repopulating potential when transplanted in vivo both in primary and secondary NSG recipients. Moreover, when CD34+ cells were differentiated in vitro, genetically corrected osteoclasts resorbed the bone efficiently. Overall, we provide evidence that expansion of circulating HSPCs coupled to gene therapy can overcome the limit of stem cell harvest in osteopetrotic patients, thus opening the way to future gene-based treatment of skeletal diseases caused by bone marrow fibrosis.
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Affiliation(s)
- Valentina Capo
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Sara Penna
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
- DIMET, University of Milano-Bicocca, Monza, Italy
| | - Ivan Merelli
- Institute for Biomedical Technologies, National Research Council, Segrate, Italy
| | - Matteo Barcella
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Serena Scala
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Luca Basso-Ricci
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Elena Draghici
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Eleonora Palagano
- CNR-IRGB, Milan Unit, Milan, Italy
- Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy
| | - Erika Zonari
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Giacomo Desantis
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Paolo Uva
- CRS4, Science and Technology Park Polaris, Pula, Italy
| | | | - Lucia Sergi Sergi
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Laura Crisafulli
- CNR-IRGB, Milan Unit, Milan, Italy
- Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy
| | - Despina Moshous
- Unite d'Immunologie, Hematologie et Rhumatologie Pediatriques (UIHR), Assistance Publique-Hopitaux de Paris, Hopital Necker-Enfants Malades, Paris, France
- INSERM UMR1163, Institut Imagine, Universite Paris Descartes-Sorbonne Paris Cite, Paris, France
| | - Polina Stepensky
- Department of Bone Marrow Transplantation and Cancer Immunotherapy, Hadassah University Hospital, Jerusalem, Israel
| | | | - Zühre Kaya
- Department of Pediatric Hematology, Gazi University, School of Medicine, Ankara, Turkey
| | - Ekrem Unal
- Erciyes University, Pediatric Hematology Oncology, Kayseri, Turkey
- Molecular Biology and Genetic Department, Gevher Nesibe Genom and Stem Cell Institution, Genome and Stem Cell Center (GENKOK), Erciyes University, Kayseri, Turkey
| | - Alper Gezdiric
- Department of Medical Genetics, Istanbul Health Science University, Kanuni Sultan Suleyman Training and Research Hospital, Istanbul, Turkey
| | - Giuseppe Menna
- Hemato-Oncology Unit, Department of Oncology, Pausilipon Hospital, Naples, Italy
| | | | - Alessandro Aiuti
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Silvia Laura Locatelli
- Department of Oncology and Hematology, Humanitas Cancer Center, Humanitas Clinical and Research Center, Rozzano, Italy
| | - Carmelo Carlo-Stella
- Department of Oncology and Hematology, Humanitas Cancer Center, Humanitas Clinical and Research Center, Rozzano, Italy
- Department of Biomedical Sciences, Humanitas University, Rozzano, Italy
| | - Ansgar S. Schulz
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Ulm, Germany
| | - Francesca Ficara
- CNR-IRGB, Milan Unit, Milan, Italy
- Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy
| | - Cristina Sobacchi
- CNR-IRGB, Milan Unit, Milan, Italy
- Humanitas Clinical and Research Center - IRCCS, Rozzano, Italy
| | - Bernhard Gentner
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Anna Villa
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), IRCCS San Raffaele Scientific Institute, Milan, Italy
- CNR-IRGB, Milan Unit, Milan, Italy
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15
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Chorin O, Yachelevich N, Mohamed K, Moscatelli I, Pappas J, Henriksen K, Evrony GD. Transcriptome sequencing identifies a noncoding, deep intronic variant in CLCN7 causing autosomal recessive osteopetrosis. Mol Genet Genomic Med 2020; 8:e1405. [PMID: 32691986 PMCID: PMC7549584 DOI: 10.1002/mgg3.1405] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/16/2020] [Accepted: 06/29/2020] [Indexed: 12/15/2022] Open
Abstract
Background Over half of children with rare genetic diseases remain undiagnosed despite maximal clinical evaluation and DNA‐based genetic testing. As part of an Undiagnosed Diseases Program applying transcriptome (RNA) sequencing to identify the causes of these unsolved cases, we studied a child with severe infantile osteopetrosis leading to cranial nerve palsies, bone deformities, and bone marrow failure, for whom whole‐genome sequencing was nondiagnostic. Methods We performed transcriptome (RNA) sequencing of whole blood followed by analysis of aberrant transcript isoforms and osteoclast functional studies. Results We identified a pathogenic deep intronic variant in CLCN7 creating an unexpected, frameshifting pseudoexon causing complete loss of function. Functional studies, including osteoclastogenesis and bone resorption assays, confirmed normal osteoclast differentiation but loss of osteoclast function. Conclusion This is the first report of a pathogenic deep intronic variant in CLCN7, and our approach provides a model for systematic identification of noncoding variants causing osteopetrosis—a disease for which molecular‐genetic diagnosis can be pivotal for potentially curative hematopoietic stem cell transplantation. Our work illustrates that cryptic splice variants may elude DNA‐only sequencing and supports broad first‐line use of transcriptome sequencing for children with undiagnosed diseases.
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Affiliation(s)
- Odelia Chorin
- Center for Human Genetics and Genomics, New York University Grossman School of Medicine, New York, NY, USA
| | - Naomi Yachelevich
- Division of Clinical Genetic Services, Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Khaled Mohamed
- Nordic Bioscience Biomarkers and Research, Herlev, Denmark
| | - Ilana Moscatelli
- Division of Molecular Medicine and Gene Therapy, Lund University, Lund, Sweden
| | - John Pappas
- Division of Clinical Genetic Services, Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Kim Henriksen
- Nordic Bioscience Biomarkers and Research, Herlev, Denmark
| | - Gilad D Evrony
- Center for Human Genetics and Genomics, New York University Grossman School of Medicine, New York, NY, USA.,Department of Pediatrics, and Department of Neuroscience & Physiology, New York University Grossman School of Medicine, New York, NY, USA
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16
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Generation of an immunodeficient mouse model of tcirg1-deficient autosomal recessive osteopetrosis. Bone Rep 2020; 12:100242. [PMID: 31938717 PMCID: PMC6953598 DOI: 10.1016/j.bonr.2020.100242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/23/2019] [Accepted: 01/04/2020] [Indexed: 01/16/2023] Open
Abstract
Background Autosomal recessive osteopetrosis is a rare skeletal disorder with increased bone density due to a failure in osteoclast bone resorption. In most cases, the defect is cell-autonomous, and >50% of patients bear mutations in the TCIRG1 gene, encoding for a subunit of the vacuolar proton pump essential for osteoclast resorptive activity. The only cure is hematopoietic stem cell transplantation, which corrects the bone pathology by allowing the formation of donor-derived functional osteoclasts. Therapeutic approaches using patient-derived cells corrected ex vivo through viral transduction or gene editing can be considered, but to date functional rescue cannot be demonstrated in vivo because a relevant animal model for xenotransplant is missing. Methods We generated a new mouse model, which we named NSG oc/oc, presenting severe autosomal recessive osteopetrosis owing to the Tcirg1oc mutation, and profound immunodeficiency caused by the NSG background. We performed neonatal murine bone marrow transplantation and xenotransplantation with human CD34+ cells. Results We demonstrated that neonatal murine bone marrow transplantation rescued NSG oc/oc mice, in line with previous findings in the oc/oc parental strain and with evidence from clinical practice in humans. Importantly, we also demonstrated human cell chimerism in the bone marrow of NSG oc/oc mice transplanted with human CD34+ cells. The severity and rapid progression of the disease in the mouse model prevented amelioration of the bone pathology; nevertheless, we cannot completely exclude that minor early modifications of the bone tissue might have occurred. Conclusion Our work paves the way to generating an improved xenograft model for in vivo evaluation of functional rescue of patient-derived corrected cells. Further refinement of the newly generated mouse model will allow capitalizing on it for an optimized exploitation in the path to novel cell therapies. Ex vivo corrected autologous HSCs might cure Autosomal Recessive Osteopetrosis (ARO). There is no animal model to prove in vivo functional rescue of corrected human cells. NSG oc/oc mice display osteoclast-rich cell-autonomous ARO and immunodeficiency. Human CD34+ cell-transplanted NSG oc/oc mice show human cell chimerism in the BM. Further improvements will allow in vivo evaluating corrected patient-derived cells.
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17
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Povoroznyuk V, Dedukh N, Bystrytska M, Musiienko A. Osteopetrosis: classification, pathomorphology, genetic disorders, clinical manifestations (literature review and clinical case report). ACTA ACUST UNITED AC 2019. [DOI: 10.22141/2224-1507.9.2.2019.172125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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18
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Zirngibl RA, Wang A, Yao Y, Manolson MF, Krueger J, Dupuis L, Mendoza-Londono R, Voronov I. Novel c.G630A TCIRG1 mutation causes aberrant splicing resulting in an unusually mild form of autosomal recessive osteopetrosis. J Cell Biochem 2019; 120:17180-17193. [PMID: 31111556 DOI: 10.1002/jcb.28979] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/19/2019] [Accepted: 03/22/2019] [Indexed: 12/22/2022]
Abstract
Autosomal recessive osteopetrosis (ARO) is a severe genetic bone disease characterized by high bone density due to mutations that affect formation or function of osteoclasts. Mutations in the a3 subunit of the vacuolar-type H+ -ATPase (encoded by T-cell immune regulator 1 [TCIRG1]) are responsible for ~50% of all ARO cases. We identified a novel TCIRG1 (c.G630A) mutation responsible for an unusually mild form of the disease. To characterize this mutation, osteoclasts were differentiated using peripheral blood monocytes from the patient (c.G630A/c.G630A), male sibling (+/+), unaffected female sibling (+/c.G630A), and unaffected parent (+/c.G630A). Osteoclast formation, bone-resorbing function, TCIRG1 protein, and mRNA expression levels were assessed. The c.G630A mutation did not affect osteoclast differentiation; however, bone-resorbing function was decreased. Both TCIRG1 protein and full-length TCIRG1 mRNA expression levels were also diminished in the affected patient's sample. The c.G630A mutation replaces the last nucleotide of exon 6 and may cause splicing defects. We analyzed the TCIRG1 splicing pattern between exons 4 to 8 and detected deletions of exons 5, 6, 7, and 5-6 (ΔE56). These deletions were only observed in c.G630A/c.G630A and +/c.G630A samples, but not in +/+ controls. Among these deletions, only ΔE56 maintained the reading frame and was predicted to generate an 85 kDa protein. Exons 5-6 encode an uncharacterized portion of the cytoplasmic N-terminal domain of a3, a domain not involved in proton translocation. To investigate the effect of ΔE56 on V-ATPase function, we transformed yeast with plasmids carrying full-length or truncated Vph1p, the yeast ortholog of a3. Both proteins were expressed; however, ΔE56-Vph1p transformed yeast failed to grow on Zn2+ -containing plates, a growth assay dependent on V-ATPase-mediated vacuolar acidification. In conclusion, our results show that the ΔE56 truncated protein is not functional, suggesting that the mild ARO phenotype observed in the patient is likely due to the residual full-length protein expression.
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Affiliation(s)
- Ralph A Zirngibl
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Andrew Wang
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Yeqi Yao
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Morris F Manolson
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Joerg Krueger
- Division of Hematology/Oncology and Blood and Marrow Transplant, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lucie Dupuis
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Roberto Mendoza-Londono
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Irina Voronov
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
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19
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Li L, Lv SS, Wang C, Yue H, Zhang ZL. Novel CLCN7 mutations cause autosomal dominant osteopetrosis type II and intermediate autosomal recessive osteopetrosis. Mol Med Rep 2019; 19:5030-5038. [PMID: 30942407 DOI: 10.3892/mmr.2019.10123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 03/27/2019] [Indexed: 12/21/2022] Open
Abstract
Osteopetrosis refers to a group of rare genetic bone diseases that are clinically characterized by increased bone mass and fragility. The principal pathogenic defect in patients with chloride channel 7 (CLCN7) gene‑dependent osteopetrosis is reduced osteoclast activity, which leads to decreased bone resorption. Mutations in the CLCN7 gene result in autosomal dominant osteopetrosis type II (ADO‑II), autosomal recessive osteopetrosis (ARO) and intermediate ARO (IARO). In the present study, eight mutations in the CLCN7 gene were identified in six patients with familial osteopetrosis and one patient with sporadic osteopetrosis. Heterozygous mutations c.856C>T (R286W), c.2236T>G (Y746D), c.296A>G (Y99C) and c.937G>A (E313K), and a splice mutation (c.2232‑2A>G) in the CLCN7 gene were detected in patients with ADO‑II. A homozygous mutation c.2377G>C (G793R), and a compound heterozygous mutation c.1409C>T (P470L) and c.647_648dupTG (K217X) were detected in two Chinese families with IARO. Among these mutations, two heterozygous mutations (c.2236T>G and c.2232‑2A>G), one homozygous mutation (c.2377G>C) and the compound heterozygous mutation (c.1409C>T and c.647_648dupTG) are novel, to the best of our knowledge. The present findings not only broaden the allelic spectrum of CLCN7 mutations, but also provide increased knowledge of the clinical phenotypes observed in Chinese patients with osteopetrosis.
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Affiliation(s)
- Li Li
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Shan-Shan Lv
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Chun Wang
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Hua Yue
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
| | - Zhen-Lin Zhang
- Metabolic Bone Disease and Genetic Research Unit, Department of Osteoporosis and Bone Disease, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, P.R. China
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Howaldt A, Nampoothiri S, Quell LM, Ozden A, Fischer-Zirnsak B, Collet C, de Vernejoul MC, Doneray H, Kayserili H, Kornak U. Sclerosing bone dysplasias with hallmarks of dysosteosclerosis in four patients carrying mutations in SLC29A3 and TCIRG1. Bone 2019; 120:495-503. [PMID: 30537558 DOI: 10.1016/j.bone.2018.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/01/2018] [Accepted: 12/06/2018] [Indexed: 11/23/2022]
Abstract
The osteopetroses and related sclerosing bone dysplasias can have a broad range of manifestations. Especially in the milder forms, sandwich vertebrae are an easily recognizable and reliable radiological hallmark. We report on four patients from three families presenting with sandwich vertebrae and platyspondyly. The long bone phenotypes were discordant with one patient showing modeling defects and patchy osteosclerosis, while the second displayed only metaphyseal sclerotic bands, and the third and fourth had extreme metaphyseal flaring with uniform osteosclerosis. Two of the four patients had experienced pathological fractures, two had developmental delay, but none showed cranial nerve damage, hepatosplenomegaly, or bone marrow failure. According to these clinical features the diagnoses ranged between intermediate autosomal recessive osteopetrosis and dysosteosclerosis. After exclusion of mutations in CLCN7 we performed gene panel and exome sequencing. Two novel mutations in SLC29A3 were found in the first two patients. In the third family a TCIRG1 C-terminal frameshift mutation in combination with a mutation at position +4 in intron 2 were detected. Our study adds two cases to the small group of individuals with SLC29A3 mutations diagnosed with dysosteosclerosis, and expands the phenotypic variability. The finding that intermediate autosomal recessive osteopetrosis due to TCIRG1 splice site mutations can also present with platyspondyly further increases the molecular heterogeneity of dysosteosclerosis-like sclerosing bone dysplasias.
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Affiliation(s)
- Antonia Howaldt
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | | | - Lisa-Marie Quell
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ayse Ozden
- Ataturk University Faculty of Medicine, Erzurum, Turkey
| | - Björn Fischer-Zirnsak
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Corinne Collet
- Service de Biochimie et Biologie Moléculaire, CHU Paris-GH St-Louis Lariboisière F. Widal - Hôpital Lariboisière, Paris, France
| | - Marie-Christine de Vernejoul
- INSERM U1132 BIOSCAR, Hôpital Lariboisière, 75010 Paris, France; University Paris Diderot, Sorbonne Paris Cité, Paris, France; Service de Rhumatologie, GH Saint-Louis Lariboisière Fernand Widal, Paris, France
| | - Hakan Doneray
- Ataturk University Faculty of Medicine, Erzurum, Turkey
| | - Hülya Kayserili
- Medical Genetics Department, Koç University School of Medicine (KUSOM), Istanbul, Turkey
| | - Uwe Kornak
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany; Max Planck Institute for Molecular Genetics, Berlin, Germany; Berlin-Brandenburg Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
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21
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Penna S, Capo V, Palagano E, Sobacchi C, Villa A. One Disease, Many Genes: Implications for the Treatment of Osteopetroses. Front Endocrinol (Lausanne) 2019; 10:85. [PMID: 30837952 PMCID: PMC6389615 DOI: 10.3389/fendo.2019.00085] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/31/2019] [Indexed: 11/23/2022] Open
Abstract
Osteopetrosis is a condition characterized by increased bone mass due to defects in osteoclast function or formation. In the last decades, the molecular dissection of osteopetrosis has unveiled a plethora of molecular players responsible for different forms of the disease, some of which present also primary neurodegeneration that severely limits the therapy. Hematopoietic stem cell transplantation can cure the majority of them when performed in the first months of life, highlighting the relevance of an early molecular diagnosis. However, clinical management of these patients is constrained by the severity of the disease and lack of a bone marrow niche that may delay immune reconstitution. Based on osteopetrosis genetic heterogeneity and disease severity, personalized therapies are required for patients that are not candidate to bone marrow transplantation. This review briefly describes the genetics of osteopetrosis, its clinical heterogeneity, current therapy and innovative approaches undergoing preclinical evaluation.
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Affiliation(s)
- Sara Penna
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), San Raffaele Hospital, Milan, Italy
- Translational and Molecular Medicine (DIMET), University of Milano-Bicocca, Monza, Italy
| | - Valentina Capo
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), San Raffaele Hospital, Milan, Italy
| | - Eleonora Palagano
- The National Research Council (CNR) Institute for Genetic and Biomedical Research (IRGB)- CNR-IRGB, Milan Unit, Milan, Italy
- Humanitas Research Hospital, Rozzano, Italy
| | - Cristina Sobacchi
- The National Research Council (CNR) Institute for Genetic and Biomedical Research (IRGB)- CNR-IRGB, Milan Unit, Milan, Italy
- Humanitas Research Hospital, Rozzano, Italy
| | - Anna Villa
- San Raffaele Telethon Institute for Gene Therapy (SR-Tiget), San Raffaele Hospital, Milan, Italy
- The National Research Council (CNR) Institute for Genetic and Biomedical Research (IRGB)- CNR-IRGB, Milan Unit, Milan, Italy
- *Correspondence: Anna Villa
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22
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Yang Y, Ye W, Guo J, Zhao L, Tu M, Zheng Y, Li L. CLCN7 and TCIRG1 mutations in a single family: Evidence for digenic inheritance of osteopetrosis. Mol Med Rep 2018; 19:595-600. [PMID: 30431110 DOI: 10.3892/mmr.2018.9648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 10/22/2018] [Indexed: 01/26/2023] Open
Abstract
Osteopetrosis is a monogenic condition with various inheritance patterns, including autosomal dominant, autosomal recessive and X‑linked. Several disease‑causing genes have been identified and three distinguished types of osteopetrosis have been reported. In the present study, a family with osteopetrosis was investigated. Two novel mutations in chloride voltage‑gated channel 7 (CLCN7) and T cell immune regulator 1 (TCIRG1) were identified by exome sequencing, Sanger sequencing and microsatellite marker analysis. The CLCN7 mutation occurred in amino acid R286, the same position as previously reported. The TCIRG1 mutation occurred on a splicing site of exon 15, thereby leading to a truncated transcript. These two mutations were undetected in 496 ethnic‑matched controls. To the best of our knowledge, this is the first report of human osteopetrosis involving digenic inheritance in a single family, which has important implications for decisions on clinical therapeutic regimen, prognosis evaluation and antenatal diagnosis.
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Affiliation(s)
- Yongjia Yang
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, Hunan 410007, P.R. China
| | - Weihua Ye
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, Hunan 410007, P.R. China
| | - Jihong Guo
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, Hunan 410007, P.R. China
| | - Liu Zhao
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, Hunan 410007, P.R. China
| | - Ming Tu
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, Hunan 410007, P.R. China
| | - Yu Zheng
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, Hunan 410007, P.R. China
| | - Liping Li
- The Laboratory of Genetics and Metabolism, Hunan Children's Research Institute (HCRI), Hunan Children's Hospital, University of South China, Changsha, Hunan 410007, P.R. China
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23
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Palagano E, Zuccarini G, Prontera P, Borgatti R, Stangoni G, Elisei S, Mantero S, Menale C, Forlino A, Uva P, Oppo M, Vezzoni P, Villa A, Merlo GR, Sobacchi C. Mutations in the Neuroblastoma Amplified Sequence gene in a family affected by Acrofrontofacionasal Dysostosis type 1. Bone 2018; 114:125-136. [PMID: 29929043 DOI: 10.1016/j.bone.2018.06.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 06/14/2018] [Accepted: 06/17/2018] [Indexed: 11/24/2022]
Abstract
Acrofrontofacionasal Dysostosis type 1 (AFFND1) is an extremely rare, autosomal recessive syndrome, comprising facial and skeletal abnormalities, short stature and intellectual disability. We analyzed an Indian family with two affected siblings by exome sequencing and identified a novel homozygous truncating mutation in the Neuroblastoma-Amplified Sequence (NBAS) gene in the patients' genome. Mutations in the NBAS gene have recently been associated with different phenotypes mainly involving skeletal formation, liver and cognitive development. The NBAS protein has been implicated in two key cellular processes, namely the non-sense mediated decay and the Golgi-to-Endoplasmic Reticulum retrograde traffic. Both functions were impaired in HEK293T cells overexpressing the truncated NBAS protein, as assessed by Real-Time PCR, Western blot analysis, co-immunoprecipitation, and immunofluorescence analysis. We examined the expression of NBAS protein in mouse embryos at various developmental stages by immunohistochemistry, and detected expression in developing chondrogenic and osteogenic structures of the skeleton as well as in the cortex, hippocampus and cerebellum, which is compatible with a role in bone and brain development. Functional genetics in the zebrafish model showed that depletion of endogenous z-nbas in fish embryos results in defective morphogenesis of chondrogenic cranial skeletal elements. Overall, our data point to a conserved function of NBAS in skeletal morphogenesis during development, support the hypothesis of a causative role of the mutated NBAS gene in the pathogenesis of AFFND1 and extend the spectrum of phenotypes associated with defects in this gene.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089 Rozzano, Italy; Department of Medical Biotechnologies and Translational Medicine, University of Milan, Via Vanvitelli 32, 20133 Milan, Italy
| | - Giulia Zuccarini
- Department Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, 10126 Turin, Italy
| | - Paolo Prontera
- Centro di Riferimento Regionale di Genetica Medica, Azienda Ospedaliera di Perugia, Piazzale Menghini 8/9, 06129 Perugia, Italy
| | - Renato Borgatti
- Child Neuropsychiatry and Neurorehabilitation Department, Scientific Institute Eugenio Medea, La Nostra Famiglia, Via Don Luigi Monza 20, 23842 Bosisio Parini, Italy
| | - Gabriela Stangoni
- Centro di Riferimento Regionale di Genetica Medica, Azienda Ospedaliera di Perugia, Piazzale Menghini 8/9, 06129 Perugia, Italy
| | - Sandro Elisei
- Istituto Serafico di Assisi, Viale Guglielmo Marconi 6, 06081 Assisi, Italy
| | - Stefano Mantero
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089 Rozzano, Italy; CNR-IRGB, Milan Unit, via Fantoli 16/15, 20138 Milan, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089 Rozzano, Italy; CNR-IRGB, Milan Unit, via Fantoli 16/15, 20138 Milan, Italy
| | - Antonella Forlino
- Department of Molecular Medicine, Unit of Biochemistry, University of Pavia, Via Taramelli 3/B, 27100 Pavia, Italy
| | - Paolo Uva
- CRS4, Science and Technology Park Polaris, Loc. Piscina Manna, 09010 Pula, Italy
| | - Manuela Oppo
- CRS4, Science and Technology Park Polaris, Loc. Piscina Manna, 09010 Pula, Italy
| | - Paolo Vezzoni
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089 Rozzano, Italy; CNR-IRGB, Milan Unit, via Fantoli 16/15, 20138 Milan, Italy
| | - Anna Villa
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089 Rozzano, Italy; CNR-IRGB, Milan Unit, via Fantoli 16/15, 20138 Milan, Italy
| | - Giorgio R Merlo
- Department Molecular Biotechnology and Health Sciences, University of Turin, Via Nizza 52, 10126 Turin, Italy
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089 Rozzano, Italy; CNR-IRGB, Milan Unit, via Fantoli 16/15, 20138 Milan, Italy.
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24
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Abstract
PURPOSE OF REVIEW The term osteopetrosis refers to a group of rare skeletal diseases sharing the hallmark of a generalized increase in bone density owing to a defect in bone resorption. Osteopetrosis is clinically and genetically heterogeneous, and a precise molecular classification is relevant for prognosis and treatment. Here, we review recent data on the pathogenesis of this disorder. RECENT FINDINGS Novel mutations in known genes as well as defects in new genes have been recently reported, further expanding the spectrum of molecular defects leading to osteopetrosis. Exploitation of next-generation sequencing tools is ever spreading, facilitating differential diagnosis. Some complex phenotypes in which osteopetrosis is accompanied by additional clinical features have received a molecular classification, also involving new genes. Moreover, novel types of mutations have been recognized, which for their nature or genomic location are at high risk being neglected. Yet, the causative mutation is unknown in some patients, indicating that the genetics of osteopetrosis still deserves intense research efforts.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Milan Unit, CNR-IRGB, Milan, Italy
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy.
- Milan Unit, CNR-IRGB, Milan, Italy.
| | - Anna Villa
- Humanitas Clinical and Research Institute, via Manzoni 113, 20089, Rozzano, MI, Italy
- Milan Unit, CNR-IRGB, Milan, Italy
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25
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Ajmal M, Mir A, Wahid S, Khor CC, Foo JN, Siddiqi S, Kauser M, Malik SA, Nasir M. Identification and in silico characterization of a novel p.P208PfsX1 mutation in V-ATPase a3 subunit associated with autosomal recessive osteopetrosis in a Pakistani family. BMC MEDICAL GENETICS 2017; 18:148. [PMID: 29237407 PMCID: PMC5729456 DOI: 10.1186/s12881-017-0506-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 11/29/2017] [Indexed: 11/15/2022]
Abstract
Background Osteopetrosis is a rare inherited bone disorder mainly described as an increased bone density caused by defective osteoclastic bone resorption. To date, genetic variants of eleven genes have been reported so far to be associated with different types of osteopetrosis. However, malignant infantile osteopetrosis, a lethal form of the disease, is mostly (50%) caused by mutation(s) in TCIRG1 gene. In this study, we investigated a consanguineous Pakistani family clinically and genetically to elucidate underlying molecular basis of the infantile osteopetrosis. Methods DNA samples from five family members were subjected to SNP-array based whole genome homozygosity mapping. Data was analyzed and potentially pathogenic mutation was identified by Sanger sequencing of two affected as well as three phenotypically healthy individuals in the family. The significance of identified pathogenic variation and its impact on protein structure and function was studied using various bioinformatics tools. Results DNA samples from five family members were subjected to genome-wide SNP array genotyping and homozygosity mapping which identified ~4 Mb region on chr11 harboring the TCIRG1 gene. Sanger sequencing unveiled a novel homozygous deletion c. 624delC in exon 6 of the TCIRG1 gene encodes a3 subunit of V-ATPase complex. The identified deletion resulted in a frame shift producing a truncated protein of 208 aa. In silico analysis of premature termination of the a3 subunit of V-ATPase complex revealed deleterious effects on the protein structure, predicting impaired or complete loss of V-ATPase function causing infantile osteopetrosis. Conclusions Since a3 subunit of V-ATPase complex plays a crucial role in bone resorption process, structurally abnormal a3 subunit might have adversely affected bone resorption process, leading to infantile osteopetrosis in Pakistani family. Therefore, the present study not only expands the genotypic spectrum of osteopetrosis but also improve understandings of the role of V-ATPase a3 subunit in bone resorption process. Moreover, our findings should help in genetic counseling and provide further insight into the disease pathogenesis and potential targeted therapy. Electronic supplementary material The online version of this article (10.1186/s12881-017-0506-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Muhammad Ajmal
- Institute of Biomedical and Genetic Engineering, 24-Mauve area, G-9/1, Islamabad, 44000, Pakistan
| | - Asif Mir
- Department of Biotechnology, International Islamic university, Islamabad, Pakistan
| | - Sughra Wahid
- KRL General Hospital, Pediatric Department 24-Mauve area, G-9/1, Islamabad, 44000, Pakistan
| | - Chiea Chuen Khor
- Human Genetics, Genome Institute of Singapore, A*STAR, Singapore, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jia Nee Foo
- Human Genetics, Genome Institute of Singapore, A*STAR, Singapore, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Saima Siddiqi
- Institute of Biomedical and Genetic Engineering, 24-Mauve area, G-9/1, Islamabad, 44000, Pakistan
| | - Mehran Kauser
- Institute of Biomedical and Genetic Engineering, 24-Mauve area, G-9/1, Islamabad, 44000, Pakistan
| | - Salman Akbar Malik
- Department of Biochemistry, Quaid-i-Azam University, Islamabad, 44000, Pakistan
| | - Muhammad Nasir
- Institute of Biomedical and Genetic Engineering, 24-Mauve area, G-9/1, Islamabad, 44000, Pakistan.
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26
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Zhang XY, He JW, Fu WZ, Wang C, Zhang ZL. Novel mutations of TCIRG1 cause a malignant and mild phenotype of autosomal recessive osteopetrosis (ARO) in four Chinese families. Acta Pharmacol Sin 2017; 38:1456-1465. [PMID: 28816234 DOI: 10.1038/aps.2017.108] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/11/2017] [Indexed: 01/04/2023] Open
Abstract
Human autosomal recessive osteopetrosis (ARO), also known as infantile malignant osteopetrosis, is a rare genetic bone disorder that often causes death. Mutations in T-cell immune regulator 1 (TCIRG1) are a frequent cause of human ARO. Six additional genes (TNFSF11, TNFRSF11A, CLCN7, OSTM1, SNX10, PLEKHM1) were also found to be associated with human ARO. In order to expand the mutation spectrum and clinical diversity for a better understanding of the ARO phenotype and to further investigate the clinical characteristics of benign subjects with ARO, we here report five individuals with ARO from four unrelated Chinese families. X-ray examination was conducted and bone turnover markers were assayed. The gene of T-cell immune regulator 1 (TCIRG1) was screened and analyzed. Monocyte-induced osteoclasts were prepared and their resorption ability was studied in vitro. We identified five novel mutations (c.66delC, c.1020+1_1020+5dup, c.2181C>A, c.2236+6T>G, c.692delA) in these patients. Four patients displayed a malignant phenotype, three of them died, and one who received bone marrow transplantation survived. The remaining one, a 24-year-old male from a consanguineous family, was diagnosed based on radiological findings but presented no neurological or hematological defects. He was homozygous for c.2236+6T>G in intron 18; this mutation influenced the splicing process. An in vitro functional study of this novel splicing defect showed no resorption pits on dentine slices. TCIRG1-dependent osteopetrosis with a mild clinical course was observed for the first time in Chinese population. The present findings add to the wide range of phenotypes of Chinese patients with TCIRG1-dependent ARO and enrich the database of TCIRG1 mutations.
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27
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Stattin EL, Henning P, Klar J, McDermott E, Stecksen-Blicks C, Sandström PE, Kellgren TG, Rydén P, Hallmans G, Lönnerholm T, Ameur A, Helfrich MH, Coxon FP, Dahl N, Wikström J, Lerner UH. SNX10 gene mutation leading to osteopetrosis with dysfunctional osteoclasts. Sci Rep 2017; 7:3012. [PMID: 28592808 PMCID: PMC5462793 DOI: 10.1038/s41598-017-02533-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 04/12/2017] [Indexed: 12/21/2022] Open
Abstract
Autosomal recessive osteopetrosis (ARO) is a heterogeneous disorder, characterized by defective osteoclastic resorption of bone that results in increased bone density. We have studied nine individuals with an intermediate form of ARO, from the county of Västerbotten in Northern Sweden. All afflicted individuals had an onset in early infancy with optic atrophy, and in four patients anemia was present at diagnosis. Tonsillar herniation, foramen magnum stenosis, and severe osteomyelitis of the jaw were common clinical features. Whole exome sequencing, verified by Sanger sequencing, identified a splice site mutation c.212 + 1 G > T in the SNX10 gene encoding sorting nexin 10. Sequence analysis of the SNX10 transcript in patients revealed activation of a cryptic splice site in intron 4 resulting in a frame shift and a premature stop (p.S66Nfs * 15). Haplotype analysis showed that all cases originated from a single mutational event, and the age of the mutation was estimated to be approximately 950 years. Functional analysis of osteoclast progenitors isolated from peripheral blood of patients revealed that stimulation with receptor activator of nuclear factor kappa-B ligand (RANKL) resulted in a robust formation of large, multinucleated osteoclasts which generated sealing zones; however these osteoclasts exhibited defective ruffled borders and were unable to resorb bone in vitro.
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Affiliation(s)
- Eva-Lena Stattin
- Department of Medical Biosciences, Medical and Clinical Genetics, Umeå University, 901 87, Umeå, Sweden. .,Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden.
| | - Petra Henning
- Centre for Bone and Arthritis Research, Department of internal medicine and clinical nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30, Gothenburg, Sweden.
| | - Joakim Klar
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden
| | - Emma McDermott
- Arthritis and Musculoskeletal Medicine Programme, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Christina Stecksen-Blicks
- Pediatric Dentistry, Department of Odontology, Faculty of Medicine, Umeå University, 901 87, Umeå, Sweden
| | | | - Therese G Kellgren
- Department of Mathematics and Mathematical Statistics, Computational Life science Cluster (CLiC), Umeå University, 901 87, Umeå, Sweden
| | - Patrik Rydén
- Department of Mathematics and Mathematical Statistics, Computational Life science Cluster (CLiC), Umeå University, 901 87, Umeå, Sweden
| | - Göran Hallmans
- Department of Biobank Research, Umeå University, 901 87, Umeå, Sweden
| | - Torsten Lönnerholm
- Department of Surgical Sciences, Radiology, Uppsala University, 751 85, Uppsala, Sweden
| | - Adam Ameur
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden
| | - Miep H Helfrich
- Arthritis and Musculoskeletal Medicine Programme, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Fraser P Coxon
- Arthritis and Musculoskeletal Medicine Programme, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Niklas Dahl
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, 751 85, Uppsala, Sweden
| | - Johan Wikström
- Department of Surgical Sciences, Radiology, Uppsala University, 751 85, Uppsala, Sweden
| | - Ulf H Lerner
- Centre for Bone and Arthritis Research, Department of internal medicine and clinical nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, 405 30, Gothenburg, Sweden.,Molecular Periodontology, Department of Odontology, Faculty of Medicine, Umeå University, 901 87, Umeå, Sweden
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28
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Deep intronic mutations and human disease. Hum Genet 2017; 136:1093-1111. [DOI: 10.1007/s00439-017-1809-4] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/05/2017] [Indexed: 12/22/2022]
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29
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Papachristou NI, Blair HC, Kypreos KE, Papachristou DJ. High-density lipoprotein (HDL) metabolism and bone mass. J Endocrinol 2017; 233:R95-R107. [PMID: 28314771 PMCID: PMC5598779 DOI: 10.1530/joe-16-0657] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 03/17/2017] [Indexed: 02/06/2023]
Abstract
It is well appreciated that high-density lipoprotein (HDL) and bone physiology and pathology are tightly linked. Studies, primarily in mouse models, have shown that dysfunctional and/or disturbed HDL can affect bone mass through many different ways. Specifically, reduced HDL levels have been associated with the development of an inflammatory microenvironment that affects the differentiation and function of osteoblasts. In addition, perturbation in metabolic pathways of HDL favors adipoblastic differentiation and restrains osteoblastic differentiation through, among others, the modification of specific bone-related chemokines and signaling cascades. Increased bone marrow adiposity also deteriorates bone osteoblastic function and thus bone synthesis, leading to reduced bone mass. In this review, we present the current knowledge and the future directions with regard to the HDL-bone mass connection. Unraveling the molecular phenomena that underline this connection will promote the deeper understanding of the pathophysiology of bone-related pathologies, such as osteoporosis or bone metastasis, and pave the way toward the development of novel and more effective therapies against these conditions.
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Affiliation(s)
- Nicholaos I Papachristou
- Department of Anatomy-Histology-EmbryologyUnit of Bone and Soft Tissue Studies, University of Patras Medical School, Patras, Greece
| | - Harry C Blair
- Department of PathologyUniversity of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Pittsburgh VA Medical CenterPittsburgh, Pennsylvania, USA
| | - Kyriakos E Kypreos
- Department of PharmacologyUniversity of Patras Medical School, Patras, Greece
| | - Dionysios J Papachristou
- Department of Anatomy-Histology-EmbryologyUnit of Bone and Soft Tissue Studies, University of Patras Medical School, Patras, Greece
- Department of PathologyUniversity of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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30
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Palagano E, Slatter MA, Uva P, Menale C, Villa A, Abinun M, Sobacchi C. Hematopoietic stem cell transplantation corrects osteopetrosis in a child carrying a novel homozygous mutation in the FERMT3 gene. Bone 2017; 97:126-129. [PMID: 28095295 DOI: 10.1016/j.bone.2017.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/22/2016] [Accepted: 01/13/2017] [Indexed: 12/14/2022]
Abstract
Osteopetrosis (OPT) is a rare skeletal disorder with phenotypic and genotypic heterogeneity: a variety of clinical features besides the bony defect may be present, and at least ten different genes are known to be involved in the disease pathogenesis. In the framework of this heterogeneity, we report the clinical description of a neonate, first child of consanguineous parents, who had osteoclast-rich osteopetrosis and bone marrow failure in early life, but no other usual classical features of infantile malignant OPT, such as visual or hearing impairments. Because of the severe presentation at birth, the patient received Hematopoietic Stem Cell Transplantation (HSCT) at 2months of age with successful outcome. Post-HSCT genetic investigation by means of exome sequencing identified a novel homozygous mutation in the Fermitin Family Member 3 (FERMT3) gene, which was predicted to disrupt the functionality of its protein product kindlin 3. Our report provides information relevant to physicians for recognizing patients with one of the rarest forms of infantile malignant OPT, and clearly demonstrates that HSCT cures kindlin 3 deficiency with severe phenotype.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, Rozzano, Italy; Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy
| | - Mary A Slatter
- Bone Marrow Transplantation Unit, Great North Children's Hospital, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Primary Immunodeficiency Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Paolo Uva
- CRS4, Science and Technology Park Polaris, Pula, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, Rozzano, Italy; CNR-IRGB, Milan Unit, Milan, Italy
| | - Anna Villa
- Humanitas Clinical and Research Institute, Rozzano, Italy; CNR-IRGB, Milan Unit, Milan, Italy
| | - Mario Abinun
- Bone Marrow Transplantation Unit, Great North Children's Hospital, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK; Primary Immunodeficiency Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, Rozzano, Italy; CNR-IRGB, Milan Unit, Milan, Italy
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31
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Palagano E, Susani L, Menale C, Ramenghi U, Berger M, Uva P, Oppo M, Vezzoni P, Villa A, Sobacchi C. Synonymous Mutations Add a Layer of Complexity in the Diagnosis of Human Osteopetrosis. J Bone Miner Res 2017; 32:99-105. [PMID: 27468155 DOI: 10.1002/jbmr.2929] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/25/2016] [Accepted: 07/27/2016] [Indexed: 11/08/2022]
Abstract
Autosomal recessive osteopetroses (AROs) are rare, genetically heterogeneous skeletal diseases with increased bone density that are often lethal if left untreated. A precise molecular classification is relevant for the patient's management, because in some subgroups hematopoietic stem cell transplantation (HSCT), which is the only curative therapy, is contraindicated. In two unrelated ARO patients, the molecular analysis revealed the presence of a synonymous variant in known ARO genes, namely in the TCIRG1 gene in one patient and in the CLCN7 in the other patient, predicted to impact on the splicing process. In the latter case, sequencing of the transcript confirmed the splicing defect, whereas in the former, for whom an RNA sample was not available, the defect was reconstructed in vitro by the minigene technology. These results strongly suggest that these synonymous changes were responsible for the disease in our patients. Our findings are novel with respect to ARO and add to the few reports in literature dealing with different diseases, underlining the importance of cDNA analysis for the correct assessment of exonic changes, even when exome sequencing is performed. In particular, we highlight the possibility that at least in some cases ARO is due to synonymous changes, erroneously considered clinically silent, in the genes already described in literature, and suggest carefully reevaluating the sequencing results of these genes when mutations are not found at a first analysis. In addition, with respect to the CLCN7 gene, we suggest that synonymous variants might also contribute to the large spectrum of severity typical of CLCN7-dependent osteopetrosis through more subtle, but not negligible, effects on protein availability and functionality. © 2016 American Society for Bone and Mineral Research.
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Affiliation(s)
- Eleonora Palagano
- Humanitas Clinical and Research Institute, Rozzano, Italy.,Department of Medical Biotechnologies and Translational Medicine, University of Milan, Milan, Italy
| | - Lucia Susani
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Ciro Menale
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Ugo Ramenghi
- Department of Public Health and Pediatric Sciences, University of Turin, Turin, Italy
| | - Massimo Berger
- Pediatric Onco-Hematology and Stem Cell Transplant Division, Regina Margherita Children Hospital, City of Health and Science, Turin, Italy
| | - Paolo Uva
- CRS4, Science and Technology Park Polaris, Pula, Italy
| | - Manuela Oppo
- CRS4, Science and Technology Park Polaris, Pula, Italy.,Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Paolo Vezzoni
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Anna Villa
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
| | - Cristina Sobacchi
- Humanitas Clinical and Research Institute, Rozzano, Italy.,National Research Council-Institute of Genetics and Biomedical Research (CNR-IRGB), Milan Unit, Milan, Italy
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Thudium CS, Moscatelli I, Löfvall H, Kertész Z, Montano C, Bjurström CF, Karsdal MA, Schulz A, Richter J, Henriksen K. Regulation and Function of Lentiviral Vector-Mediated TCIRG1 Expression in Osteoclasts from Patients with Infantile Malignant Osteopetrosis: Implications for Gene Therapy. Calcif Tissue Int 2016; 99:638-648. [PMID: 27541021 DOI: 10.1007/s00223-016-0187-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 08/08/2016] [Indexed: 10/21/2022]
Abstract
Infantile malignant osteopetrosis (IMO) is a rare, recessive disorder characterized by increased bone mass caused by dysfunctional osteoclasts. The disease is most often caused by mutations in the TCIRG1 gene encoding a subunit of the V-ATPase involved in the osteoclasts capacity to resorb bone. We previously showed that osteoclast function can be restored by lentiviral vector-mediated expression of TCIRG1, but the exact threshold for restoration of resorption as well as the cellular response to vector-mediated TCIRG1 expression is unknown. Here we show that expression of TCIRG1 protein from a bicistronic TCIRG1/GFP lentiviral vector was only observed in mature osteoclasts, and not in their precursors or macrophages, in contrast to GFP expression, which was observed under all conditions. Thus, vector-mediated TCIRG1 expression appears to be post-transcriptionally regulated, preventing overexpression and/or ectopic expression and ensuring protein expression similar to that of wild-type osteoclasts. Codon optimization of TCIRG1 led to increased expression of mRNA but lower levels of protein and functional rescue. When assessing the functional rescue threshold in vitro, addition of 30 % CB CD34+ cells to IMO CD34+ patient cells was sufficient to completely normalize resorptive function after osteoclast differentiation. From both an efficacy and a safety perspective, these findings will clearly be of benefit during further development of gene therapy for osteopetrosis.
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Affiliation(s)
| | - Ilana Moscatelli
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, BMC A12, 221 84, Lund, Sweden
| | - Henrik Löfvall
- Nordic Bioscience, Herlev, Denmark
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, BMC A12, 221 84, Lund, Sweden
| | - Zsuzsanna Kertész
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, BMC A12, 221 84, Lund, Sweden
| | - Carmen Montano
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, BMC A12, 221 84, Lund, Sweden
| | - Carmen Flores Bjurström
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, BMC A12, 221 84, Lund, Sweden
| | | | - Ansgar Schulz
- Department of Pediatrics and Adolescent Medicine, University Medical Center, Ulm, Germany
| | - Johan Richter
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology, BMC A12, 221 84, Lund, Sweden.
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Simanovsky N, Rozovsky K, Hiller N, Weintraub M, Stepensky P. Extending the Spectrum of Radiological Findings in Patients With Severe Osteopetrosis and Different Genetic Backgrounds. Pediatr Blood Cancer 2016; 63:1222-6. [PMID: 26970326 DOI: 10.1002/pbc.25952] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Revised: 01/12/2016] [Accepted: 01/25/2016] [Indexed: 11/06/2022]
Abstract
PURPOSE To evaluate radiological findings in a cohort of 22 patients with infantile malignant osteopetrosis in order to establish the correlation between radiological findings and different genetic backgrounds. MATERIALS AND METHODS Clinical files, genetic analysis results, and radiological examinations of children treated for osteopetrosis with bone marrow transplantation in a referral center in the last 5 years were retrospectively evaluated. The study received institutional review board (IRB) approval. RESULTS Twenty-two patients were included in the study: 18 males, four females, ages 1 month-9 years 10 months, and the median age was 11 months (mean 23 months). There were 12 patients with different mutations in the TCIRG1 gene, five with mutations in the SNX10 gene, four children harbored RANK mutations, and one patient had a CLCN7 mutation. We noted more severe radiological findings in patients with TCIRG1 and RANK mutations, including fractures, osteopetrorickets, hydrocephalus, and hepatomegaly. Varus deformity of the femoral neck was seen exclusively in patients with a TCIRG1 mutation. CONCLUSIONS The variable genetic spectrum of osteopetrosis is associated with a variable radiological presentation. These correlations may be helpful for priorities in genetic analysis.
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Affiliation(s)
- Natalia Simanovsky
- Department of Medical Imaging, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Katya Rozovsky
- Department of Medical Imaging, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Nurith Hiller
- Department of Medical Imaging, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Michael Weintraub
- Department of Pediatric Hematology-Oncology and Bone Marrow Transplantation, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Polina Stepensky
- Department of Pediatric Hematology-Oncology and Bone Marrow Transplantation, Hadassah Hebrew University Medical Center, Jerusalem, Israel
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Deng H, He D, Rong P, Xu H, Yuan L, Li L, Lu Q, Guo Y. Novel CLCN7 mutation identified in a Han Chinese family with autosomal dominant osteopetrosis-2. Mol Pain 2016; 12:12/0/1744806916652628. [PMID: 27325559 PMCID: PMC4955969 DOI: 10.1177/1744806916652628] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/06/2016] [Indexed: 12/25/2022] Open
Abstract
Osteopetrosis is a heritable bone condition featuring increased bone density due to defective osteoclastic bone resorption. Exome sequencing and Sanger sequencing were conducted in Han Chinese family members, some of whom had typical osteopetrosis, and a novel missense variant c.2350A>T (p.R784W) in the chloride channel 7 gene (CLCN7) was identified. This variant cosegregated with the disorder in the family but was not observed in 800 controls. The data indicate that exome sequencing is a powerful and effective molecular diagnostic tool for detecting mutations in osteopetrosis, which is a genetically and clinically heterogeneous disorder. This discovery broadens the CLCN7 gene mutation spectrum and has important implications for clinical therapeutic regimen decisions, prognosis evaluations, and antenatal diagnoses.
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Affiliation(s)
- Hao Deng
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
- Hao Deng, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, Hunan 410013, China. Yi Guo, Department of Medical Information, Information Security and Big Data Research Institute, Central South University, 172 Tongzipo Road, Changsha, Hunan 410013, China.
| | - Dan He
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Pengfei Rong
- Department of Radiology, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongbo Xu
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Lamei Yuan
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Liu Li
- Department of Pediatrics, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Qian Lu
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Yi Guo
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China
- Department of Medical Information, Information Security and Big Data Research Institute, Central South University, Changsha, China
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CADD score has limited clinical validity for the identification of pathogenic variants in noncoding regions in a hereditary cancer panel. Genet Med 2016; 18:1269-1275. [PMID: 27148939 PMCID: PMC5097698 DOI: 10.1038/gim.2016.44] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/24/2016] [Indexed: 12/18/2022] Open
Abstract
PURPOSE Several in silico tools have been shown to have reasonable research sensitivity and specificity for classifying sequence variants in coding regions. The recently-developed Combined Annotation Dependent Depletion (CADD) method generates predictive scores for single nucleotide variants (SNVs) in all areas of the genome, including non-coding regions. We sought to determine the clinical validity of non-coding variant CADD scores. METHODS We evaluated 12,391 unique SNVs in 624 patient samples submitted for germline mutation testing in a cancer-related gene panel. We compared the distributions of CADD scores of rare SNVs, common SNVs in our patient population, and the null distribution of all possible SNVs stratifying by genomic region. RESULTS The median CADD scores of intronic and nonsynonymous variants were significantly different between rare and common SNVs (p<0.0001). Despite these different distributions, no individual variants could be identified as plausibly causative among rare intronic variants with the highest scores. The ROC AUC for non-coding variants is modest, and the positive predictive value of CADD for intronic variants in panel testing was found to be 0.088. CONCLUSION Focused in-silico scoring systems with much higher predictive value will be necessary for clinical genomic applications.
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Stepensky P, Keller B, Shamriz O, NaserEddin A, Rumman N, Weintraub M, Warnatz K, Elpeleg O, Barak Y. Deep intronic mis-splicing mutation in JAK3 gene underlies T−B+NK− severe combined immunodeficiency phenotype. Clin Immunol 2016; 163:91-5. [DOI: 10.1016/j.clim.2016.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/02/2016] [Accepted: 01/02/2016] [Indexed: 12/22/2022]
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Larrouture QC, Nelson DJ, Robinson LJ, Liu L, Tourkova I, Schlesinger PH, Blair HC. Chloride-hydrogen antiporters ClC-3 and ClC-5 drive osteoblast mineralization and regulate fine-structure bone patterning in vitro. Physiol Rep 2015; 3:3/11/e12607. [PMID: 26603451 PMCID: PMC4673636 DOI: 10.14814/phy2.12607] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 10/09/2015] [Indexed: 12/03/2022] Open
Abstract
Osteoblasts form an epithelium-like layer with tight junctions separating bone matrix from extracellular fluid. During mineral deposition, calcium and phosphate precipitation in hydroxyapatite liberates 0.8 mole of H+ per mole Ca+2. Thus, acid export is needed for mineral formation. We examined ion transport supporting osteoblast vectorial mineral deposition. Previously we established that Na/H exchangers 1 and 6 are highly expressed at secretory osteoblast basolateral surfaces and neutralize massive acid loads. The Na/H exchanger regulatory factor-1 (NHERF1), a pdz-organizing protein, occurs at mineralizing osteoblast basolateral surfaces. We hypothesized that high-capacity proton transport from matrix into osteoblast cytosol must exist to support acid transcytosis for mineral deposition. Gene screening in mineralizing osteoblasts showed dramatic expression of chloride–proton antiporters ClC-3 and ClC-5. Antibody localization showed that ClC-3 and ClC-5 occur at the apical secretory surface facing the bone matrix and in membranes of buried osteocytes. Surprisingly, the Clcn3−/− mouse has only mildly disordered mineralization. However, Clcn3−/− osteoblasts have large compensatory increases in ClC-5 expression. Clcn3−/− osteoblasts mineralize in vitro in a striking and novel trabecular pattern; wild-type osteoblasts form bone nodules. In mesenchymal stem cells from Clcn3−/− mice, lentiviral ClC-5 shRNA created Clcn3−/−, ClC-5 knockdown cells, validated by western blot and PCR. Osteoblasts from these cells produced no mineral under conditions where wild-type or Clcn3−/− cells mineralize well. We conclude that regulated acid export, mediated by chloride–proton exchange, is essential to drive normal bone mineralization, and that CLC transporters also regulate fine patterning of bone.
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Affiliation(s)
| | - Deborah J Nelson
- Department of Neurobiology, Pharmacology & Physiology, University of Chicago, Chicago, Illinois
| | - Lisa J Robinson
- Departments of Pathology and of Microbiology, Immunology & Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia
| | - Li Liu
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Irina Tourkova
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Paul H Schlesinger
- Department of Cell Biology, Washington University, Saint Louis, Missouri
| | - Harry C Blair
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania Veteran's Affairs Medical Center, Pittsburgh, Pennsylvania
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