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Zhao T, Xu S, Liu S, Xu J, Zhang X, Zhan Y. Fahr's disease linked to a novel mutation in MYORG variants manifesting as paroxysmal limb stiffness and dysarthria: Case report and literature review. Mol Genet Genomic Med 2023; 11:e2276. [PMID: 37680026 PMCID: PMC10724521 DOI: 10.1002/mgg3.2276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 07/24/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND Primary familial brain calcification (PFBC) is a rare hereditary neurodegenerative disorder associated with the MYORG gene; however, the clinical and radiological characteristics of MYORG-PFBC remain unclear. METHODS We present relevant medical data obtained from a patient affected by PFBC with a novel MYORG variant and conducted a mutational analysis of MYORG in her family members. We reviewed all reported PFBC cases with biallelic MYORG mutations until April 1, 2023, and summarized the associated clinical and radiological features and mutation sites. RESULTS The patient (22-year-old woman) exhibited paroxysmal limb stiffness and dysarthria for 3 years. Computed tomography revealed calcifications in the paraventricular white matter, basal ganglia, thalamus, and cerebellum. Whole-exome sequencing revealed a novel homozygous frameshift variant (c.743delG: p.G248Afs*32) in exon 2 of the MYORG gene (NM_020702.5). To date, 62 families and 64 mutation sites have been reported. Among the reported biallelic MYORG mutations, 57% were homozygous and 43% were compound heterozygous. Individuals with biallelic MYORG mutations experience more severe brain calcification with approximately 100% clinical penetrance. Ten single heterozygous mutation sites are associated with significant brain calcifications. CONCLUSION All patients with primary brain calcification, particularly younger patients without a family history of the disease, should be screened for MYORG mutations.
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Affiliation(s)
- Tianxue Zhao
- Department of Endocrinology, Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouChina
| | - Shaokun Xu
- Department of GeriatricsZhejiang Provincial People's HospitalHangzhouChina
| | - Siyue Liu
- Department of Endocrinology, Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouChina
| | - Juan Xu
- Department of Endocrinology, Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouChina
| | - Xianfeng Zhang
- Department of Endocrinology, Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouChina
| | - Yuhong Zhan
- Department of Endocrinology, Affiliated Hangzhou First People's HospitalZhejiang University School of MedicineHangzhouChina
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Ikegaya M, Park EY, Miyazaki T. Structure-function analysis of bacterial GH31 α-galactosidases specific for α-(1→4)-galactobiose. FEBS J 2023; 290:4984-4998. [PMID: 37438884 DOI: 10.1111/febs.16904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/21/2023] [Accepted: 07/10/2023] [Indexed: 07/14/2023]
Abstract
Glycoside hydrolase family 31 (GH31) contains α-glycoside hydrolases with different substrate specificities involved in various physiological functions. This family has recently been classified into 20 subfamilies using sequence similarity networks. An α-galactosidase from the gut bacterium Bacteroides salyersiae (BsGH31_19, which belongs to GH31 subfamily 19) was reported to have hydrolytic activity against the synthetic substrate p- nitrophenyl α-galactopyranoside, but its natural substrate remained unknown. BsGH31_19 shares low sequence identity (around 20%) with other reported GH31 α-galactosidases, PsGal31A from Pseudopedobacter saltans and human myogenesis-regulating glycosidase (MYORG), and was expected to have distinct specificity. Here, we characterized BsGH31_19 and its ortholog from a soil Bacteroidota bacterium, Flavihumibacter petaseus (FpGH31_19), and demonstrated that they showed high substrate specificity against α-(1→4)-linkages in α-(1→4)-galactobiose and globotriose [α-Gal-(1→4)-β-Gal-(1→4)-Glc], unlike PsGal31A and MYORG. The crystallographic analyses of BsGH31_19 and FpGH31_19 showed that their overall structures resemble those of MYORG and form a dimer with an interface different from that of PsGal31A and MYORG dimers. The structures of FpGH31_19 complexed with d-galactose and α-(1→4)-galactobiose revealed that amino acid residues that recognize a galactose residue at subsite +1 are not conserved between FpGH31_19 and BsGH31_19. The tryptophan (Trp153) that recognizes galactose at subsite -1 is homologous to the tryptophan residues in MYORG and α-galactosidases belonging to GH27, GH36, and GH97, but not in the bacterial GH31 member PsGal31A. Our results provide structural insights into molecular diversity and evolutionary relationships in the GH31 α-galactosidase subfamilies and the other α-galactosidase families.
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Affiliation(s)
- Marina Ikegaya
- Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, Japan
| | - Enoch Y Park
- Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, Japan
- Research Institute of Green Science and Technology, Shizuoka University, Japan
| | - Takatsugu Miyazaki
- Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, Japan
- Research Institute of Green Science and Technology, Shizuoka University, Japan
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Monfrini E, Arienti F, Rinchetti P, Lotti F, Riboldi GM. Brain Calcifications: Genetic, Molecular, and Clinical Aspects. Int J Mol Sci 2023; 24:ijms24108995. [PMID: 37240341 DOI: 10.3390/ijms24108995] [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: 03/01/2023] [Revised: 04/21/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Many conditions can present with accumulation of calcium in the brain and manifest with a variety of neurological symptoms. Brain calcifications can be primary (idiopathic or genetic) or secondary to various pathological conditions (e.g., calcium-phosphate metabolism derangement, autoimmune disorders and infections, among others). A set of causative genes associated with primary familial brain calcification (PFBC) has now been identified, and include genes such as SLC20A2, PDGFB, PDGFRB, XPR1, MYORG, and JAM2. However, many more genes are known to be linked with complex syndromes characterized by brain calcifications and additional neurologic and systemic manifestations. Of note, many of these genes encode for proteins involved in cerebrovascular and blood-brain barrier functions, which both represent key anatomical structures related to these pathological phenomena. As a growing number of genes associated with brain calcifications is identified, pathways involved in these conditions are beginning to be understood. Our comprehensive review of the genetic, molecular, and clinical aspects of brain calcifications offers a framework for clinicians and researchers in the field.
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Affiliation(s)
- Edoardo Monfrini
- Dino Ferrari Center, Neuroscience Section, Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, 20122 Milan, Italy
| | - Federica Arienti
- Foundation IRCCS Ca' Granda Ospedale Maggiore Policlinico, Neurology Unit, 20122 Milan, Italy
| | - Paola Rinchetti
- Columbia University Irving Medical Center, Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology and Neurology, New York, NY 10032, USA
| | - Francesco Lotti
- Columbia University Irving Medical Center, Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology and Neurology, New York, NY 10032, USA
| | - Giulietta M Riboldi
- The Marlene and Paolo Fresco Institute for Parkinson's and Movement Disorders, Department of Neurology, NYU Langone Health, New York, NY 10017, USA
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Sadok SH, Borges-Medeiros RL, de Oliveira DF, Zatz M, de Oliveira JRM. Report of a young patient with brain calcifications with a novel homozygous MYORG variant. Gene 2023; 859:147213. [PMID: 36690225 DOI: 10.1016/j.gene.2023.147213] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/25/2022] [Accepted: 01/16/2023] [Indexed: 01/22/2023]
Abstract
Primary familial brain calcifications (PFBC) is characterized by bilateral and symmetrical deposition of inorganic phosphate, mainly in the basal ganglia, thalamus, cerebellum, and dentate nucleus. The symptoms resemble other neuropsychiatric conditions, such as Parkinsonism, dementia, migraine, and mood disorders. Pathogenic variants in six genes have been associated with this disorder, four linked to the autosomal dominant mode (SLC20A2, PDGFRB, PDGFB, and XPR1) and two linked to the recessive fashion (MYORG and JAM2). Herein, we report a young 24-year-old patient with a medical history of bilateral and symmetrical brain calcification and neuropsychiatric symptoms that include movement disturbances (chorea and dystonia), chronic migraine, unexplained tinnitus, and mood swings. After whole-exome sequencing, she was diagnosed with a novel homozygous MYORG variant (c.912_914del; p.(Ser305del)). In silico analysis showed that the variant is located on the extracellular domain of MYORG protein and is predicted to be disease-causing (likely pathogenic), implying that protein features might be affected. This study describes the second Brazilian case of MYORG PFBC-causative gene. Furthermore, it highlights the early age and onset of symptoms of the proband, especially in regard to movement disorders.
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Affiliation(s)
| | | | - Danyllo F de Oliveira
- Department of Genetics and Evolutionary Biology, Biosciences Institute, University of São Paulo, Brazil
| | - Mayana Zatz
- Department of Genetics and Evolutionary Biology, Biosciences Institute, University of São Paulo, Brazil
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Carecchio M, Mainardi M, Bonato G. The clinical and genetic spectrum of primary familial brain calcification. J Neurol 2023; 270:3270-3277. [PMID: 36862146 DOI: 10.1007/s00415-023-11650-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023]
Abstract
Primary familial brain calcification (PFBC), formerly known as Fahr's disease, is a rare neurodegenerative disease characterized by bilateral progressive calcification of the microvessels of the basal ganglia and other cerebral and cerebellar structures. PFBC is thought to be due to an altered function of the Neurovascular Unit (NVU), where abnormal calcium-phosphorus metabolism, functional and microanatomical alterations of pericytes and mitochondrial alterations cause a dysfunction of the blood-brain barrier (BBB) and the generation of an osteogenic environment with surrounding astrocyte activation and progressive neurodegeneration. Seven causative genes have been discovered so far, of which four with dominant (SLC20A2, PDGFB, PDGFRB, XPR1) and three with recessive inheritance (MYORG, JAM2, CMPK2). Clinical presentation ranges from asymptomatic subjects to movement disorders, cognitive decline and psychiatric disturbances alone or in various combinations. Radiological patterns of calcium deposition are similar in all known genetic forms, but central pontine calcification and cerebellar atrophy are highly suggestive of MYORG mutations and extensive cortical calcification has been associated with JAM2 mutations. Currently, no disease-modifying drugs or calcium-chelating agents are available and only symptomatic treatments can be offered.
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Affiliation(s)
- Miryam Carecchio
- Department of Neuroscience, University of Padua, Via Niccolò Giustiniani, 5, 35128, Padua, Italy.
| | - Michele Mainardi
- Department of Neuroscience, University of Padua, Via Niccolò Giustiniani, 5, 35128, Padua, Italy
| | - Giulia Bonato
- Department of Neuroscience, University of Padua, Via Niccolò Giustiniani, 5, 35128, Padua, Italy
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Arumapperuma T, Li J, Hornung B, Soler NM, Goddard-Borger ED, Terrapon N, Williams SJ. A subfamily classification to choreograph the diverse activities within glycoside hydrolase family 31. J Biol Chem 2023; 299:103038. [PMID: 36806678 PMCID: PMC10074150 DOI: 10.1016/j.jbc.2023.103038] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 02/18/2023] Open
Abstract
The Carbohydrate-Active Enzyme classification groups enzymes that breakdown, assemble, or decorate glycans into protein families based on sequence similarity. The glycoside hydrolases (GH) are arranged into over 170 enzyme families, with some being very large and exhibiting distinct activities/specificities towards diverse substrates. Family GH31 is a large family that contains more than 20,000 sequences with a wide taxonomic diversity. Less than 1% of GH31 members are biochemically characterized and exhibit many different activities that include glycosidases, lyases, and transglycosidases. This diversity of activities limits our ability to predict the activities and roles of GH31 family members in their host organism and our ability to exploit these enzymes for practical purposes. Here, we established a subfamily classification using sequence similarity networks that was further validated by a structural analysis. While sequence similarity networks provide a sequence-based separation, we obtained good segregation between activities among the subfamilies. Our subclassification consists of 20 subfamilies with sixteen subfamilies containing at least one characterized member and eleven subfamilies that are monofunctional based on the available data. We also report the biochemical characterization of a member of the large subfamily 2 (GH31_2) that lacked any characterized members: RaGH31 from Rhodoferax aquaticus is an α-glucosidase with activity on a range of disaccharides including sucrose, trehalose, maltose, and nigerose. Our subclassification provides improved predictive power for the vast majority of uncharacterized proteins in family GH31 and highlights the remaining sequence space that remains to be functionally explored.
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Affiliation(s)
- Thimali Arumapperuma
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute and University of Melbourne, Parkville, Victoria, Australia
| | - Jinling Li
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute and University of Melbourne, Parkville, Victoria, Australia
| | - Bastian Hornung
- AFMB, UMR 7257 CNRS Aix-Marseille Univ., USC 1408 INRAE, Marseille, France
| | - Niccolay Madiedo Soler
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Ethan D Goddard-Borger
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Nicolas Terrapon
- AFMB, UMR 7257 CNRS Aix-Marseille Univ., USC 1408 INRAE, Marseille, France
| | - Spencer J Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute and University of Melbourne, Parkville, Victoria, Australia.
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Zhang Y, Ren Y, Zhang Y, Li Y, Xu C, Peng Z, Jia Y, Qiao S, Zhang Z, Shi L. T-cell infiltration in the central nervous system and their association with brain calcification in Slc20a2-deficient mice. Front Mol Neurosci 2023; 16:1073723. [PMID: 36741925 PMCID: PMC9894888 DOI: 10.3389/fnmol.2023.1073723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/03/2023] [Indexed: 01/21/2023] Open
Abstract
Primary familial brain calcification (PFBC) is a rare neurodegenerative and neuropsychiatric disorder characterized by bilateral symmetric intracranial calcification along the microvessels or inside neuronal cells in the basal ganglia, thalamus, and cerebellum. Slc20a2 homozygous (HO) knockout mice are the most commonly used model to simulate the brain calcification phenotype observed in human patients. However, the cellular and molecular mechanisms related to brain calcification, particularly at the early stage much prior to the emergence of brain calcification, remain largely unknown. In this study, we quantified the central nervous system (CNS)-infiltrating T-cells of different age groups of Slc20a2-HO and matched wild type mice and found CD45+CD3+ T-cells to be significantly increased in the brain parenchyma, even in the pre-calcification stage of 1-month-old -HO mice. The accumulation of the CD3+ T-cells appeared to be associated with the severity of brain calcification. Further immunophenotyping revealed that the two main subtypes that had increased in the brain were CD3+ CD4- CD8- and CD3+ CD4+ T-cells. The expression of endothelial cell (EC) adhesion molecules increased, while that of tight and adherents junction proteins decreased, providing the molecular precondition for T-cell recruitment to ECs and paracellular migration into the brain. The fusion of lymphocytes and EC membranes and transcellular migration of CD3-related gold particles were captured, suggesting enhancement of transcytosis in the brain ECs. Exogenous fluorescent tracers and endogenous IgG and albumin leakage also revealed an impairment of transcellular pathway in the ECs. FTY720 significantly alleviated brain calcification, probably by reducing T-cell infiltration, modulating neuroinflammation and ossification process, and enhancing the autophagy and phagocytosis of CNS-resident immune cells. This study clearly demonstrated CNS-infiltrating T-cells to be associated with the progression of brain calcification. Impairment of blood-brain barrier (BBB) permeability, which was closely related to T-cell invasion into the CNS, could be explained by the BBB alterations of an increase in the paracellular and transcellular pathways of brain ECs. FTY720 was found to be a potential drug to protect patients from PFBC-related lesions in the future.
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Affiliation(s)
- Yi Zhang
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Medical Genetics, College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Yaqiong Ren
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yueni Zhang
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Medical Genetics, College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Ying Li
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Child and Adolescent Health, School of Public Health, Harbin Medical University, Harbin, China
| | - Chao Xu
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Pediatrics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Ziyue Peng
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Pediatrics, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Ying Jia
- Department of Medical Genetics, College of Basic Medical Sciences, Harbin Medical University, Harbin, China,Department of Child and Adolescent Health, School of Public Health, Harbin Medical University, Harbin, China
| | - Shupei Qiao
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Child and Adolescent Health, School of Public Health, Harbin Medical University, Harbin, China
| | - Zitong Zhang
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Medical Genetics, College of Basic Medical Sciences, Harbin Medical University, Harbin, China
| | - Lei Shi
- Human Molecular Genetics Group, NHC Key Laboratory of Molecular Probes and Targeted Diagnosis and Therapy, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, China,Department of Medical Genetics, College of Basic Medical Sciences, Harbin Medical University, Harbin, China,*Correspondence: Lei Shi,
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