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Margiotti K, Libotte F, Fabiani M, Mesoraca A, Giorlandino C. Digenic Origin of Difference of Sex Development in a Patient Harbouring DHX37 and MAMLD1 Variants. Case Rep Pediatr 2024; 2024:4896940. [PMID: 38962685 PMCID: PMC11221946 DOI: 10.1155/2024/4896940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 05/03/2024] [Accepted: 05/31/2024] [Indexed: 07/05/2024] Open
Abstract
Background The diagnostic process for identifying variations in sex development (DSD) remains challenging due to the limited availability of evidence pertaining to the association between phenotype and genotype. DSD incidence is reported as 2 in 10,000 births, and the etiology has been attributed to genetic causes. Case Presentation. The present study investigated genetic causes implicated in a case of a 15-year-old 46, XY patient, raised as a girl. Genetic analysis by clinical exome sequencing (CES) showed a digenic inheritance due to two known pathogenic mutations in the DHX37 gene and the MAMLD1 gene, while we excluded variants with pathogenic significance in 209 DSD-related genes. Conclusions Based on our literature review, this is the first case with the combined presence of pathogenic mutations in the MAMLD1 gene and DHX37 gene in a patient with gonadal dysgenesis.
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Affiliation(s)
- Katia Margiotti
- ALTAMEDICA, Human Genetics Lab, Viale Liegi 45, Rome 00198, Italy
| | | | - Marco Fabiani
- ALTAMEDICA, Human Genetics Lab, Viale Liegi 45, Rome 00198, Italy
| | - Alvaro Mesoraca
- ALTAMEDICA, Human Genetics Lab, Viale Liegi 45, Rome 00198, Italy
| | - Claudio Giorlandino
- ALTAMEDICA, Human Genetics Lab, Viale Liegi 45, Rome 00198, Italy
- ALTAMEDICA, Fetal-Maternal Medical Centre, Department of Prenatal Diagnosis, Viale Liegi 45, Rome 00198, Italy
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2
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Kušíková K, Šoltýsová A, Ficek A, Feichtinger RG, Mayr JA, Škopková M, Gašperíková D, Kolníková M, Ornig K, Kalev O, Weis S, Weis D. Prognostic Value of Genotype-Phenotype Correlations in X-Linked Myotubular Myopathy and the Use of the Face2Gene Application as an Effective Non-Invasive Diagnostic Tool. Genes (Basel) 2023; 14:2174. [PMID: 38136996 PMCID: PMC10742680 DOI: 10.3390/genes14122174] [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: 11/12/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
BACKGROUND X-linked myotubular myopathy (XLMTM) is a rare congenital myopathy resulting from dysfunction of the protein myotubularin encoded by the MTM1 gene. XLMTM has a high neonatal and infantile mortality rate due to a severe myopathic phenotype and respiratory failure. However, in a minority of XLMTM cases, patients present with milder phenotypes and achieve ambulation and adulthood. Notable facial dysmorphia is also present. METHODS We investigated the genotype-phenotype correlations in newly diagnosed XLMTM patients in a patients' cohort (previously published data plus three novel variants, n = 414). Based on the facial gestalt difference between XLMTM patients and unaffected controls, we investigated the use of the Face2Gene application. RESULTS Significant associations between severe phenotype and truncating variants (p < 0.001), frameshift variants (p < 0.001), nonsense variants (p = 0.006), and in/del variants (p = 0.036) were present. Missense variants were significantly associated with the mild and moderate phenotype (p < 0.001). The Face2Gene application showed a significant difference between XLMTM patients and unaffected controls (p = 0.001). CONCLUSIONS Using genotype-phenotype correlations could predict the disease course in most XLMTM patients, but still with limitations. The Face2Gene application seems to be a practical, non-invasive diagnostic approach in XLMTM using the correct algorithm.
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Affiliation(s)
- Katarína Kušíková
- Department of Pediatric Neurology, Faculty of Medicine, Comenius University Bratislava and National Institute of Children’s Diseases, 83340 Bratislava, Slovakia; (K.K.)
| | - Andrea Šoltýsová
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215 Bratislava, Slovakia
- Institute for Clinical and Translational Research, Biomedical Research Center, Slovak Academy of Sciences, 84505 Bratislava, Slovakia
| | - Andrej Ficek
- Department of Molecular Biology, Faculty of Natural Sciences, Comenius University, 84215 Bratislava, Slovakia
| | - René G. Feichtinger
- University Children’s Hospital, SalzburgerLandeskliniken (SALK), Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (R.G.F.)
| | - Johannes A. Mayr
- University Children’s Hospital, SalzburgerLandeskliniken (SALK), Paracelsus Medical University Salzburg, 5020 Salzburg, Austria; (R.G.F.)
| | - Martina Škopková
- Department of Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Science, 84505 Bratislava, Slovakia
| | - Daniela Gašperíková
- Department of Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Science, 84505 Bratislava, Slovakia
| | - Miriam Kolníková
- Department of Pediatric Neurology, Faculty of Medicine, Comenius University Bratislava and National Institute of Children’s Diseases, 83340 Bratislava, Slovakia; (K.K.)
| | - Karoline Ornig
- Division of Neuropathology, Department of Pathology and Molecular Pathology, Neuromed Campus, Kepler University Hospital, Johannes Kepler University, 4020 Linz, Austria
| | - Ognian Kalev
- Division of Neuropathology, Department of Pathology and Molecular Pathology, Neuromed Campus, Kepler University Hospital, Johannes Kepler University, 4020 Linz, Austria
| | - Serge Weis
- Division of Neuropathology, Department of Pathology and Molecular Pathology, Neuromed Campus, Kepler University Hospital, Johannes Kepler University, 4020 Linz, Austria
| | - Denisa Weis
- Department of Medical Genetics, Kepler University Hospital Med Campus IV, Johannes Kepler University, 4020 Linz, Austria
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Jin N, Xv D, Xv YT, Li XM, Jiang Y, Zhu JP, Lu JF, Luo Q. Whole exome sequencing discloses a pathogenic MTM1 gene mutation in a continuous polyhydramnios family in China: Case report and literature review. Eur J Obstet Gynecol Reprod Biol 2023; 291:34-38. [PMID: 37813004 DOI: 10.1016/j.ejogrb.2023.10.001] [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: 09/03/2023] [Accepted: 10/01/2023] [Indexed: 10/11/2023]
Abstract
Polyhydramnios can be caused by genetic defects at times. However, to establish an accurate diagnosis and provide a precise prenatal consultation in a given case is still a great challenge toward obstetricians. To uncover the genetic cause of polyhydramnios in the two consecutive pregnancies, we performed whole-exome sequencing of DNA for the second suffering fetuses, their parents, and targeted sanger sequencing of other members of this family. We discovered a hemizygous truncating variant in MTM1 gene, c.438_439 del (p. H146Q fs*10) in this Chinese family. In the light of the molecular discoveries, the fetus's clinical phenotype was considered to be a good fit for X-linked myotubular myopathy (XLMTM). There is no related research to the prenatal manifestations of MTM1-related XLMTM among Chinese population, and this is the first one to present. Though the etiology of polyhydramnios is complicated, WES may provide us with a creative avenue in prenatal diagnosis.
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Affiliation(s)
- Neng Jin
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 310000, China
| | - Dong Xv
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 310000, China
| | - Ye-Tao Xv
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Nanjing Medical Universtiy, Nanjing 210029, China
| | - Xing-Miao Li
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 310000, China
| | - Ying Jiang
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 310000, China
| | - Jing-Ping Zhu
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 310000, China
| | - Jve-Fei Lu
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 310000, China; Tong Xiang Maternaity and Child Health Care Hospital, Tongxiang 314500, China
| | - Qiong Luo
- Department of Obstetrics, Women's Hospital, School of Medicine, Zhejiang University, 310000, China.
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4
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Campbell L, Fredericks J, Mathivha K, Moshesh P, Coovadia A, Chirwa P, Dillon B, Ghoor A, Lawrence D, Nair L, Mabaso N, Mokwele D, Novellie M, Krause A, Carstens N. The implementation and utility of clinical exome sequencing in a South African infant cohort. Front Genet 2023; 14:1277948. [PMID: 38028619 PMCID: PMC10665497 DOI: 10.3389/fgene.2023.1277948] [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: 08/15/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Genetic disorders are significant contributors to infant hospitalization and mortality globally. The early diagnosis of these conditions in infants remains a considerable challenge. Clinical exome sequencing (CES) has shown to be a successful tool for the early diagnosis of genetic conditions, however, its utility in African infant populations has not been investigated. The impact of the under-representation of African genomic data, the cost of testing, and genomic workforce shortages, need to be investigated and evidence-based implementation strategies accounting for locally available genetics expertise and diagnostic infrastructure need to be developed. We evaluated the diagnostic utility of singleton CES in a cohort of 32 ill, South African infants from two State hospitals in Johannesburg, South Africa. We analysed the data using a series of filtering approaches, including a curated virtual gene panel consisting of genes implicated in neonatal-and early childhood-onset conditions and genes with known founder and common variants in African populations. We reported a diagnostic yield of 22% and identified seven pathogenic variants in the NPHS1, COL2A1, OCRL, SHOC2, TPRV4, MTM1 and STAC3 genes. This study demonstrates the utility value of CES in the South African State healthcare setting, providing a diagnosis to patients who would otherwise not receive one and allowing for directed management. We anticipate an increase in the diagnostic yield of our workflow with further refinement of the study inclusion criteria. This study highlights important considerations for the implementation of genomic medicine in under-resourced settings and in under-represented African populations where variant interpretation remains a challenge.
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Affiliation(s)
- L. Campbell
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - J. Fredericks
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - K. Mathivha
- Department of Paediatrics and Child Health, School of Clinical Medicine, Nelson Mandela Children’s Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - P. Moshesh
- Department of Paediatrics and Child Health, School of Clinical Medicine, Nelson Mandela Children’s Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - A. Coovadia
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - P. Chirwa
- Nelson Mandela Children’s Hospital, Johannesburg, South Africa
| | - B. Dillon
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - A. Ghoor
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - D. Lawrence
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - L. Nair
- Department of Paediatrics and Child Health, School of Clinical Medicine, Rahima Moosa Mother and Child Hospital, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - N. Mabaso
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - D. Mokwele
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - M. Novellie
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - A. Krause
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - N. Carstens
- Division of Human Genetics, National Health Laboratory Service andSchool of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Genomics Platform, South African Medical Research Council, Cape Town, South Africa
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Bhattacharyya T, Ghosh A, Verma S, Raghu P, Sowdhamini R. Structural rationale to understand the effect of disease-associated mutations on Myotubularin. Curr Res Struct Biol 2023; 5:100100. [PMID: 37101954 PMCID: PMC10123148 DOI: 10.1016/j.crstbi.2023.100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 02/16/2023] [Accepted: 02/28/2023] [Indexed: 03/29/2023] Open
Abstract
Myotubularin or MTM1 is a lipid phosphatase that regulates vesicular trafficking in the cell. The MTM1 gene is mutated in a severe form of muscular disease, X-linked myotubular myopathy or XLMTM, affecting 1 in 50,000 newborn males worldwide. There have been several studies on the disease pathology of XLMTM, but the structural effects of missense mutations of MTM1 are underexplored due to the unavailability of a crystal structure. MTM1 consists of three domains-a lipid-binding N-terminal GRAM domain, the phosphatase domain and a coiled-coil domain which aids dimerisation of Myotubularin homologs. While most mutations reported to date map to the phosphatase domain of MTM1, the other two domains on the sequence are also frequently mutated in XLMTM. To understand the overall structural and functional effects of missense mutations on MTM1, we curated several missense mutations and performed in silico and in vitro studies. Apart from significantly impaired binding to substrate, abrogation of phosphatase activity was observed for a few mutants. Possible long-range effects of mutations from non-catalytic domains on phosphatase activity were observed as well. Coiled-coil domain mutants have been characterised here for the first time in XLMTM literature.
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Jang W, Puchkov D, Samsó P, Liang Y, Nadler-Holly M, Sigrist SJ, Kintscher U, Liu F, Mamchaoui K, Mouly V, Haucke V. Endosomal lipid signaling reshapes the endoplasmic reticulum to control mitochondrial function. Science 2022; 378:eabq5209. [PMID: 36520888 DOI: 10.1126/science.abq5209] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cells respond to fluctuating nutrient supply by adaptive changes in organelle dynamics and in metabolism. How such changes are orchestrated on a cell-wide scale is unknown. We show that endosomal signaling lipid turnover by MTM1, a phosphatidylinositol 3-phosphate [PI(3)P] 3-phosphatase mutated in X-linked centronuclear myopathy in humans, controls mitochondrial morphology and function by reshaping the endoplasmic reticulum (ER). Starvation-induced endosomal recruitment of MTM1 impairs PI(3)P-dependent contact formation between tubular ER membranes and early endosomes, resulting in the conversion of ER tubules into sheets, the inhibition of mitochondrial fission, and sustained oxidative metabolism. Our results unravel an important role for early endosomal lipid signaling in controlling ER shape and, thereby, mitochondrial form and function to enable cells to adapt to fluctuating nutrient environments.
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Affiliation(s)
- Wonyul Jang
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Dmytro Puchkov
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Paula Samsó
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - YongTian Liang
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Michal Nadler-Holly
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Stephan J Sigrist
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Fan Liu
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.,Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Kamel Mamchaoui
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France
| | - Vincent Mouly
- Centre de Recherche en Myologie, Institut de Myologie, Inserm, Sorbonne Université, 75013 Paris, France
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.,Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany.,Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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7
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Lyu S, Arends D, Nassar MK, Weigend A, Weigend S, Wang E, Brockmann GA. High-density genotyping reveals candidate genomic regions for chicken body size in breeds of Asian origin. Poult Sci 2022; 102:102303. [PMID: 36436378 PMCID: PMC9706647 DOI: 10.1016/j.psj.2022.102303] [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: 10/19/2021] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 11/06/2022] Open
Abstract
Body size is one of the main selection indices in chicken breeding. Although often investigated, knowledge of the underlying genetic mechanisms is incomplete. The aim of the current study was to identify genomic regions associated with body size differences between Asian Game and Asian Bantam type chickens. In this study, 94 and 107 chickens from 4 Asian Game and 5 Asian Bantam type breeds, respectively, were genotyped using the chicken 580K single nucleotide polymorphism (SNP) array. A genome-wide association study (GWAS) and principal component analyses (PCA) were performed to identify genomic regions associated with body size related-traits such as wing length, shank length, shank thickness, keel length, and body weight. Hierarchical clustering of genotype data showed a clear genetic difference between the investigated Asian Game and Asian Bantam chicken types. GWAS identified 16 genomic regions associated with wing length (2, FDR ≤ 0.018), shank thickness (6, FDR ≤ 0.008), keel length (5, FDR ≤ 0.023), and body weight (3, FDR ≤ 0.041). PCA showed that the first principal component (PC1) separated the 2 chicken types and significantly correlated with the measured body size related-traits (P ≤ 2.24e-40). SNPs contributing significantly to PC1 were subjected to a more detailed investigation. This analysis identified 11 regions potentially associated with differences in body size related-traits. A region on chromosome 4 (GGA4) (17.3-21.3 Mb) was detected in both analyses GWAS and PCA. This region harbors 60 genes. Among them are myotubularin 1 (MTM1) and secreted frizzled-related protein 2 (SFPR2) which can be considered as potential candidate genes for body size related-traits. Our results clearly show that the investigated Asian Game type chicken breeds are genetically different from the Asian Bantam breeds. A region on GGA4 between 17.3 and 21.3 Mb was identified which contributes to the phenotypic difference, though further validation of candidate genes is necessary.
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Affiliation(s)
- Shijie Lyu
- Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universitt zu Berlin, Berlin 10115, Germany,Institute of Animal Science and Veterinary Medicine, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Danny Arends
- Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universitt zu Berlin, Berlin 10115, Germany,Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Mostafa K. Nassar
- Animal Production Department, Faculty of Agriculture, Cairo University, Giza 12613, Egypt
| | - Annett Weigend
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Neustadt-Mariensee 31535, Germany
| | - Steffen Weigend
- Institute of Farm Animal Genetics, Friedrich-Loeffler-Institut, Neustadt-Mariensee 31535, Germany
| | - Eryao Wang
- Institute of Animal Science and Veterinary Medicine, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Gudrun A. Brockmann
- Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universitt zu Berlin, Berlin 10115, Germany,Corresponding author:
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8
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Woo H, Lee S, Han JY, Kim WJ, Kim MJ, Seong MW, Kim SY, Cho A, Lim BC, Kim KJ, Chae JH. Clinical Characteristics and Neurologic Outcomes of X-Linked Myotubular Myopathy. ANNALS OF CHILD NEUROLOGY 2022. [DOI: 10.26815/acn.2022.00171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Purpose: X-linked myotubular myopathy (XLMTM) is a rare condition of centronuclear myopathy caused by myotubularin 1 (MTM1) mutations. Patients with XLMTM show different neurodevelopmental outcomes after the neonatal period depending on age and acquired hypoxic damage. We aim to evaluate the clinical characteristics and neurodevelopmental outcomes of patients with XLMTM who were followed up at a single center. It is essential to understand the volume and conditions to prepare for being a candidate for new therapeutic strategies. Methods: Patients diagnosed with centronuclear myopathy by muscle pathology and MTM1 mutation analysis were included. We retrospectively investigated motor milestones, communication skills, and bulbar and respiratory function in the patients. The patients were categorized into two groups: with and without hypoxic insults (HI). Results: All 13 patients were severely affected by neonatal hypotonia and required respiratory support and a feeding tube during the neonatal period. The follow-up duration was 4.4 years (range, 0.3 to 8.9). In the non-HI group, developmental milestones were delayed but were slowly achieved. Some patients underwent training in oral feeding with thickened foods and weaning from ventilation. Patients with HI showed poor motor function catch-up and communication skills. Three deaths were associated with acute respiratory failure.Conclusion: Patients with XLMTM without HI can survive long-term with the slow achievement of motor milestones and bulbar and respiratory function. However, hypoxic brain damage following acute respiratory failure negatively influences their developmental potential or even lead to death. Therefore, parental education for proper respiratory management is necessary, especially for young children.
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9
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Ceyhan Y, Zhang M, Sandoval CG, Agoulnik AI, Agoulnik IU. Expression pattern and the roles of phosphatidylinositol phosphatases in testis. Biol Reprod 2022; 107:902-915. [PMID: 35766372 DOI: 10.1093/biolre/ioac132] [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: 03/23/2022] [Revised: 06/02/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphoinositides (PIs) are relatively rare lipid components of the cellular membranes. Their homeostasis is tightly controlled by specific PI kinases and phosphatases. PIs play essential roles in cellular signaling, cytoskeletal organization, and secretory processes in various diseases and normal physiology. Gene targeting experiments strongly suggest that in mice with deficiency of several PI phosphatases such as Pten, Mtmrs, Inpp4b, and Inpp5b, spermatogenesis is affected, resulting in partial or complete infertility. Similarly, in men, loss of several of the PIP phosphatases is observed in infertility characterized by the lack of mature sperm. Using available gene expression databases, we compare expression of known PI phosphatases in various testicular cell types, infertility patients, and mouse age-dependent testicular gene expression, and discuss their potential roles in testis physiology and spermatogenesis.
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Affiliation(s)
- Yasemin Ceyhan
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Manqi Zhang
- Department of Medicine, Duke University, Durham, NC, USA
| | - Carlos G Sandoval
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,New York University Grossman School of Medicine, New York, NY, USA
| | - Alexander I Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Irina U Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
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10
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Lawlor MW, Dowling JJ. X-linked myotubular myopathy. Neuromuscul Disord 2021; 31:1004-1012. [PMID: 34736623 DOI: 10.1016/j.nmd.2021.08.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 07/23/2021] [Accepted: 08/05/2021] [Indexed: 12/28/2022]
Abstract
X-linked myotubular myopathy (XLMTM) is a severe congenital muscle disease caused by mutation in the MTM1 gene. MTM1 encodes myotubularin (MTM1), an endosomal phosphatase that acts to dephosphorylate key second messenger lipids PI3P and PI3,5P2. XLMTM is clinically characterized by profound muscle weakness and associated with multiple disabilities (including ventilator and wheelchair dependence) and early death in most affected individuals. The disease is classically defined by characteristic changes observed on muscle biopsy, including centrally located nuclei, myofiber hypotrophy, and organelle disorganization. In this review, we highlight the clinical and pathologic features of the disease, present concepts related to disease pathomechanisms, and present recent advances in therapy development.
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Affiliation(s)
- Michael W Lawlor
- Department of Pathology and Laboratory Medicine and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - James J Dowling
- Division of Neurology and Program for Genetics and Genome Biology, Hospital for Sick Children, 555 University Ave., Toronto, ON M5G 1X8, Canada; Departments of Paediatrics and Molecular Genetics, University of Toronto, Canada.
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11
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Miyado M, Fukami M, Ogata T. MAMLD1 and Differences/Disorders of Sex Development: An Update. Sex Dev 2021; 16:126-137. [PMID: 34695834 DOI: 10.1159/000519298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 08/27/2021] [Indexed: 11/19/2022] Open
Abstract
MAMLD1 (alias CXorf6) was first documented in 2006 as a causative gene of 46,XY differences/disorders of sex development (DSD). MAMLD1/Mamld1 is expressed in the fetal testis and is predicted to enhance the expression of several Leydig cell-specific genes. To date, hemizygous MAMLD1 variants have been identified in multiple 46,XY individuals with hypomasculinized external genitalia. Pathogenic MAMLD1 variants are likely to cause genital abnormalities at birth and are possibly associated with age-dependent deterioration of testicular function. In addition, some MAMLD1 variants have been identified in 46,XX individuals with ovarian dysfunction. However, recent studies have raised the possibility that MAMLD1 variants cause 46,XY DSD and ovarian dysfunction as oligogenic disorders. Unsolved issues regarding MAMLD1 include the association between MAMLD1 variants and 46,XX testicular DSD, gene-gene interactions in the development of MAMLD1-mediated DSD, and intracellular functions of MAMLD1.
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Affiliation(s)
- Mami Miyado
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Maki Fukami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Tsutomu Ogata
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan.,Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Striated Preferentially Expressed Protein Kinase (SPEG) in Muscle Development, Function, and Disease. Int J Mol Sci 2021; 22:ijms22115732. [PMID: 34072258 PMCID: PMC8199188 DOI: 10.3390/ijms22115732] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/23/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
Mutations in striated preferentially expressed protein kinase (SPEG), a member of the myosin light chain kinase protein family, are associated with centronuclear myopathy (CNM), cardiomyopathy, or a combination of both. Burgeoning evidence suggests that SPEG plays critical roles in the development, maintenance, and function of skeletal and cardiac muscles. Here we review the genotype-phenotype relationships and the molecular mechanisms of SPEG-related diseases. This review will focus on the progress made toward characterizing SPEG and its interacting partners, and its multifaceted functions in muscle regeneration, triad development and maintenance, and excitation-contraction coupling. We will also discuss future directions that are yet to be investigated including understanding of its tissue-specific roles, finding additional interacting proteins and their relationships. Understanding the basic mechanisms by which SPEG regulates muscle development and function will provide critical insights into these essential processes and help identify therapeutic targets in SPEG-related disorders.
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Reumers SFI, Braun F, Spillane JE, Böhm J, Pennings M, Schouten M, van der Kooi AJ, Foley AR, Bönnemann CG, Kamsteeg EJ, Erasmus CE, Schara-Schmidt U, Jungbluth H, Voermans NC. Spectrum of Clinical Features in X-Linked Myotubular Myopathy Carriers: An International Questionnaire Study. Neurology 2021; 97:e501-e512. [PMID: 34011573 DOI: 10.1212/wnl.0000000000012236] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/26/2021] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To characterize the spectrum of clinical features in a cohort of X-linked myotubular myopathy (XL-MTM) carriers, including prevalence, genetic features, clinical symptoms, and signs, as well as associated disease burden. METHODS We performed a cross-sectional online questionnaire study among XL-MTM carriers. Participants were recruited from patient associations, medical centers, and registries in the United Kingdom, Germany, and the Netherlands. We used a custom-made questionnaire, the Checklist Individual Strength (CIS), the Frenchay Activities Index (FAI), the Short Form 12 (SF-12) health survey, and the McGill Pain Questionnaire. Carriers were classified as manifesting or nonmanifesting on the basis of self-reported ambulation and muscle weakness. RESULTS The prevalence of manifesting carriers in this study population (n = 76) was 51%, subdivided into mild (independent ambulation, 39%), moderate (assisted ambulation, 9%), and severe (wheelchair dependent, 3%) phenotypes. In addition to muscle weakness, manifesting carriers frequently reported fatigue (70%) and exercise intolerance (49%). Manifesting carriers scored higher on the overall CIS (p = 0.001), the fatigue subscale (p < 0.001), and least severe pain subscale (p = 0.005) than nonmanifesting carriers. They scored lower on the FAI (p = 0.005) and the physical component of the SF-12 health survey (p < 0.001). CONCLUSIONS The prevalence of manifesting XL-MTM carriers may be higher than currently assumed, most having a mild phenotype and a wide variety of symptoms. Manifesting carriers are particularly affected by fatigue, limitations of daily activities, pain, and reduced quality of life. Our findings should increase awareness and provide useful information for health care providers and future clinical trials.
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Affiliation(s)
- Stacha F I Reumers
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Frederik Braun
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Jennifer E Spillane
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Johann Böhm
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Maartje Pennings
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Meyke Schouten
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Anneke J van der Kooi
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - A Reghan Foley
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Carsten G Bönnemann
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Erik-Jan Kamsteeg
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Corrie E Erasmus
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Ulrike Schara-Schmidt
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Heinz Jungbluth
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK
| | - Nicol C Voermans
- From the Department of Neurology (S.F.I.R., N.C.V.), Donders Institute for Brain, Cognition and Behaviour, Department of Human Genetics (M.P., E.-j.K.), and Department of Clinical Genetics (M.S.), Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pediatric Neurology and Neuromuscular Centre (F.B., U.S.-S.), University Hospital Essen, Germany; Department of Neurology (J.E.S.), St. Thomas Hospital, and Department of Paediatric Neurology (H.J.), Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK; Department of Neurobiology and Genetics (J.B.), Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Department of Neurology (A.J.v.d.K.), Amsterdam University Medical Center, Neuroscience Institute, the Netherlands; Neuromuscular and Neurogenetic Disorders of Childhood Section (A.R.F., C.G.B.), National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD; Department of Pediatric Neurology (C.E.E.), Radboud University Medical Center Amalia Children's Hospital, Nijmegen, the Netherlands; and Muscle Signalling Section (H.J.), Randall Division for Cell and Molecular Biophysics, King's College, London, UK.
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Sacks NC, Healey BE, Cyr PL, Slocomb T, James E, Beggs AH, Graham RJ. Costs and health resource use in patients with X-linked myotubular myopathy: insights from US commercial claims. J Manag Care Spec Pharm 2021; 27:1019-1026. [PMID: 33843254 PMCID: PMC10394177 DOI: 10.18553/jmcp.2021.20501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND: In X-linked myotubular myopathy (XLMTM), mutations in the MTM1 gene result in absence or dysfunction of myotubularin, a protein required for normal development, maintenance, and function of skeletal muscle. Extreme muscle weakness results in severe respiratory failure that is fatal for approximately half of XLMTM-affected children by age 18 months. Most surviving patients require invasive mechanical ventilation, feeding tubes, and wheelchairs for mobility, due to profoundly impaired motor function. Little is known about the costs of care for this rare disease. Currently, there are no approved therapies for XLMTM. OBJECTIVE: To quantify the direct medical costs and health care resource utilization (HRU) incurred by XLMTM patients and paid by commercial insurers. METHODS: A retrospective, longitudinal study was conducted using the IQVIA PharMetrics Plus commercial database of adjudicated claims for more than 140 million individuals with commercial insurance coverage in the United States. An algorithm based on demographic information, diagnosis and procedure codes, and medications was used to identify XLMTM patients younger than aged 2 years during the study period from January 1, 2006, through September 30, 2018. All-cause direct medical costs and HRU during each month were calculated. Costs were grouped as inpatient hospital admissions (including the intensive care unit or neonatal intensive care unit [NICU]); emergency department visits; outpatient services (outpatient hospital visits, office visits, physician/provider office visits, ambulatory surgeries and procedures, laboratory tests, and imaging tests); and prescription medications. Monthly costs and HRU over time were stratified by age and use of mechanical ventilation. RESULTS: 49 patients met the study criteria. All had at least 1 inpatient hospital admission, and 36 (73%) had at least 1 NICU stay. All patients received ventilation at some time during the study period, including 40 (82%) treated with invasive ventilation. Mean monthly per patient direct medical costs were highest in the first year of life ($74,831), including costs for inpatient admissions ($69,025), outpatient services ($5,266), and prescription medication ($540). Mean monthly costs were lower in the second, third, and fourth years of life ($23,207, $13,044, and $9,440, respectively). When annualized, these all-cause monthly medical costs totaled $897,978 per patient in the first year of life and nearly $1.5 million total for patients who survived the first 4 years of life. Costs were consistently highest when patients were receiving invasive ventilation and lowest when they were not receiving ventilation (i.e., before they started on ventilator support). CONCLUSIONS: This direct health care cost and HRU analysis demonstrates the substantial economic burden associated with XLMTM. Costs are highest in the first year of life and are particularly significant for patients receiving invasive ventilation. DISCLOSURES: This study was funded by Audentes Therapeutics, an Astellas Company, and was conducted by PRECISIONheor with funding from Audentes Therapeutics, an Astellas Company. Slocomb is an employee of Audentes Therapeutics, an Astellas Company; James was an employee at the time of the study. Sacks, Healey, and Cyr are employees of PRECISIONheor. Graham participated in the medical/scientific advisory board for Audentes as part of a clinical trial design for XLMTM but declares no vested interest or holdings that would represent a conflict of interest. Beggs received consulting fees from Audentes Therapeutics, for work on this study, and has received grants from Alexion Pharmaceuticals, Audentes Therapeutics, Dynacure SAS, Pfizer Pharmaceuticals, along with personal fees from Asklepios Biopharmaceutical, Inc., Ballard Biologics, Biogen, F. Hoffmann-La Roche AG, GLG, Guidepoint Global, and Kate Therapeutics, unrelated to this study. In addition, Beggs has a patent (Patent number: 10736945) for systemic gene replacement therapy for treatment of X-linked myotubular myopathy (XLMTM) licensed to Audentes Therapeutics.
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Affiliation(s)
- Naomi C Sacks
- Precision Health Economics and Outcomes Research and Tufts University School of Medicine, Boston, MA
| | | | - Philip L Cyr
- Precision Health Economics and Outcomes Research, Boston, MA, and College of Health and Human Services, University of North Carolina, Charlotte
| | | | - Emma James
- Audentes Therapeutics, San Francisco, CA
| | - Alan H Beggs
- Harvard Medical School and Boston Children's Hospital, Boston, MA
| | - Robert J Graham
- Harvard Medical School and Boston Children's Hospital, Boston, MA
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15
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Souza LS, Almeida CF, Yamamoto GL, Pavanello RDCM, Gurgel-Giannetti J, da Costa SS, Anequini IP, do Carmo SA, Wang JYT, Scliar MDO, Castelli EC, Otto PA, Zanoteli E, Vainzof M. Manifesting carriers of X-linked myotubular myopathy: Genetic modifiers modulating the phenotype. NEUROLOGY-GENETICS 2020; 6:e513. [PMID: 33062893 PMCID: PMC7524580 DOI: 10.1212/nxg.0000000000000513] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 07/16/2020] [Indexed: 12/18/2022]
Abstract
Objective To analyze the modulation of the phenotype in manifesting carriers of recessive X-linked myotubular myopathy (XLMTM), searching for possible genetic modifiers. Methods Twelve Brazilian families with XLMTM were molecularly and clinically evaluated. In 2 families, 4 of 6 and 2 of 5 manifesting female carriers were identified. These females were studied for X chromosome inactivation. In addition, whole-exome sequencing was performed, looking for possible modifier variants. We also determined the penetrance rate among carriers of the mutations responsible for the condition. Results Mutations in the MTM1 gene were identified in all index patients from the 12 families, being 4 of them novel. In the heterozygotes, X chromosome inactivation was random in 3 of 4 informative manifesting carriers. The disease penetrance rate was estimated to be 30%, compatible with incomplete penetrance. Exome comparative analyses identified variants within a segment of 4.2 Mb on chromosome 19, containing the killer cell immunoglobulin-like receptor cluster of genes that were present in all nonmanifesting carriers and absent in all manifesting carriers. We hypothesized that these killer cell immunoglobulin-like receptor variants may modulate the phenotype, acting as a protective factor in the nonmanifesting carriers. Conclusions Affected XLMTM female carriers have been described with a surprisingly high frequency for a recessive X-linked disease, raising the question about the pattern of inheritance or the role of modifier factors acting on the disease phenotype. We demonstrated the possible existence of genetic mechanisms and variants accountable for the clinical manifestation in these women, which can become future targets for therapies.
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Affiliation(s)
- Lucas Santos Souza
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Camila Freitas Almeida
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Guilherme Lopes Yamamoto
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Rita de Cássia Mingroni Pavanello
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Juliana Gurgel-Giannetti
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Silvia Souza da Costa
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Isabela Pessa Anequini
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Silvana Amanda do Carmo
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Jaqueline Yu Ting Wang
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Marília de Oliveira Scliar
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Erick C Castelli
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Paulo Alberto Otto
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Edmar Zanoteli
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
| | - Mariz Vainzof
- Human Genome and Stem Cell Research Center (L.S.S., C.F.A., G.L.Y., R.d.C.M.P., S.S.d.C., I.P.A., S.A.d.C., J.Y.T.W., M.d.O.S., P.A.O., M.V.), University of São Paulo; Department of Pediatrics (J.G.-G.), Medical School of Federal University of Minas Gerais, Belo Horizonte; Pathology Department (E.C.C.), School of Medicine, São Paulo State University (UNESP), Botucatu; and Department of Neurology (E.Z.), Medical School (FMUSP), University of São Paulo, Brazil
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16
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Li L, Su C, Fan L, Gao F, Liang X, Gong C. Clinical and molecular spectrum of 46,XY disorders of sex development that harbour MAMLD1 variations: case series and review of literature. Orphanet J Rare Dis 2020; 15:188. [PMID: 32690052 PMCID: PMC7370409 DOI: 10.1186/s13023-020-01459-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/30/2020] [Indexed: 12/20/2022] Open
Abstract
Background Mastermind-like domain-containing 1 (MAMLD1) has previously been identified as a causative gene for “46,XY Disorders of Sex Development (DSD)”. Recently, there has been some controversy regarding the causative role of MAMLD1 variations in DSDs. Here we describe a clinical series and review the reported cases to evaluate the role of MAMLD1 variants in children with 46,XY DSD. Cases of 46,XY DSD harbouring MAMLD1 variants from unrelated families were recruited from the Beijing Children’s Hospital in China (N = 10) or identified through a literature search (N = 26). The clinical manifestations and genetic variants of all the patients were evaluated. Results Hypospadias was the most prevalent phenotype among our 10 cases (8 out of 10 cases) and in all the previously reported ones. Central precocious puberty and isolated micropenis were observed for the first time. Among the 10 cases, nine variants were identified, including three nonsense (p.R356X, p.Q152X, and p.Q124X) and six missense (p.P334S, p.S662R, p.A421P,p.T992I, p.P542S, and p.R927L) variants. In silico analysis showed that the variants p.P334S, p.P542S, p.S662R, and p.R927Lmight lead to drastic changes in the interaction force of the amino acid chain and the flexibility of the spatial structure, and such changes may affect protein function. Conclusion Patients with 46,XY DSD harbouring MAMLD1variants manifest a broad spectrum of phenotypes and mostly present with hypospadias. The six novel variants reported here enrich the mutation database and contribute to our understanding of the pathogenesis of 46,XY DSD.
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Affiliation(s)
- Lele Li
- Department of Endocrinology, Genetics, Metabolism and Adolescent Medicine, Beijing Children's Hospital, the Capital Medical University, National Center for Children's Health, 56# Nan Lishi Rd, West District, Beijing, 100045, P. R. China
| | - Chang Su
- Department of Endocrinology, Genetics, Metabolism and Adolescent Medicine, Beijing Children's Hospital, the Capital Medical University, National Center for Children's Health, 56# Nan Lishi Rd, West District, Beijing, 100045, P. R. China
| | - Lijun Fan
- Department of Endocrinology, Genetics, Metabolism and Adolescent Medicine, Beijing Children's Hospital, the Capital Medical University, National Center for Children's Health, 56# Nan Lishi Rd, West District, Beijing, 100045, P. R. China
| | - Fenqi Gao
- Department of Endocrinology, Genetics, Metabolism and Adolescent Medicine, Beijing Children's Hospital, the Capital Medical University, National Center for Children's Health, 56# Nan Lishi Rd, West District, Beijing, 100045, P. R. China
| | - Xuejun Liang
- Department of Endocrinology, Genetics, Metabolism and Adolescent Medicine, Beijing Children's Hospital, the Capital Medical University, National Center for Children's Health, 56# Nan Lishi Rd, West District, Beijing, 100045, P. R. China
| | - Chunxiu Gong
- Department of Endocrinology, Genetics, Metabolism and Adolescent Medicine, Beijing Children's Hospital, the Capital Medical University, National Center for Children's Health, 56# Nan Lishi Rd, West District, Beijing, 100045, P. R. China.
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17
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Li L, Gao F, Fan L, Su C, Liang X, Gong C. Disorders of Sex Development in Individuals Harbouring MAMLD1 Variants: WES and Interactome Evidence of Oligogenic Inheritance. Front Endocrinol (Lausanne) 2020; 11:582516. [PMID: 33424767 PMCID: PMC7786837 DOI: 10.3389/fendo.2020.582516] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 11/17/2020] [Indexed: 12/11/2022] Open
Abstract
Mastermind-like domain-containing 1 (MAMLD1) has been shown to play an important role in the process of sexual development and is associated with 46,XY disorders of sex development (DSDs). However, the causative role of MAMLD1 variations in DSDs remains disputable. In this study, we have described a clinical series on children from unrelated families with 46,XY DSD harbouring MAMLD1 variants. Whole exome sequencing (WES) was performed for each patient. WES data were filtered using common tools and disease customisation algorithms, including comparison against lists of known and candidate MAMLD1-related and DSD-related genes. Lastly, we investigated the hypothesis that MAMLD1-related DSD may follow an oligogenic mode of inheritance. Forty-three potentially deleterious/candidate variants of 18 genes (RET, CDH23, MYO7A, NOTCH2, MAML1, MAML2, CYP1A1, WNT9B, GLI2, GLI3, MAML3, WNT9A, FRAS1, PIK3R3, FREM2, PTPN11, EVC, and FLNA) were identified, which may have contributed to the patient phenotypes. MYO7A was the most commonly identified gene. Specific gene combinations were also identified. In the interactome analysis, MAMLD1 exhibited direct connection with MAML1/2/3 and NOTCH1/2. Through NOTCH1/2, the following eight genes were shown to be associated with MAMLD1:WNT9A/9B, GLI2/3, RET, FLNA, PTPN11, and EYA1. Our findings provide further evidence that individuals with MAMLD1-related 46,XY DSD could carry two or more variants of known DSD-related genes, and the phenotypic outcome of affected individuals might be determined by multiple genes.
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18
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Volpatti JR, Al-Maawali A, Smith L, Al-Hashim A, Brill JA, Dowling JJ. The expanding spectrum of neurological disorders of phosphoinositide metabolism. Dis Model Mech 2019; 12:12/8/dmm038174. [PMID: 31413155 PMCID: PMC6737944 DOI: 10.1242/dmm.038174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositides (PIPs) are a ubiquitous group of seven low-abundance phospholipids that play a crucial role in defining localized membrane properties and that regulate myriad cellular processes, including cytoskeletal remodeling, cell signaling cascades, ion channel activity and membrane traffic. PIP homeostasis is tightly regulated by numerous inositol kinases and phosphatases, which phosphorylate and dephosphorylate distinct PIP species. The importance of these phospholipids, and of the enzymes that regulate them, is increasingly being recognized, with the identification of human neurological disorders that are caused by mutations in PIP-modulating enzymes. Genetic disorders of PIP metabolism include forms of epilepsy, neurodegenerative disease, brain malformation syndromes, peripheral neuropathy and congenital myopathy. In this Review, we provide an overview of PIP function and regulation, delineate the disorders associated with mutations in genes that modulate or utilize PIPs, and discuss what is understood about gene function and disease pathogenesis as established through animal models of these diseases. Summary: This Review highlights the intersection between phosphoinositides and the enzymes that regulate their metabolism, which together are crucial regulators of myriad cellular processes and neurological disorders.
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Affiliation(s)
- Jonathan R Volpatti
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Almundher Al-Maawali
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Lindsay Smith
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Aqeela Al-Hashim
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Neuroscience, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Julie A Brill
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - James J Dowling
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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Abstract
Ryanodine receptor type 1-related myopathies (RYR1-RM) are the most common class of congenital myopathies. Historically, RYR1-RM classification and diagnosis have been guided by histopathologic findings on muscle biopsy. Main histological subtypes of RYR1-RM include central core disease, multiminicore disease, core-rod myopathy, centronuclear myopathy, and congenital fiber-type disproportion. A range of RYR1-RM clinical phenotypes has also emerged more recently and includes King Denborough syndrome, RYR1 rhabdomyolysis-myalgia syndrome, atypical periodic paralysis, congenital neuromuscular disease with uniform type 1 fibers, and late-onset axial myopathy. This expansion of the RYR1-RM disease spectrum is due, in part, to implementation of next-generation sequencing methods, which include the entire RYR1 coding sequence rather than being restricted to hotspot regions. These methods enhance diagnostic capabilities, especially given historic limitations of histopathologic and clinical overlap across RYR1-RM. Both dominant and recessive modes of inheritance have been documented, with the latter typically associated with a more severe clinical phenotype. As with all congenital myopathies, no FDA-approved treatments exist to date. Here, we review histopathologic, clinical, imaging, and genetic diagnostic features of the main RYR1-RM subtypes. We also discuss the current state of treatments and focus on disease-modulating (nongenetic) therapeutic strategies under development for RYR1-RM. Finally, perspectives for future approaches to treatment development are broached.
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Affiliation(s)
- Tokunbor A Lawal
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Joshua J Todd
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Katherine G Meilleur
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA.
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20
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Affected female carriers of MTM1 mutations display a wide spectrum of clinical and pathological involvement: delineating diagnostic clues. Acta Neuropathol 2017; 134:889-904. [PMID: 28685322 DOI: 10.1007/s00401-017-1748-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/24/2017] [Accepted: 07/02/2017] [Indexed: 01/14/2023]
Abstract
X-linked myotubular myopathy (XLMTM), a severe congenital myopathy, is caused by mutations in the MTM1 gene located on the X chromosome. A majority of affected males die in the early postnatal period, whereas female carriers are believed to be usually asymptomatic. Nevertheless, several affected females have been reported. To assess the phenotypic and pathological spectra of carrier females and to delineate diagnostic clues, we characterized 17 new unrelated affected females and performed a detailed comparison with previously reported cases at the clinical, muscle imaging, histological, ultrastructural and molecular levels. Taken together, the analysis of this large cohort of 43 cases highlights a wide spectrum of clinical severity ranging from severe neonatal and generalized weakness, similar to XLMTM male, to milder adult forms. Several females show a decline in respiratory function. Asymmetric weakness is a noteworthy frequent specific feature potentially correlated to an increased prevalence of highly skewed X inactivation. Asymmetry of growth was also noted. Other diagnostic clues include facial weakness, ptosis and ophthalmoplegia, skeletal and joint abnormalities, and histopathological signs that are hallmarks of centronuclear myopathy such as centralized nuclei and necklace fibers. The histopathological findings also demonstrate a general disorganization of muscle structure in addition to these specific hallmarks. Thus, MTM1 mutations in carrier females define a specific myopathy, which may be independent of the presence of an XLMTM male in the family. As several of the reported affected females carry large heterozygous MTM1 deletions not detectable by Sanger sequencing, and as milder phenotypes present as adult-onset limb-girdle myopathy, the prevalence of this myopathy is likely to be greatly underestimated. This report should aid diagnosis and thus the clinical management and genetic counseling of MTM1 carrier females. Furthermore, the clinical and pathological history of this cohort may be useful for therapeutic projects in males with XLMTM, as it illustrates the spectrum of possible evolution of the disease in patients surviving long term.
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21
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Eid W, Biason-Lauber A. Why boys will be boys and girls will be girls: Human sex development and its defects. ACTA ACUST UNITED AC 2017; 108:365-379. [PMID: 28033664 DOI: 10.1002/bdrc.21143] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Among the most defining events of an individual's life, is the development of a human embryo into male or a female. The phenotypic sex of an individual depends on the type of gonad that develops in the embryo, a process which itself is determined by the genetic setting of the individual. The development of the gonads is different from any other organ, as they possess the potential to differentiate into two functionally distinct organs, testes, or ovaries. Sex development can be divided into two distinctive processes, "sex determination," which is the commitment of the undifferentiated gonad into either a testis or an ovary, a process that is genetically programmed in a critically timed manner and "sex differentiation," which takes place through hormones produced by the gonads, once the developmental sex determination decision has been made. Disruption of any of the genes involved in either the testicular or ovarian development pathway could lead to disorders of sex development. In this review, we provide an insight into the factors important for sex determination, their antagonistic actions and whenever possible, references on the "prismatic" clinical cases are given. Birth Defects Research (Part C) 108:365-379, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Wassim Eid
- Division of Endocrinology, Department of Medicine, University of Fribourg, Fribourg, Switzerland.,Department of Biochemistry, Medical Research Institute, University of Alexandria, Alexandria, Egypt
| | - Anna Biason-Lauber
- Division of Endocrinology, Department of Medicine, University of Fribourg, Fribourg, Switzerland
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22
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Disrupted autophagy undermines skeletal muscle adaptation and integrity. Mamm Genome 2016; 27:525-537. [PMID: 27484057 PMCID: PMC5110612 DOI: 10.1007/s00335-016-9659-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/12/2016] [Indexed: 12/18/2022]
Abstract
This review assesses the importance of proteostasis in skeletal muscle maintenance with a specific emphasis on autophagy. Skeletal muscle appears to be particularly vulnerable to genetic defects in basal and induced autophagy, indicating that autophagy is co-substantial to skeletal muscle maintenance and adaptation. We discuss emerging evidence that tension-induced protein unfolding may act as a direct link between mechanical stress and autophagic pathways. Mechanistic links between protein damage, autophagy and muscle hypertrophy, which is also induced by mechanical stress, are still poorly understood. However, some mouse models of muscle disease show ameliorated symptoms upon effective targeting of basal autophagy. These findings highlight the importance of autophagy as therapeutic target and suggest that elucidating connections between protein unfolding and mTOR-dependent or mTOR-independent hypertrophic responses is likely to reveal specific therapeutic windows for the treatment of muscle wasting disorders.
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23
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Abath Neto O, Silva MRE, Martins CDA, Oliveira ADSB, Reed UC, Biancalana V, Pesquero JB, Laporte J, Zanoteli E. A Study of a Cohort of X-Linked Myotubular Myopathy at the Clinical, Histologic, and Genetic Levels. Pediatr Neurol 2016; 58:107-12. [PMID: 26995067 DOI: 10.1016/j.pediatrneurol.2016.01.023] [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: 09/09/2015] [Accepted: 01/30/2016] [Indexed: 01/01/2023]
Abstract
BACKGROUND Myotubular myopathy is a rare X-linked congenital myopathy characterized by marked neonatal hypotonia and respiratory insufficiency, facial and ocular involvement, and muscle biopsy with prominent central nuclei in the majority of muscle fibers. It is caused by mutations in MTM1, which codes for the phosphoinositides phosphatase myotubularin. In this work, we established and detailed a new cohort of six patients at the clinical, histologic, and genetic levels. PATIENTS AND METHODS Patients were recruited after screening 3065 muscle biopsy reports from two large biopsy banks in Sao Paulo, Brazil from the years 2008 to 2013, and from referrals to a neuromuscular outpatient clinic between 2011 and 2013. We reviewed biopsy slides, evaluated patients, and Sanger sequenced MTM1 in the families. RESULTS All patients but one had classic phenotypes with a stable course after a severe onset. Two patients died suddenly from hypovolemic shock. Muscle biopsies had been performed in five patients, all of whom showed a classic pattern with a predominance of centrally located nuclei and increased oxidative activity in the center of the fibers. Two patients showed necklace fibers, and two families had novel truncating mutations in MTM1. CONCLUSIONS X-linked myotubular myopathy is rare in the Brazilian population. Necklace fibers might be more prevalent in this condition than previously reported. Direct Sanger sequencing of MTM1 on clinical suspicion avoids the need of a muscle biopsy.
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Affiliation(s)
- Osorio Abath Neto
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | | | | | - Acary de Souza Bulle Oliveira
- Setor de Doenças Neuromusculares, Departamento de Neurologia, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Umbertina Conti Reed
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Valérie Biancalana
- Faculté de Médecine, Laboratoire de Diagnostic Génétique, Nouvel Hopital Civil, Strasbourg, France; Department of Translational Medicine and Neurogenetics, IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, Collège de France, Illkirch, France
| | - João Bosco Pesquero
- Departamento de Biofísica, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, IGBMC, INSERM U964, CNRS UMR7104, University of Strasbourg, Collège de France, Illkirch, France
| | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil.
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24
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Longo G, Russo S, Novelli G, Sangiuolo F, D'Apice M. Mutation spectrum of the MTM1
gene in XLMTM patients: 10 years of experience in prenatal and postnatal diagnosis. Clin Genet 2015; 89:93-8. [DOI: 10.1111/cge.12674] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 09/01/2015] [Accepted: 09/01/2015] [Indexed: 11/28/2022]
Affiliation(s)
- G. Longo
- Department of Biomedicine and Prevention; University of Rome ‘Tor Vergata’; Rome Italy
| | - S. Russo
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
| | - G. Novelli
- Department of Biomedicine and Prevention; University of Rome ‘Tor Vergata’; Rome Italy
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
| | - F. Sangiuolo
- Department of Biomedicine and Prevention; University of Rome ‘Tor Vergata’; Rome Italy
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
| | - M.R. D'Apice
- Fondazione PTV “Policlinico Tor Vergata”; U.O.C. of Medical Genetics; Rome Italy
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25
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Centronuclear myopathies: genotype-phenotype correlation and frequency of defined genetic forms in an Italian cohort. J Neurol 2015; 262:1728-40. [PMID: 25957634 DOI: 10.1007/s00415-015-7757-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/17/2015] [Accepted: 04/20/2015] [Indexed: 10/23/2022]
Abstract
Centronuclear myopathies (CNMs) are a group of clinically and genetically heterogeneous muscle disorders. To date, mutation in 7 different genes has been reported to cause CNMs but 30 % of cases still remain genetically undefined. Genetic investigations are often expensive and time consuming. Clinical and morphological clues are needed to facilitate genetic tests and to choose the best approach for genetic screening. We aimed to describe genotype-phenotype correlation in an Italian cohort of patients affected by CNMs, to define the relative frequencies of its defined genetic forms and to draw a diagnostic algorithm to address genetic investigations. We recruited patients with CNMs from all the Italian tertiary neuromuscular centers following clinical and histological criteria. All selected patients were screened for the four 'canonical' genes related to CNMs: MTM1, DNM2, RYR1 and BIN1. Pathogenetic mutations were found in 38 of the 54 screened patients (70 %), mostly in patients with congenital onset (25 of 30 patients, 83 %): 15 in MTM1, 6 in DNM2, 3 in RYR1 and one in TTN. Among the 13 patients with a childhood-adolescence onset, mutations were found in 6 patients (46 %), all in DNM2. In the group of the 11 patients with adult onset, mutations were identified in 7 patients (63 %), again in DNM2, confirming that variants in this gene are relatively more common in late-onset phenotypes. The present study provides the relative molecular frequency of centronuclear myopathy and of its genetically defined forms in Italy and also proposes a diagnostic algorithm to be used in clinical practice to address genetic investigations.
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Hunter JM, Kiefer J, Balak CD, Jooma S, Ahearn ME, Hall JG, Baumbach-Reardon L. Review of X-linked syndromes with arthrogryposis or early contractures-aid to diagnosis and pathway identification. Am J Med Genet A 2015; 167A:931-73. [DOI: 10.1002/ajmg.a.36934] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 12/05/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Jesse M. Hunter
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Jeff Kiefer
- Knowledge Mining; Translational Genomics Research Institute; Phoenix Arizona
| | - Christopher D. Balak
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Sonya Jooma
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Mary Ellen Ahearn
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
| | - Judith G. Hall
- Departments of Medical Genetics and Pediatrics; University of British Columbia and BC Children's Hospital Vancouver; British Columbia Canada
| | - Lisa Baumbach-Reardon
- Integrated Functional Cancer Genomics; Translational Genomics Research Institute; Phoenix Arizona
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Waugh MG. PIPs in neurological diseases. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1066-82. [PMID: 25680866 DOI: 10.1016/j.bbalip.2015.02.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/29/2015] [Accepted: 02/01/2015] [Indexed: 12/19/2022]
Abstract
Phosphoinositide (PIP) lipids regulate many aspects of cell function in the nervous system including receptor signalling, secretion, endocytosis, migration and survival. Levels of PIPs such as PI4P, PI(4,5)P2 and PI(3,4,5)P3 are normally tightly regulated by phosphoinositide kinases and phosphatases. Deregulation of these biochemical pathways leads to lipid imbalances, usually on intracellular endosomal membranes, and these changes have been linked to a number of major neurological diseases including Alzheimer's, Parkinson's, epilepsy, stroke, cancer and a range of rarer inherited disorders including brain overgrowth syndromes, Charcot-Marie-Tooth neuropathies and neurodevelopmental conditions such as Lowe's syndrome. This article analyses recent progress in this area and explains how PIP lipids are involved, to varying degrees, in almost every class of neurological disease. This article is part of a Special Issue entitled Brain Lipids.
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Affiliation(s)
- Mark G Waugh
- Lipid and Membrane Biology Group, Institute for Liver and Digestive Health, UCL, Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom.
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Shichiji M, Biancalana V, Fardeau M, Hogrel JY, Osawa M, Laporte J, Romero NB. Extensive morphological and immunohistochemical characterization in myotubular myopathy. Brain Behav 2013; 3:476-86. [PMID: 24381816 PMCID: PMC3869686 DOI: 10.1002/brb3.147] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 11/30/2022] Open
Abstract
The X-linked myotubular myopathy (XLMTM) also called X-linked centronuclear myopathy is a rare congenital myopathy due to mutations in the MTM 1 gene encoding myotubularin. The disease gives rise to a severe muscle weakness in males at birth. The main muscle morphological characteristics (significant number of small muscle fibers with centralized nuclei and type 1 fiber predominance) are usually documented, but the sequence of formation and maintenance of this particular morphological pattern has not been extensively characterized in humans. In this study, we perform a reevaluation of morphological changes in skeletal muscle biopsies in severe XLMTM. We correlate the pathologic features observed in the muscle biopsies of 15 newborns with MTM 1-mutations according to the "adjusted-age" at the time of muscle biopsy, focusing on sequential analysis in the early period of the life (from 34 weeks of gestation to 3 months of age). We found a similar morphological pattern throughout the period analyzed; the proportion of myofibers with central nuclei was high in all muscle biopsies, independently of the muscle type, the age of the newborns at time of biopsy and the specific MTM 1 mutation. We did not observe a period free of morphological abnormalities in human skeletal muscle as observed in myotubularin-deficient mouse models. In addition, this study demonstrated some features of delayed maturation of the muscle fibers without any increase in the number of satellite cells, associated with a marked disorganization of the muscle T-tubules and cytoskeletal network in the skeletal muscle fibers.
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Affiliation(s)
- Minobu Shichiji
- Unité de Morphologie Neuromusculaire, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France ; Department of Pediatrics, Tokyo Woman's Medical University Tokyo, Japan
| | - Valérie Biancalana
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS, UMR7104, INSERM, U964, Collège de France, Université de Strasbourg Illkirch, France ; Laboratoire Diagnostic Génétique, Faculté de Médecine - CHRU Strasbourg, France
| | - Michel Fardeau
- Unité de Morphologie Neuromusculaire, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France ; Groupe Hospitalier-Universitaire La Pitié-Salpêtrière, AP-HP, Centre de référence des maladies neuromusculaires Paris-Est, Paris, France
| | - Jean-Yves Hogrel
- UPMC-Paris6 UR76, INSERM UMR974, CNRS UMR 7215, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France
| | - Makiko Osawa
- Department of Pediatrics, Tokyo Woman's Medical University Tokyo, Japan
| | - Jocelyn Laporte
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS, UMR7104, INSERM, U964, Collège de France, Université de Strasbourg Illkirch, France
| | - Norma Beatriz Romero
- Unité de Morphologie Neuromusculaire, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France ; Groupe Hospitalier-Universitaire La Pitié-Salpêtrière, AP-HP, Centre de référence des maladies neuromusculaires Paris-Est, Paris, France ; UPMC-Paris6 UR76, INSERM UMR974, CNRS UMR 7215, Institut de Myologie GHU La Pitié-Salpêtrière, Paris, France
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Han YM, Kwon KA, Lee YJ, Nam SO, Park KH, Byun SY, Kim GH, Yoo HW. X-linked recessive myotubular myopathy with MTM1 mutations. KOREAN JOURNAL OF PEDIATRICS 2013; 56:139-42. [PMID: 23559977 PMCID: PMC3611049 DOI: 10.3345/kjp.2013.56.3.139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/16/2012] [Accepted: 08/02/2012] [Indexed: 11/27/2022]
Abstract
X-linked recessive myotubular myopathy (XLMTM) is a severe congenital muscle disorder caused by mutations in the MTM1 gene and characterized by severe hypotonia and generalized muscle weakness in affected males. It is generally a fatal disorder during the neonatal period and early infancy. The diagnosis is based on typical histopathological findings on muscle biopsy, combined with suggestive clinical features. We experienced a case of a newborn who required intubation and ventilator care because of profound hypotonia and respiratory difficulty. The preliminary diagnosis at the time of request for retrieval was hypoxic ischemic encephalopathy, but the infant was clinically reevaluated for generalized weakness and muscle atrophy. Muscle biopsies showed variability in fiber size and centrally located nuclei in nearly all the fibers. We detected an MTM1 gene mutation of c.1261-1C>A in the intron 10 region, and diagnosed the neonate with myotubular myopathy. The same mutation was detected in his mother.
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Affiliation(s)
- Young-Mi Han
- Department of Pediatrics, Pusan National University School of Medicine, Yangsan, Korea
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Amburgey K, Lawlor MW, Del Gaudio D, Cheng YW, Fitzpatrick C, Minor A, Li X, Aughton D, Das S, Beggs AH, Dowling JJ. Large duplication in MTM1 associated with myotubular myopathy. Neuromuscul Disord 2012; 23:214-8. [PMID: 23273872 DOI: 10.1016/j.nmd.2012.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 10/23/2012] [Accepted: 11/23/2012] [Indexed: 11/26/2022]
Abstract
Myotubular myopathy is a subtype of centronuclear myopathy with X-linked inheritance and distinctive clinical and pathologic features. Most boys with myotubular myopathy have MTM1 mutations. In remaining individuals, it is not clear if disease is due to an undetected alteration in MTM1 or mutation of another gene. We describe a boy with myotubular myopathy but without mutation in MTM1 by conventional sequencing. Array-CGH analysis of MTM1 uncovered a large MTM1 duplication. This finding suggests that at least some unresolved cases of myotubular myopathy are due to duplications in MTM1, and that array-CGH should be considered when MTM1 sequencing is unrevealing.
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Affiliation(s)
- K Amburgey
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
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31
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Amoasii L, Bertazzi DL, Tronchère H, Hnia K, Chicanne G, Rinaldi B, Cowling BS, Ferry A, Klaholz B, Payrastre B, Laporte J, Friant S. Phosphatase-dead myotubularin ameliorates X-linked centronuclear myopathy phenotypes in mice. PLoS Genet 2012; 8:e1002965. [PMID: 23071445 PMCID: PMC3469422 DOI: 10.1371/journal.pgen.1002965] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 08/08/2012] [Indexed: 12/27/2022] Open
Abstract
Myotubularin MTM1 is a phosphoinositide (PPIn) 3-phosphatase mutated in X-linked centronuclear myopathy (XLCNM; myotubular myopathy). We investigated the involvement of MTM1 enzymatic activity on XLCNM phenotypes. Exogenous expression of human MTM1 in yeast resulted in vacuolar enlargement, as a consequence of its phosphatase activity. Expression of mutants from patients with different clinical progression and determination of PtdIns3P and PtdIns5P cellular levels confirmed the link between vacuolar morphology and MTM1 phosphatase activity, and showed that some disease mutants retain phosphatase activity. Viral gene transfer of phosphatase-dead myotubularin mutants (MTM1(C375S) and MTM1(S376N)) significantly improved most histological signs of XLCNM displayed by a Mtm1-null mouse, at similar levels as wild-type MTM1. Moreover, the MTM1(C375S) mutant improved muscle performance and restored the localization of nuclei, triad alignment, and the desmin intermediate filament network, while it did not normalize PtdIns3P levels, supporting phosphatase-independent roles of MTM1 in maintaining normal muscle performance and organelle positioning in skeletal muscle. Among the different XLCNM signs investigated, we identified only triad shape and fiber size distribution as being partially dependent on MTM1 phosphatase activity. In conclusion, this work uncovers MTM1 roles in the structural organization of muscle fibers that are independent of its enzymatic activity. This underlines that removal of enzymes should be used with care to conclude on the physiological importance of their activity.
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MESH Headings
- Animals
- Desmin/metabolism
- Disease Models, Animal
- Enzyme Activation/genetics
- Gene Expression
- Humans
- Male
- Mice
- Mice, Knockout
- Muscle Strength/genetics
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/ultrastructure
- Mutation
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/metabolism
- Phenotype
- Phosphatidylinositol Phosphates/metabolism
- Phosphoric Monoester Hydrolases/metabolism
- Protein Tyrosine Phosphatases, Non-Receptor/genetics
- Protein Tyrosine Phosphatases, Non-Receptor/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
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Affiliation(s)
- Leonela Amoasii
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Illkirch, France
| | - Dimitri L. Bertazzi
- Department of Molecular and Cellular Genetics, UMR7156, Université de Strasbourg and CNRS, Strasbourg, France
| | | | - Karim Hnia
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Illkirch, France
| | - Gaëtan Chicanne
- INSERM, U1048 and Université Toulouse 3, I2MC, Toulouse, France
| | - Bruno Rinaldi
- Department of Molecular and Cellular Genetics, UMR7156, Université de Strasbourg and CNRS, Strasbourg, France
| | - Belinda S. Cowling
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Illkirch, France
| | - Arnaud Ferry
- UMRS974, Université Pierre et Marie Curie, Paris, France
| | - Bruno Klaholz
- Department of Integrated Structural Biology, IGBMC, INSERM U964, CNRS UMR7104, Université de Strasbourg, Illkirch, France
| | - Bernard Payrastre
- INSERM, U1048 and Université Toulouse 3, I2MC, Toulouse, France
- CHU de Toulouse, Laboratoire d'Hématologie, Toulouse, France
- * E-mail: (SF); (JL); (BP)
| | - Jocelyn Laporte
- Department of Translational Medecine, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, Université de Strasbourg, Collège de France, Illkirch, France
- * E-mail: (SF); (JL); (BP)
| | - Sylvie Friant
- Department of Molecular and Cellular Genetics, UMR7156, Université de Strasbourg and CNRS, Strasbourg, France
- * E-mail: (SF); (JL); (BP)
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Oliveira J, Oliveira ME, Kress W, Taipa R, Pires MM, Hilbert P, Baxter P, Santos M, Buermans H, den Dunnen JT, Santos R. Expanding the MTM1 mutational spectrum: novel variants including the first multi-exonic duplication and development of a locus-specific database. Eur J Hum Genet 2012; 21:540-9. [PMID: 22968136 DOI: 10.1038/ejhg.2012.201] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Myotubular myopathy (MIM#310400), the X-linked form of Centronuclear myopathy (CNM) is mainly characterized by neonatal hypotonia and inability to maintain unassisted respiration. The MTM1 gene, responsible for this disease, encodes myotubularin - a lipidic phosphatase involved in vesicle trafficking regulation and maturation. Recently, it was shown that myotubularin interacts with desmin, being a major regulator of intermediate filaments. We report the development of a locus-specific database for MTM1 using the Leiden Open Variation database software (http://www.lovd.nl/MTM1), with data collated for 474 mutations identified in 472 patients (by June 2012). Among the entries are a total of 25 new mutations, including a large deletion encompassing introns 2-15. During database implementation it was noticed that no large duplications had been reported. We tested a group of eight uncharacterized CNM patients for this specific type of mutation, by multiple ligation-dependent probe amplification (MLPA) analysis. A large duplication spanning exons 1-5 was identified in a boy with a mild phenotype, with results pointing toward possible somatic mosaicism. Further characterization revealed that this duplication causes an in-frame deletion at the mRNA level (r.343_444del). Results obtained with a next generation sequencing approach suggested that the duplication extends into the neighboring MAMLD1 gene and subsequent cDNA analysis detected the presence of a MTM1/MAMLD1 fusion transcript. A complex rearrangement involving the duplication of exon 10 has since been reported, with detection also enabled by MLPA analysis. It is thus conceivable that large duplications in MTM1 may account for a number of CNM cases that have remained genetically unresolved.
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Affiliation(s)
- Jorge Oliveira
- Unidade de Investigação e Desenvolvimento, Departamento de Genética, Centro de Genética Médica Dr Jacinto Magalhães, Instituto Nacional de Saúde Dr Ricardo Jorge, IP, Porto, Portugal
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Biancalana V, Beggs AH, Das S, Jungbluth H, Kress W, Nishino I, North K, Romero NB, Laporte J. Clinical utility gene card for: Centronuclear and myotubular myopathies. Eur J Hum Genet 2012; 20:ejhg201291. [PMID: 22617344 DOI: 10.1038/ejhg.2012.91] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Valérie Biancalana
- Laboratoire de Diagnostic Génétique, Faculté de Médecine-CHRU, 1 place de l'Hôpital, Strasbourg, France.
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Gurgel-Giannetti J, Zanoteli E, de Castro Concentino EL, Abath Neto O, Pesquero JB, Reed UC, Vainzof M. Necklace fibers as histopathological marker in a patient with severe form of X-linked myotubular myopathy. Neuromuscul Disord 2012; 22:541-5. [PMID: 22264517 DOI: 10.1016/j.nmd.2011.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 11/13/2011] [Accepted: 12/16/2011] [Indexed: 10/14/2022]
Abstract
X-linked myotubular myopathy due to mutations in the MTM1 gene is classically characterized by a severe neonatal phenotype and a typical muscle biopsy presenting globular and centrally located nuclei in muscle myofibers. Recently, four patients with mild late-onset form have been described, a male with a hemizygous mutation and three females with heterozygous mutations in the MTM1 gene. The muscle biopsies were performed at 13-35 years of age and a new histological marker, the necklace fibers, was described. Here, we report two siblings with the pathogenic c.664 C>T mutation in the MTM1 gene, presenting a severe muscle weakness and respiratory impairment requiring ventilatory support since the first months of life until death, at the age of 36 months and 5 months. In the older brother the muscle biopsy, performed at the age of 30 months, showed almost 100% of necklace fibers, which were not present in the younger one submitted to muscle biopsy at 5 months of age. Our findings confirm the necklace fibers can be a histopathological finding of MTM1 myopathies, even in the severe neonatal form, and suggest that the necklace fibers appear or increase in number over time.
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35
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Sewry CA, Quinlivan RCM, Squier W, Morris GE, Holt I. A rapid immunohistochemical test to distinguish congenital myotonic dystrophy from X-linked myotubular myopathy. Neuromuscul Disord 2011; 22:225-30. [PMID: 22113158 DOI: 10.1016/j.nmd.2011.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/05/2011] [Accepted: 10/05/2011] [Indexed: 12/11/2022]
Abstract
Severe forms of myotubular myopathy (MTM) and congenital myotonic dystrophy type 1 (CDM), both present as floppy infants with hypotonia, respiratory failure and bulbar insufficiency. Muscle biopsy is often performed as part of the diagnostic process, but these two disorders share very similar histopathological features. It is well documented that CDM muscle has nuclear foci that contain muscleblind-like 1 (MBNL1) protein. In muscle biopsies from eight neonates showing central nuclei, MBNL1 immunolocalisation identified discrete, intensely stained foci in three cases that were subsequently confirmed as CDM by DNA analysis. In the five remaining non-CDM patients and two controls, MBNL1 staining was heterogeneous in nuclei, not as foci. MBNL1 staining patterns in CDM were easily distinguishable from MTM. We suggest that in cases of hypotonia with suspected CDM or MTM, when biopsy has been taken, sections should additionally be stained for MBNL1 to provide a rapid indication of a CDM diagnosis.
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Affiliation(s)
- Caroline A Sewry
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital NHS Foundation Trust, Oswestry, Shropshire SY10 7AG, UK
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36
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Protein tyrosine phosphatase-like A regulates myoblast proliferation and differentiation through MyoG and the cell cycling signaling pathway. Mol Cell Biol 2011; 32:297-308. [PMID: 22106411 DOI: 10.1128/mcb.05484-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Protein tyrosine phosphatase-like A (PTPLa) has been implicated in skeletal myogenesis and cardiogenesis. Mutations in PTPLa correlated with arrhythmogenic right ventricular dysplasia in humans and congenital centronuclear myopathy with severe hypotonia in dogs. The molecular mechanisms of PTPLa in myogenesis are unknown. In this report, we demonstrate that PTPLa is required for myoblast growth and differentiation. The cells lacking PTPLa remained immature and failed to differentiate into mature myotubes. The repressed MyoG expression was responsible for the impaired myoblast differentiation. Meanwhile, impeded cell growth, with an obvious S-phase arrest and compromised G(2)/M transition, was observed in PTPLa-deficient myoblasts. Further study demonstrated that the upregulation of cyclin D1 and cyclin E2 complexes, along with a compromised G(2)/M transition due to the decreased CDK1 (cyclin-dependent kinase 1) activity and upregulated p21, contributed to the mutant cell S-phase arrest and eventually led to the retarded cell growth. Finally, the transcriptional regulation of the PTPLa gene was explored. We identified PTPLa as a new target gene of the serum response factor (SRF). Skeletal- and cardiac-muscle-specific SRF knockouts resulted in significant decreases in PTPLa expression, suggesting a conserved transcriptional regulation of the PTPLa gene in mice.
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37
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Pierson CR, Dulin-Smith AN, Durban AN, Marshall ML, Marshall JT, Snyder AD, Naiyer N, Gladman JT, Chandler DS, Lawlor MW, Buj-Bello A, Dowling JJ, Beggs AH. Modeling the human MTM1 p.R69C mutation in murine Mtm1 results in exon 4 skipping and a less severe myotubular myopathy phenotype. Hum Mol Genet 2011; 21:811-25. [PMID: 22068590 DOI: 10.1093/hmg/ddr512] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
X-linked myotubular myopathy (MTM) is a severe neuromuscular disease of infancy caused by mutations of MTM1, which encodes the phosphoinositide lipid phosphatase, myotubularin. The Mtm1 knockout (KO) mouse has a severe phenotype and its short lifespan (8 weeks) makes it a challenge to use as a model in the testing of certain preclinical therapeutics. Many MTM patients succumb early in life, but some have a more favorable prognosis. We used human genotype-phenotype correlation data to develop a myotubularin-deficient mouse model with a less severe phenotype than is seen in Mtm1 KO mice. We modeled the human c.205C>T point mutation in Mtm1 exon 4, which is predicted to introduce the p.R69C missense change in myotubularin. Hemizygous male Mtm1 p.R69C mice develop early muscle atrophy prior to the onset of weakness at 2 months. The median survival period is 66 weeks. Histopathology shows small myofibers with centrally placed nuclei. Myotubularin protein is undetectably low because the introduced c.205C>T base change induced exon 4 skipping in most mRNAs, leading to premature termination of myotubularin translation. Some full-length Mtm1 mRNA bearing the mutation is present, which provides enough myotubularin activity to account for the relatively mild phenotype, as Mtm1 KO and Mtm1 p.R69C mice have similar muscle phosphatidylinositol 3-phosphate levels. These data explain the basis for phenotypic variability among human patients with MTM1 p.R69C mutations and establish the Mtm1 p.R69C mouse as a valuable model for the disease, as its less severe phenotype will expand the scope of testable preclinical therapies.
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Wen P, Osborne S, Meunier F. Dynamic control of neuroexocytosis by phosphoinositides in health and disease. Prog Lipid Res 2011; 50:52-61. [DOI: 10.1016/j.plipres.2010.08.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/02/2010] [Indexed: 10/19/2022]
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39
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Novel molecular diagnostic approaches for X-linked centronuclear (myotubular) myopathy reveal intronic mutations. Neuromuscul Disord 2010; 20:375-81. [DOI: 10.1016/j.nmd.2010.03.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 02/20/2010] [Accepted: 03/30/2010] [Indexed: 11/21/2022]
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Abstract
The process of sexual differentiation is central for reproduction of almost all metazoan, and therefore, for maintenance of practically all multicellular organisms. In sex development, we can distinguish two different processes, sex determination, that is the developmental decision that directs the undifferentiated embryo into a sexually dimorphic individual. In mammals, sex determination equals gonadal development. The second process known as sex differentiation takes place once the sex determination decision has been made through factors produced by the gonads that determine the development of the phenotypic sex. Most of the knowledge on the factors involved in sexual development came from animal models and from studies of cases in whom the genetic or the gonadal sex does not match the phenotypical sex, that is, patients affected by disorders of sex development (DSDs). Generally speaking, factors influencing sex determination are transcriptional regulators, whereas factors important for sex differentiation are secreted hormones and their receptors. This review focuses on these factors and whenever possible, references regarding the 'prismatic' clinical cases are given.
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Affiliation(s)
- Anna Biason-Lauber
- Division of Endocrinology/Diabetology, University Children's Hospital, Steinwiesstrasse 75, CH-8032 Zurich, Switzerland.
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Chen JM, Férec C, Cooper DN. Closely spaced multiple mutations as potential signatures of transient hypermutability in human genes. Hum Mutat 2009; 30:1435-48. [PMID: 19685533 DOI: 10.1002/humu.21088] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Data from diverse organisms suggests that transient hypermutability is a general mutational mechanism with the potential to generate multiple synchronous mutations, a phenomenon probably best exemplified by closely spaced multiple mutations (CSMMs). Here we have attempted to extend the concept of transient hypermutability from somatic cells to the germline, using human inherited disease-causing multiple mutations as a model system. Employing stringent criteria for data inclusion, we have retrospectively identified numerous potential examples of pathogenic CSMMs that exhibit marked similarities to the CSMMs reported in other systems. These examples include (1) eight multiple mutations, each comprising three or more components within a sequence tract of <100 bp; (2) three possible instances of "mutation showers"; and (3) numerous highly informative "homocoordinate" mutations. Using the proportion of CpG substitution as a crude indicator of the relative likelihood of transient hypermutability, we present evidence to suggest that CSMMs comprising at least one pair of mutations separated by < or =100 bp may constitute signatures of transient hypermutability in human genes. Although this analysis extends the generality of the concept of transient hypermutability and provides new insights into what may be considered a novel mechanism of mutagenesis underlying human inherited disease, it has raised serious concerns regarding current practices in mutation screening.
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Affiliation(s)
- Jian-Min Chen
- Institut National de la Santé et de la Recherche Médicale, U613, Brest, France.
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43
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Sharma MC, Jain D, Sarkar C, Goebel HH. Congenital myopathies--a comprehensive update of recent advancements. Acta Neurol Scand 2009; 119:281-92. [PMID: 19133863 DOI: 10.1111/j.1600-0404.2008.01126.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The congenital myopathies are relatively newly discovered compared with other categories of muscle diseases. Current research continues to clarify and classify the congenital myopathies. These pose a diagnostic problem and cannot be diagnosed by routine hematoxylin and eosin stain. A lot of special techniques are required to diagnose them correctly and it's various subtypes. The disease specific structural changes seen in the muscle are detected by enzyme histochemistry, immunohistochemistry and electron microscopy. Through this review we provide an up-to-date analysis of congenital myopathies including clinical and pathologic aspects.
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Affiliation(s)
- M C Sharma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India.
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Bevilacqua JA, Bitoun M, Biancalana V, Oldfors A, Stoltenburg G, Claeys KG, Lacène E, Brochier G, Manéré L, Laforêt P, Eymard B, Guicheney P, Fardeau M, Romero NB. "Necklace" fibers, a new histological marker of late-onset MTM1-related centronuclear myopathy. Acta Neuropathol 2009; 117:283-91. [PMID: 19084976 DOI: 10.1007/s00401-008-0472-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 12/02/2008] [Accepted: 12/03/2008] [Indexed: 12/31/2022]
Abstract
Mutations in the gene encoding the phosphoinositide phosphatase myotubularin 1 protein (MTM1) are usually associated with severe neonatal X-linked myotubular myopathy (XLMTM). However, mutations in MTM1 have also been recognized as the underlying cause of "atypical" forms of XLMTM in newborn boys, female infants, female manifesting carriers and adult men. We reviewed systematically the biopsies of a cohort of patients with an unclassified form of centronuclear myopathy (CNM) and identified four patients presenting a peculiar histological alteration in some muscle fibers that resembled a necklace ("necklace fibers"). We analyzed further the clinical and morphological features and performed a screening of the genes involved in CNM. Muscle biopsies in all four patients demonstrated 4-20% of fibers with internalized nuclei aligned in a basophilic ring (necklace) at 3 microm beneath the sarcolemma. Ultrastructurally, such necklaces consisted of myofibrils of smaller diameter, in oblique orientation, surrounded by mitochondria, sarcoplasmic reticulum and glycogen granules. In the four patients (three women and one man), myopathy developed in early childhood but was slowly progressive. All had mutations in the MTM1 gene. Two mutations have previously been reported (p.E404K and p.R241Q), while two are novel; a c.205_206delinsAACT frameshift change in exon 4 and a c.1234A>G mutation in exon 11 leading to an abnormal splicing and the deletion of nine amino acids in the catalytic domain of MTM1. Necklace fibers were seen neither in DNM2- or BIN1-related CNM nor in males with classical XLMTM. The presence of necklace fibers is useful as a marker to direct genetic analysis to MTM1 in CNM.
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MESH Headings
- Adolescent
- Adult
- Age of Onset
- Biopsy
- Female
- Humans
- Immunohistochemistry
- Magnetic Resonance Imaging
- Male
- Microscopy, Electron
- Middle Aged
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal/pathology
- Muscle, Skeletal/ultrastructure
- Mutation
- Myofibrils/ultrastructure
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/metabolism
- Myopathies, Structural, Congenital/pathology
- Polymerase Chain Reaction
- Protein Tyrosine Phosphatases, Non-Receptor/genetics
- Protein Tyrosine Phosphatases, Non-Receptor/metabolism
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Affiliation(s)
- Jorge A Bevilacqua
- INSERM, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
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45
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Jungbluth H, Wallgren-Pettersson C, Laporte J. Centronuclear (myotubular) myopathy. Orphanet J Rare Dis 2008; 3:26. [PMID: 18817572 PMCID: PMC2572588 DOI: 10.1186/1750-1172-3-26] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Accepted: 09/25/2008] [Indexed: 01/23/2023] Open
Abstract
Centronuclear myopathy (CNM) is an inherited neuromuscular disorder characterised by clinical features of a congenital myopathy and centrally placed nuclei on muscle biopsy. The incidence of X-linked myotubular myopathy is estimated at 2/100000 male births but epidemiological data for other forms are not currently available. The clinical picture is highly variable. The X-linked form usually gives rise to a severe phenotype in males presenting at birth with marked weakness and hypotonia, external ophthalmoplegia and respiratory failure. Signs of antenatal onset comprise reduced foetal movements, polyhydramnios and thinning of the ribs on chest radiographs; birth asphyxia may be the present. Affected infants are often macrosomic, with length above the 90th centile and large head circumference. Testes are frequently undescended. Both autosomal-recessive (AR) and autosomal-dominant (AD) forms differ from the X-linked form regarding age at onset, severity, clinical characteristics and prognosis. In general, AD forms have a later onset and milder course than the X-linked form, and the AR form is intermediate in both respects. Mutations in the myotubularin (MTM1) gene on chromosome Xq28 have been identified in the majority of patients with the X-linked recessive form, whilst AD and AR forms have been associated with mutations in the dynamin 2 (DNM2) gene on chromosome 19p13.2 and the amphiphysin 2 (BIN1) gene on chromosome 2q14, respectively. Single cases with features of CNM have been associated with mutations in the skeletal muscle ryanodine receptor (RYR1) and the hJUMPY (MTMR14) genes. Diagnosis is based on typical histopathological findings on muscle biopsy in combination with suggestive clinical features; muscle magnetic resonance imaging may complement clinical assessment and inform genetic testing in cases with equivocal features. Genetic counselling should be offered to all patients and families in whom a diagnosis of CNM has been made. The main differential diagnoses include congenital myotonic dystrophy and other conditions with severe neonatal hypotonia. Management of CNM is mainly supportive, based on a multidisciplinary approach. Whereas the X-linked form due to MTM1 mutations is often fatal in infancy, dominant forms due to DNM2 mutations and some cases of the recessive BIN1-related form appear to be associated with an overall more favourable prognosis.
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Affiliation(s)
- Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, St Thomas' Hospital, London, UK.
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Kalfa N, Philibert P, Sultan C. Is hypospadias a genetic, endocrine or environmental disease, or still an unexplained malformation? ACTA ACUST UNITED AC 2008; 32:187-97. [PMID: 18637150 DOI: 10.1111/j.1365-2605.2008.00899.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hypospadias is one of the most frequent genital malformations in the male newborn and results from an abnormal penile and urethral development. This process requires a correct genetic programme, time- and space-adapted cellular differentiation, complex tissue interactions, and hormonal mediation through enzymatic activities and hormonal transduction signals. Any disturbance in these regulations may induce a defect in the virilization of the external genitalia and hypospadias. This malformation thus appears to be at the crossroads of various mechanisms implicating genetic and environmental factors. The genes of penile development (HOX, FGF, Shh) and testicular determination (WT1, SRY) and those regulating the synthesis [luteinizing hormone (LH) receptor] and action of androgen (5alpha reductase, androgen receptor) can cause hypospadias if altered. Several chromosomal abnormalities and malformative syndromes include hypospadias, from anterior to penoscrotal forms. More recently, CXorf6 and ATF3 have been reported to be involved. Besides these genomic and hormonal factors, multiple substances found in the environment can also potentially interfere with male genital development because of their similarity to hormones. The proportion of hypospadias cases for which an aetiology is detected varies with the authors but it nevertheless remains low, especially for less severe cases. An interaction between genetic background and environment is likely.
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47
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Kundu M, Thompson CB. Autophagy: basic principles and relevance to disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:427-55. [PMID: 18039129 DOI: 10.1146/annurev.pathmechdis.2.010506.091842] [Citation(s) in RCA: 410] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Autophagy is a process by which cytoplasmic components are sequestered in double membrane vesicles and degraded upon fusion with lysosomal compartments. In yeast, autophagy is activated in response to changes in the extracellular milieu. Depending upon the stimulus, autophagy can degrade cytoplasmic contents nonspecifically or can target the degradation of specific cellular components. Both of these have been adopted in higher eukaryotes and account for the expanding role of autophagy in various cellular processes, as well as contribute to the variation in cellular outcomes after induction of autophagy. In some cases, autophagy appears to be an adaptive response, whereas under other circumstances it is involved in cell death. In mammals, autophagy has been implicated in either the pathogenesis or response to a wide variety of diseases, including neurodegenerative disease, chronic bacterial and viral infections, atherosclerosis, and cancer. As the basic molecular pathways that regulate autophagy are elucidated, the relationship of autophagy to the pathogenesis of various disease states emerges.
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Affiliation(s)
- Mondira Kundu
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19063, USA.
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48
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Ogata T, Fukami M, Wada Y. MAMLD1 (CXorf6) is a New Gene for Hypospadias. Clin Pediatr Endocrinol 2008; 17:87-93. [PMID: 24790369 PMCID: PMC4004825 DOI: 10.1297/cpe.17.87] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Accepted: 07/18/2008] [Indexed: 11/29/2022] Open
Abstract
MAMLD1 (mastermind-like domain containing 1), previously known as CXorf6
(chromosome X open reading frame 6), has been shown to be a causative gene for
hypospadias. This is primarily based on the identification of nonsense mutations (E124X,
Q197X, and R653X), which undergo nonsense mediated mRNA decay, in patients with
penoscrotal hypospadias. Subsequent molecular studies have shown that the mouse homolog is
transiently expressed in fetal Sertoli and Leydig cells around the critical period for sex
development, and that transient knockdown of Mamld1 results in significantly reduced
testosterone production in murine Leydig tumor cells. These findings suggest that the
MAMLD1 mutations cause hypospadias primarily because of compromised testosterone
production around the critical period for sex development.
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Affiliation(s)
- Tsutomu Ogata
- Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Maki Fukami
- Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Yuka Wada
- Department of Endocrinology and Metabolism, National Research Institute for Child Health and Development, Tokyo, Japan
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Abstract
PURPOSE OF REVIEW The aim of this review is to provide an up-to-date personal analysis of current congenital myopathy research. RECENT FINDINGS In the past year novel congenital myopathies have been suggested, genes have been discovered for some of the congenital myopathies for the first time (beta-tropomyosin in cap disease and perhaps skeletal muscle alpha-actin in Zebra body myopathy), further genes have been identified for congenital myopathies where other genes had already been found (cofilin in nemaline myopathy, selenoprotein N in congenital fibre type disproportion) and recessive myosin storage myopathy was associated with homozygous mutation of slow-skeletal/beta-cardiac myosin which was already known to be mutated in dominant myosin storage myopathy. There has been further clarification of the pathobiology of the congenital myopathies, including determination of the basis of epigenetic effects: silencing of the normal allele in recessive central core disease and persistence of cardiac (fetal) alpha-actin in nemaline myopathy patients with no skeletal actin. SUMMARY The increased understanding of the genes and pathobiology of the congenital myopathies that is developing should ultimately lead to effective treatments.
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Affiliation(s)
- Nigel G Laing
- Centre for Medical Research, University of Western Australia and Western Australian Institute for Medical Research, Nedlands, Western Australia, Australia.
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Cao C, Laporte J, Backer JM, Wandinger-Ness A, Stein MP. Myotubularin lipid phosphatase binds the hVPS15/hVPS34 lipid kinase complex on endosomes. Traffic 2007; 8:1052-67. [PMID: 17651088 DOI: 10.1111/j.1600-0854.2007.00586.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Myotubularins constitute a ubiquitous family of phosphatidylinositol (PI) 3-phosphatases implicated in several neuromuscular disorders. Myotubularin [myotubular myopathy 1 (MTM1)] PI 3-phosphatase is shown associated with early and late endosomes. Loss of endosomal phosphatidylinositol 3-phosphate [PI(3)P] upon overexpression of wild-type MTM1, but not a phosphatase-dead MTM1C375S mutant, resulted in altered early and late endosomal PI(3)P levels and rapid depletion of early endosome antigen-1. Membrane-bound MTM1 was directly complexed to the hVPS15/hVPS34 [vacuolar protein sorting (VPS)] PI 3-kinase complex with binding mediated by the WD40 domain of the hVPS15 (p150) adapter protein and independent of a GRAM-domain point mutation that blocks PI(3,5)P(2) binding. The WD40 domain of hVPS15 also constitutes the binding site for Rab7 and, as shown previously, contributes to Rab5 binding. In vivo, the hVPS15/hVPS34 PI 3-kinase complex forms mutually exclusive complexes with the Rab GTPases (Rab5 or Rab7) or with MTM1, suggesting a competitive binding mechanism. Thus, the Rab GTPases together with MTM1 likely serve as molecular switches for controlling the sequential synthesis and degradation of endosomal PI(3)P. Normal levels of endosomal PI(3)P and PI(3,5)P(2) are crucial for both endosomal morphology and function, suggesting that disruption of endosomal sorting and trafficking in skeletal muscle when MTM1 is mutated may be a key factor in precipitating X-linked MTM.
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Affiliation(s)
- Canhong Cao
- Molecular Trafficking Laboratory, Department of Pathology, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
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