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Sun YQ, Lv Q, Chen D, Da Y, Zhao XY, Dong JZ. A Case Study and Literature Review of the Diagnosis of Danon Disease in Patients Presenting Only with Severe Cardiac Symptoms. Pharmgenomics Pers Med 2023; 16:767-775. [PMID: 37609033 PMCID: PMC10441658 DOI: 10.2147/pgpm.s392800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 08/01/2023] [Indexed: 08/24/2023] Open
Abstract
The clinical manifestations of Danon disease, which result from the primary deficiency of the lysosome-associated membrane protein 2 gene, include cardiomyopathy, skeletal myopathy, and different degrees of intellectual disability that vary greatly among patients. The present study reports on two cases of Danon disease in two patients who only presented cardiac symptoms. Cardiac symptoms usually occur in adolescence and during a patient's twenties, and most patients die from heart failure. However, the lab results from these cases suggested that other systems were involved, despite no other clinical symptoms. Significantly, the two patients had elevated serum cardiac troponin I, which often manifests in the acute cardiac phase, especially in severely affected patients with rapidly fatal outcomes. Danon disease is a multi-system involvement disease. Therefore, clinicians must be aware of its complexity when evaluating newly diagnosed patients due to its vastly different clinical course and prognosis and the importance of multidisciplinary management.
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Affiliation(s)
- Yu-Qing Sun
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung & Blood Vessel Diseases, Beijing, People’s Republic of China
| | - Qiang Lv
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung & Blood Vessel Diseases, Beijing, People’s Republic of China
| | - Dong Chen
- Department of Pathology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung & Blood Vessel Diseases, Beijing, People’s Republic of China
| | - Yuwei Da
- Department of Neurology, Beijing Xuanwu Hospital, Capital Medical University, Beijing, People’s Republic of China
| | - Xiao-Yan Zhao
- Department of Cardiology, The First Affiliated Hospital, Zhengzhou University, Zhengzhou, Henan, People’s Republic of China
| | - Jian-Zeng Dong
- Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung & Blood Vessel Diseases, Beijing, People’s Republic of China
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Conte F, Sam JE, Lefeber DJ, Passier R. Metabolic Cardiomyopathies and Cardiac Defects in Inherited Disorders of Carbohydrate Metabolism: A Systematic Review. Int J Mol Sci 2023; 24:ijms24108632. [PMID: 37239976 DOI: 10.3390/ijms24108632] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/25/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
Heart failure (HF) is a progressive chronic disease that remains a primary cause of death worldwide, affecting over 64 million patients. HF can be caused by cardiomyopathies and congenital cardiac defects with monogenic etiology. The number of genes and monogenic disorders linked to development of cardiac defects is constantly growing and includes inherited metabolic disorders (IMDs). Several IMDs affecting various metabolic pathways have been reported presenting cardiomyopathies and cardiac defects. Considering the pivotal role of sugar metabolism in cardiac tissue, including energy production, nucleic acid synthesis and glycosylation, it is not surprising that an increasing number of IMDs linked to carbohydrate metabolism are described with cardiac manifestations. In this systematic review, we offer a comprehensive overview of IMDs linked to carbohydrate metabolism presenting that present with cardiomyopathies, arrhythmogenic disorders and/or structural cardiac defects. We identified 58 IMDs presenting with cardiac complications: 3 defects of sugar/sugar-linked transporters (GLUT3, GLUT10, THTR1); 2 disorders of the pentose phosphate pathway (G6PDH, TALDO); 9 diseases of glycogen metabolism (GAA, GBE1, GDE, GYG1, GYS1, LAMP2, RBCK1, PRKAG2, G6PT1); 29 congenital disorders of glycosylation (ALG3, ALG6, ALG9, ALG12, ATP6V1A, ATP6V1E1, B3GALTL, B3GAT3, COG1, COG7, DOLK, DPM3, FKRP, FKTN, GMPPB, MPDU1, NPL, PGM1, PIGA, PIGL, PIGN, PIGO, PIGT, PIGV, PMM2, POMT1, POMT2, SRD5A3, XYLT2); 15 carbohydrate-linked lysosomal storage diseases (CTSA, GBA1, GLA, GLB1, HEXB, IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, ARSB, GUSB, ARSK). With this systematic review we aim to raise awareness about the cardiac presentations in carbohydrate-linked IMDs and draw attention to carbohydrate-linked pathogenic mechanisms that may underlie cardiac complications.
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Affiliation(s)
- Federica Conte
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Department of Applied Stem Cell Technologies, TechMed Centre, University of Twente, 7522 NH Enschede, The Netherlands
| | - Juda-El Sam
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Dirk J Lefeber
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Robert Passier
- Department of Applied Stem Cell Technologies, TechMed Centre, University of Twente, 7522 NH Enschede, The Netherlands
- Department of Anatomy and Embryology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
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Xu J, Li Z, Liu Y, Zhang X, Niu F, Zheng H, Wang L, Kang L, Wang K, Xu B. Danon disease: a case report and literature review. Diagn Pathol 2021; 16:39. [PMID: 33933120 PMCID: PMC8088694 DOI: 10.1186/s13000-021-01100-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 04/15/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Danon disease (DD) is a rare x-linked dominant multisystemic disorder with a clinical triad of severe cardiomyopathy, skeletal myopathy, and mental retardation. It is caused by a defect in the lysosomal-associated membrane protein-2 (LAMP2) gene, which leads to the formation of autophagic vacuoles containing glycogen granule deposits in skeletal and cardiac muscle fibers. So far, more than 50 different mutations in LAMP2 have been identified. CASE PRESENTATION Here, we report an 18-year-old male patient who was hospitalized for heart failure. Biopsy of the left lateral femoral muscle revealed scattered autophagic vacuoles in the muscle fibers with increased glycogen. Next generation sequencing (NGS) was used to detect gene mutations of the proband sample and a novel frameshift mutation (c.1052delG) has been identified in exon 8 of LAMP2, which leads to truncation of the protein. CONCLUSION We found a novel frameshift mutation, a hemizygous mutation (c.1052delG) in exon 8 of LAMP2, identified as presenting the hypertrophic cardiomyopathy (HCM) phenotype. Genetic analysis is the gold standard for the diagnosis of DD and is essential to determine appropriate treatment strategies and to confirm the genetic risk of family members.
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Affiliation(s)
- Jiamin Xu
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China
| | - Zhu Li
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China
| | - Yihai Liu
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China
| | - Xinlin Zhang
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China
| | - Fengnan Niu
- Department of Pathology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China
| | - Hongyan Zheng
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China
| | - Lian Wang
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China
| | - Lina Kang
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China.
| | - Kun Wang
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China.
| | - Biao Xu
- Department of Cardiology, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, 210008, P.R. China.
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Cenacchi G, Papa V, Pegoraro V, Marozzo R, Fanin M, Angelini C. Review: Danon disease: Review of natural history and recent advances. Neuropathol Appl Neurobiol 2019; 46:303-322. [DOI: 10.1111/nan.12587] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/02/2019] [Indexed: 12/16/2022]
Affiliation(s)
- G. Cenacchi
- Department of Biomedical and Neuromotor Sciences “Alma Mater” University of Bologna Bologna Italy
| | - V. Papa
- Department of Biomedical and Neuromotor Sciences “Alma Mater” University of Bologna Bologna Italy
| | - V. Pegoraro
- Neurobiology Laboratory IRCCS San Camillo Hospital VeniceItaly
| | - R. Marozzo
- Neurobiology Laboratory IRCCS San Camillo Hospital VeniceItaly
| | - M. Fanin
- Department of Neurosciences University of Padova Padova Italy
| | - C. Angelini
- Neuromuscular Department IRCCS San Camillo Hospital Venice Italy
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Kuroda K, Seguchi O, Matama H, Kimura Y, Iwasaki K, Toda K, Kikuchi N, Kumai Y, Nakajima S, Matsumoto Y, Watanabe T, Yanase M, Fukushima S, Tomoyuki F, Kobayashi J, Fukushima N. Left ventricular assist device implantation in an adult male with Danon disease. J Cardiol Cases 2019; 20:106-109. [PMID: 31497177 PMCID: PMC6718825 DOI: 10.1016/j.jccase.2019.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 02/05/2019] [Accepted: 06/10/2019] [Indexed: 11/26/2022] Open
Abstract
Danon disease is an extremely rare inherited disorder characterized by cardiac involvement, myopathy, and intellectual disability. As patients with Danon disease die at an early age, mainly as a result of cardiac involvement, implantation of a left ventricular assist device (LVAD) and/or heart transplantation are essential options. However, various comorbidities associated with Danon disease should be assessed when these patients are being considered as potential heart transplant candidates. We report the case of an adult male patient with dilated-phase hypertrophic cardiomyopathy secondary to Danon disease, who received an LVAD as a bridge to transplantation. <Learning objective: Some patients with Danon disease who underwent heart transplantation have been reported in Japan, but all were female. Male patients with Danon disease have more severe systemic comorbidities than females and heart failure progression is usually too rapid for them to be listed as heart transplant candidates. We present a rare case of an adult male with Danon disease who successfully underwent implantation of a left-ventricular assist device as a bridge to transplantation.>
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Affiliation(s)
- Kensuke Kuroda
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Osamu Seguchi
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Hideo Matama
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Yuki Kimura
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Keiichiro Iwasaki
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Koichi Toda
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Noriko Kikuchi
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Yuto Kumai
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Seiko Nakajima
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Yorihiko Matsumoto
- Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Japan
| | - Takuya Watanabe
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Masanobu Yanase
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
| | - Satsuki Fukushima
- Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Japan
| | - Fujita Tomoyuki
- Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Japan
| | - Junjiro Kobayashi
- Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Japan
| | - Norihide Fukushima
- Department of Transplant Medicine, National Cerebral and Cardiovascular Center, Japan
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Guo S, Zhou L, Wang R, Lv Z, Xu H, Han B, Korantzopoulos P, Hu F, Liu T. Danon disease: Two patients with atrial fibrillation in a single family and review of the literature. Exp Ther Med 2019; 18:1527-1532. [PMID: 31410105 PMCID: PMC6676149 DOI: 10.3892/etm.2019.7777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 05/31/2019] [Indexed: 11/05/2022] Open
Abstract
The present study reports on a family with two members affected by Danon disease but having different phenotypes. The clinical manifestations of Danon disease include cardiomyopathy, skeletal myopathy and different degrees of intellectual disability that varies greatly among patients. The present case study reports on two siblings, an older sister and a younger brother, with Danon disease from an affected pedigree, presenting with distinctly different phenotypes. The sister was diagnosed with dilated cardiomyopathy at the age of 26 years with an unfavorable outcome, while her younger brother presented with hypertrophic cardiomyopathy in a relatively stable state. The two probands shared the same mutation, c.974delTinsAA in exon 8, in the lysosomal-associated membrane protein-2 gene. Of note, the two patients had a pre-excitation pattern in the electrocardiogram on initial presentation and later developed atrial fibrillation (AF), which markedly aggravated heart failure. To the best of our knowledge, AF has not been widely reported in patients with Danon disease. The development of AF may have a prognostic value under these circumstances.
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Affiliation(s)
- Shaohua Guo
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin 300211, P.R. China
| | - Linghuan Zhou
- Department of Cardiology, Shijiazhuang Great Wall Hospital of Integrated Traditional Chinese and Western Medicine, Shijiazhuang, Hebei 050035, P.R. China
| | - Renping Wang
- Department of Cardiology, Shijiazhuang Great Wall Hospital of Integrated Traditional Chinese and Western Medicine, Shijiazhuang, Hebei 050035, P.R. China
| | - Zhixin Lv
- Department of Cardiology, Shijiazhuang Great Wall Hospital of Integrated Traditional Chinese and Western Medicine, Shijiazhuang, Hebei 050035, P.R. China
| | - Hongzun Xu
- Department of Cardiology, Shijiazhuang Great Wall Hospital of Integrated Traditional Chinese and Western Medicine, Shijiazhuang, Hebei 050035, P.R. China
| | - Baoli Han
- Department of Cardiology, Shijiazhuang Great Wall Hospital of Integrated Traditional Chinese and Western Medicine, Shijiazhuang, Hebei 050035, P.R. China
| | | | - Fuli Hu
- Department of Cardiology, Shijiazhuang Great Wall Hospital of Integrated Traditional Chinese and Western Medicine, Shijiazhuang, Hebei 050035, P.R. China
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, The Second Hospital of Tianjin Medical University, Tianjin 300211, P.R. China
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Mulder BA, Hoedemaekers YM, van den Berg MP, van Loon RLE, Wind AM, Jongbloed JDH, Wiesfeld ACP. Three female patients with Danon disease presenting with predominant cardiac phenotype: a case series. EUROPEAN HEART JOURNAL-CASE REPORTS 2019; 3:ytz132. [PMID: 31660500 PMCID: PMC6764575 DOI: 10.1093/ehjcr/ytz132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/04/2018] [Accepted: 07/10/2019] [Indexed: 11/13/2022]
Abstract
Background Danon disease is a rare X-linked multisystemic disorder that has primarily been described in male patients. Case summary We present three female patients with Danon disease with a predominantly cardiac phenotype in whom disease onset and expression was very different from that of male patients. Case 1 was first admitted for acute heart failure and then readmitted a few months later for cardiac shock, necessitating mechanical support, and heart transplantation. Case 2 had complex arrhythmias for which many antiarrhythmic drugs were tried with only limited success. Her disease accelerated after her first pregnancy, and she showed reduced left ventricular function and dilated cardiomyopathy. Case 3 was referred for near syncope and ablated for an accessory pathway; she had extensive left ventricular hypertrophy. In all three cases, a final diagnosis of Danon disease was only made after genetic testing that identified a causal variant in the lysosome-associated membrane protein 2 gene. Discussion Danon disease in female patients is a challenging diagnosis that may not be identified until genetic testing has been performed.
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Affiliation(s)
- Bart A Mulder
- Department of Cardiology, Thoraxcenter, University of Groningen, University Medical Center Groningen, PO Box 30.001, RB Groningen, The Netherlands
| | - Yvonne M Hoedemaekers
- Department of Genetics, Thoraxcenter, University of Groningen, University Medical Center Groningen, PO Box 30.001, RB Groningen, The Netherlands
| | - Maarten P van den Berg
- Department of Cardiology, Thoraxcenter, University of Groningen, University Medical Center Groningen, PO Box 30.001, RB Groningen, The Netherlands
| | - Rosa L E van Loon
- Department of Genetics, University of Utrecht, University Medical Center Utrecht, PO Box 80125, TC Utrecht, The Netherlands
| | - Anna M Wind
- Department of Cardiology, University of Utrecht, Diakonessen Hospital, PO Box 80250, TG Utrecht, The Netherlands
| | - Jan D H Jongbloed
- Department of Genetics, Thoraxcenter, University of Groningen, University Medical Center Groningen, PO Box 30.001, RB Groningen, The Netherlands
| | - Ans C P Wiesfeld
- Department of Cardiology, Thoraxcenter, University of Groningen, University Medical Center Groningen, PO Box 30.001, RB Groningen, The Netherlands
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Oren D, Chau P, Manning M, Kwong J, Kaufman BD, Maeda K, Rosenthal DN, Hollander SA. Heart transplantation in two adolescents with Danon disease. Pediatr Transplant 2019; 23:e13335. [PMID: 30536852 DOI: 10.1111/petr.13335] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/24/2018] [Accepted: 11/08/2018] [Indexed: 12/01/2022]
Abstract
Danon disease (DD) is an X-linked dominant disorder caused by a mutation in the lysosomal-associated membrane protein-2 (LAMP-2) gene coding for the LAMP-2 protein. We report two cases of successful heart transplantation (HT) in adolescent brothers with DD, including one who was bridged to HT for 34 days with a HeartWare left ventricular assist device. In both patients, the post-transplant course was complicated by profound skeletal muscle weakness that resolved with corticosteroid withdrawal. These cases highlight that both HT and ventricular assist device support are feasible in patients with DD. Corticosteroid use may exacerbate skeletal myopathy, and therefore, steroid minimization may be warranted whenever possible.
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Affiliation(s)
- Daniel Oren
- Heart and Vascular Center, Semmelweis University, Budapest, Hungary
| | - Peter Chau
- Department of Pediatrics (Cardiology), Loma Linda Medical Center, Loma Linda, California
| | - Melanie Manning
- Department of Pediatrics (Medical Genetics) and Pathology, Stanford University Medical Center, Stanford University, Stanford, California
| | - Joann Kwong
- Rehabilitation Services, Lucile Packard Children's Hospital, Stanford, California
| | - Beth D Kaufman
- Department of Pediatrics (Cardiology), Stanford University Medical Center, Stanford University, Stanford, California
| | - Katsuhide Maeda
- Department of Cardiothoracic Surgery, Stanford University Medical Center, Stanford, California
| | - David N Rosenthal
- Department of Pediatrics (Cardiology), Stanford University Medical Center, Stanford University, Stanford, California
| | - Seth A Hollander
- Department of Pediatrics (Cardiology), Stanford University Medical Center, Stanford University, Stanford, California
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A Nationwide Survey on Danon Disease in Japan. Int J Mol Sci 2018; 19:ijms19113507. [PMID: 30413001 PMCID: PMC6274850 DOI: 10.3390/ijms19113507] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/04/2018] [Accepted: 11/05/2018] [Indexed: 01/01/2023] Open
Abstract
Danon disease, an X-linked dominant cardioskeletal myopathy, is caused by primary deficiency of lysosome-associated membrane protein-2 (LAMP-2). To clarify the clinicopathological features and management, we performed the first nationwide, questionnaire-based survey on Danon disease in Japan. A total of 39 patients (17 males, 22 females) from 20 families were identified in the analysis. All patients had cardiomyopathy. Of the 21 patients who died, 20 (95%) died of cardiac failure or sudden cardiac arrest. Most patients had hypertrophic cardiomyopathy. Wolf–Parkinson–White syndrome was present at a comparatively high incidence (54% in males, 22% in females). Only one female patient received a heart transplant, which is the most effective therapy. Histopathologically, all male patients showed autophagic vacuoles with sarcolemmal features in muscle. Half of the probands showed de novo mutations. Male patients showed completely absent LAMP-2 expression in muscle. In contrast, female patients showed decreased LAMP-2 expression, which is suggested to reflect LAMP-2 haploinsufficiency due to a heterozygous null mutation. In conclusion, Danon disease is an extremely rare muscular disorder in Japan. Cardiomyopathy is the most significant prognostic factor and the main cause of death. Our findings suggest that the present survey can extend our understanding of the clinical features of this rare disease.
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