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Bermejo-Guerrero L, Hernández-Voth A, Serrano-Lorenzo P, Blázquez A, Martin-Jimenez P, Martin MA, Domínguez-González C. Remarkable clinical improvement with oral nucleoside treatment in a patient with adult-onset TK2 deficiency: A case report. Mitochondrion 2024; 76:101879. [PMID: 38599303 DOI: 10.1016/j.mito.2024.101879] [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: 01/10/2024] [Revised: 03/09/2024] [Accepted: 04/07/2024] [Indexed: 04/12/2024]
Abstract
OBJECTIVES Thymidine kinase 2 deficiency (TK2d) is a rare autosomal recessive mitochondrial disorder. It manifests as a continuous clinical spectrum, from fatal infantile mitochondrial DNA depletion syndromes to adult-onset mitochondrial myopathies characterized by ophthalmoplegia-plus phenotypes with early respiratory involvement. Treatment with pyrimidine nucleosides has recently shown striking effects on survival and motor outcomes in the more severe infantile-onset clinical forms. We present the response to treatment in a patient with adult-onset TK2d. METHODS An adult with ptosis, ophthalmoplegia, facial, neck, and proximal muscle weakness, non-invasive nocturnal mechanical ventilation, and dysphagia due to biallelic pathogenic variants in TK2 received treatment with 260 mg/kg/day of deoxycytidine (dC) and deoxythymidine (dT) under a Compassionate Use Program. Prospective motor and respiratory assessments are presented. RESULTS After 27 months of follow-up, the North Star Ambulatory Assessment improved by 11 points, he walked 195 m more in the 6 Minute-Walking-Test, ran 10 s faster in the 100-meter time velocity test, and the Forced Vital Capacity stabilized. Growth Differentiation Factor-15 (GDF15) levels, a biomarker of respiratory chain dysfunction, normalized. The only reported side effect was dose-dependent diarrhea. DISCUSSION Treatment with dC and dT can significantly improve motor performance and stabilize respiratory function safely in patients with adult-onset TK2d.
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Affiliation(s)
- Laura Bermejo-Guerrero
- Neurology Department, Neuromuscular Disorders Unit, Hospital 12 de Octubre, Madrid 28041, Spain
| | - Ana Hernández-Voth
- Pulmonology Department, Mechanical Ventilation and Neuromuscular Disorders Unit, Hospital 12 de Octubre, Madrid 28041, Spain
| | - Pablo Serrano-Lorenzo
- Spanish Network for Biomedical Research in Rare Diseases (CIBERER), Madrid 28029, Spain
| | - Alberto Blázquez
- Spanish Network for Biomedical Research in Rare Diseases (CIBERER), Madrid 28029, Spain; Mitochondrial and Neuromuscular Research Group '12 de Octubre', Hospital Research Institute (imas12), Madrid 28041, Spain
| | - Paloma Martin-Jimenez
- Neurology Department, Neuromuscular Disorders Unit, Hospital 12 de Octubre, Madrid 28041, Spain
| | - Miguel A Martin
- Spanish Network for Biomedical Research in Rare Diseases (CIBERER), Madrid 28029, Spain; Mitochondrial and Neuromuscular Research Group '12 de Octubre', Hospital Research Institute (imas12), Madrid 28041, Spain; Genetics Department, Hospital Universitario, 12 de Octubre, Madrid 28041, Spain
| | - Cristina Domínguez-González
- Neurology Department, Neuromuscular Disorders Unit, Hospital 12 de Octubre, Madrid 28041, Spain; Spanish Network for Biomedical Research in Rare Diseases (CIBERER), Madrid 28029, Spain; Mitochondrial and Neuromuscular Research Group '12 de Octubre', Hospital Research Institute (imas12), Madrid 28041, Spain.
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Lin Y, Yang B, Huang Y, Zhang Y, Jiang Y, Ma L, Shen YQ. Mitochondrial DNA-targeted therapy: A novel approach to combat cancer. CELL INSIGHT 2023; 2:100113. [PMID: 37554301 PMCID: PMC10404627 DOI: 10.1016/j.cellin.2023.100113] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 08/10/2023]
Abstract
Mitochondrial DNA (mtDNA) encodes proteins and RNAs that are essential for mitochondrial function and cellular homeostasis, and participates in important processes of cellular bioenergetics and metabolism. Alterations in mtDNA are associated with various diseases, especially cancers, and are considered as biomarkers for some types of tumors. Moreover, mtDNA alterations have been found to affect the proliferation, progression and metastasis of cancer cells, as well as their interactions with the immune system and the tumor microenvironment (TME). The important role of mtDNA in cancer development makes it a significant target for cancer treatment. In recent years, many novel therapeutic methods targeting mtDNA have emerged. In this study, we first discussed how cancerogenesis is triggered by mtDNA mutations, including alterations in gene copy number, aberrant gene expression and epigenetic modifications. Then, we described in detail the mechanisms underlying the interactions between mtDNA and the extramitochondrial environment, which are crucial for understanding the efficacy and safety of mtDNA-targeted therapy. Next, we provided a comprehensive overview of the recent progress in cancer therapy strategies that target mtDNA. We classified them into two categories based on their mechanisms of action: indirect and direct targeting strategies. Indirect targeting strategies aimed to induce mtDNA damage and dysfunction by modulating pathways that are involved in mtDNA stability and integrity, while direct targeting strategies utilized molecules that can selectively bind to or cleave mtDNA to achieve the therapeutic efficacy. This study highlights the importance of mtDNA-targeted therapy in cancer treatment, and will provide insights for future research and development of targeted drugs and therapeutic strategies.
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Affiliation(s)
- Yumeng Lin
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Bowen Yang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Yibo Huang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - You Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Yu Jiang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Longyun Ma
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Ying-Qiang Shen
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Research Unit of Oral Carcinogenesis and Management, Chinese Academy of Medical Sciences, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, PR China
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Metrics of progression and prognosis in untreated adults with thymidine kinase 2 deficiency: An observational study. Neuromuscul Disord 2022; 32:728-735. [PMID: 35907766 DOI: 10.1016/j.nmd.2022.07.399] [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: 01/20/2022] [Revised: 06/23/2022] [Accepted: 07/13/2022] [Indexed: 11/21/2022]
Abstract
This historical cohort study evaluated clinical characteristics of progression and prognosis in adults with thymidine kinase 2 deficiency (TK2d). Records were available for 17 untreated adults with TK2d (mean age of onset, 32 years), including longitudinal data from 6 patients (mean follow-up duration, 26.5 months). Pearson's correlation assessed associations between standard motor and respiratory assessments, clinical characteristics, and laboratory values. Longitudinal data were assessed by linear regression mixed models. Respiratory involvement progressed at an annual rate of 8.16% decrement in forced vital capacity (FVC). Most patients under noninvasive ventilation (NIV) remained ambulant (12/14, 86%), reduced FVC was not associated with concomitant decline in 6-minute walk test (6MWT), and 6MWT results were not correlated with FVC. Disease severity, assessed by age at NIV onset, correlated most strongly at diagnosis with: creatinine levels (r = 0.8036; P = 0.0009), followed by FVC (r = 0.7265; P = 0.0033), mtDNA levels in muscle (r = 0.7933; P = 0.0188), and age at disease onset (r = 0.7128; P = 0.0042). This population of adults with TK2d demonstrates rapid deterioration of respiratory muscles, which progresses independently of motor impairment. The results support FVC at diagnosis, mtDNA levels in muscle, and age at disease onset as prognostic indicators. Creatinine levels may also be potentially prognostic, as previously reported in other neuromuscular disorders.
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Domínguez-González C, Madruga-Garrido M, Hirano M, Martí I, Martín MA, Munell F, Nascimento A, Olivé M, Quan J, Sardina MD, Martí R, Paradas C. Collaborative model for diagnosis and treatment of very rare diseases: experience in Spain with thymidine kinase 2 deficiency. Orphanet J Rare Dis 2021; 16:407. [PMID: 34600563 PMCID: PMC8487573 DOI: 10.1186/s13023-021-02030-w] [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: 06/17/2021] [Accepted: 09/18/2021] [Indexed: 11/22/2022] Open
Abstract
Background Mitochondrial diseases are difficult to diagnose and treat. Recent advances in genetic diagnostics and more effective treatment options can improve patient diagnosis and prognosis, but patients with mitochondrial disease typically experience delays in diagnosis and treatment. Here, we describe a unique collaborative practice model among physicians and scientists in Spain focused on identifying TK2 deficiency (TK2d), an ultra-rare mitochondrial DNA depletion and deletions syndrome.
Main Body This collaboration spans research and clinical care, including laboratory scientists, adult and pediatric neuromuscular clinicians, geneticists, and pathologists, and has resulted in diagnosis and consolidation of care for patients with TK2d. The incidence of TK2d is not known; however, the first clinical cases of TK2d were reported in 2001, and only ~ 107 unique cases had been reported as of 2018. This unique collaboration in Spain has led to the diagnosis of more than 30 patients with genetically confirmed TK2d across different regions of the country. Research affiliate centers have led investigative treatment with nucleosides based on understanding of TK2d clinical manifestations and disease mechanisms, which resulted in successful treatment of a TK2d mouse model with nucleotide therapy in 2010. Only 1 year later, this collaboration enabled rapid adoption of treatment with pyrimidine nucleotides (and later, nucleosides) under compassionate use. Success in TK2d diagnosis and treatment in Spain is attributable to two important factors: Spain’s fully public national healthcare system, and the designation in 2015 of major National Reference Centers for Neuromuscular Disorders (CSURs). CSUR networking and dissemination facilitated development of a collaborative care network for TK2d disease, wherein participants share information and protocols to request approval from the Ministry of Health to initiate nucleoside therapy. Data have recently been collected in a retrospective study conducted under a Good Clinical Practice–compliant protocol to support development of a new therapeutic approach for TK2d, a progressive disease with no approved therapies. Conclusions The Spanish experience in diagnosis and treatment of TK2d is a model for the diagnosis and development of new treatments for very rare diseases within an existing healthcare system.
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Affiliation(s)
- Cristina Domínguez-González
- Neuromuscular Disorders Unit, Neurology Department, Hospital 12 de Octubre, Madrid, Spain.,Instituto de Investigación imas12, Hospital 12 de Octubre, Madrid, Spain.,Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Michio Hirano
- Neurology Department, H. Houston Merritt Center, Columbia University Irving Medical Center, New York, NY, USA
| | - Itxaso Martí
- Pediatric Department, Donostia University Hospital, Biodonostia Health Research Institute, University of the Basque Country, San Sebastián, Spain
| | - Miguel A Martín
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Mitochondrial Diseases Laboratory, Department of Biochemistry, Research Institute Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Francina Munell
- Pediatric Department, Vall d'Hebron Hospital, Barcelona, Spain
| | - Andrés Nascimento
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Pediatric Department, Vall d'Hebron Hospital, Barcelona, Spain.,Neuromuscular Unit, Neurology Department, Sant Joan de Déu Research Institute, Sant Joan de Déu Hospital, Barcelona, Spain
| | - Montse Olivé
- Neuromuscular Disorders Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau/Center for Biomedical Network Research On Rare Diseases (CIBERER), Barcelona, Spain
| | | | - M Dolores Sardina
- Pediatric Neurology Department, Badajoz Hospital Complex, Badajoz, Spain
| | - Ramon Martí
- Center for Biomedical Network Research On Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain.,Research Group On Neuromuscular and Mitochondrial Diseases, Vall d'Hebron Research Institute, Autonomous University of Barcelona, Barcelona, Spain
| | - Carmen Paradas
- Neurology Department, Neuromuscular Disorders Unit, Instituto de Biomedicina de Sevilla, Hospital U. Virgen del Rocío, CSIC, Universidad de Sevilla, Avd. Manuel Siurot s/n, 41013, Sevilla, Spain. .,Center for Biomedical Network Research On Neurodegenerative Disorders (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.
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