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Messina M, Vaz FM, Rahman S. Mitochondrial membrane synthesis, remodelling and cellular trafficking. J Inherit Metab Dis 2024. [PMID: 38872485 DOI: 10.1002/jimd.12766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 05/14/2024] [Accepted: 05/21/2024] [Indexed: 06/15/2024]
Abstract
Mitochondria are dynamic cellular organelles with complex roles in metabolism and signalling. Primary mitochondrial disorders are a group of approximately 400 monogenic disorders arising from pathogenic genetic variants impacting mitochondrial structure, ultrastructure and/or function. Amongst these disorders, defects of complex lipid biosynthesis, especially of the unique mitochondrial membrane lipid cardiolipin, and membrane biology are an emerging group characterised by clinical heterogeneity, but with recurrent features including cardiomyopathy, encephalopathy, neurodegeneration, neuropathy and 3-methylglutaconic aciduria. This review discusses lipid synthesis in the mitochondrial membrane, the mitochondrial contact site and cristae organising system (MICOS), mitochondrial dynamics and trafficking, and the disorders associated with defects of each of these processes. We highlight overlapping functions of proteins involved in lipid biosynthesis and protein import into the mitochondria, pointing to an overarching coordination and synchronisation of mitochondrial functions. This review also focuses on membrane interactions between mitochondria and other organelles, namely the endoplasmic reticulum, peroxisomes, lysosomes and lipid droplets. We signpost disorders of these membrane interactions that may explain the observation of secondary mitochondrial dysfunction in heterogeneous pathological processes. Disruption of these organellar interactions ultimately impairs cellular homeostasis and organismal health, highlighting the central role of mitochondria in human health and disease.
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Affiliation(s)
- Martina Messina
- Mitochondrial Research Group, Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Frédéric M Vaz
- Department of Laboratory Medicine and Pediatrics, Laboratory Genetic Metabolic Diseases, Emma Children's Hospital, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Inborn Errors of Metabolism, Amsterdam, The Netherlands
| | - Shamima Rahman
- Mitochondrial Research Group, Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, London, UK
- Metabolic Unit, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
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A novel AGK splicing mutation in a patient with Sengers syndrome and left ventricular non-compaction cardiomyopathy. Pediatr Res 2023:10.1038/s41390-023-02515-3. [PMID: 36759750 DOI: 10.1038/s41390-023-02515-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/16/2022] [Accepted: 01/21/2023] [Indexed: 02/11/2023]
Abstract
BACKGROUND Sengers syndrome characterized by hypertrophic cardiomyopathy is an extremely rare genetic disorder. Sengers syndrome associated with left ventricular non-compaction (LVNC) has not been described. METHODS Genetic testing was used to identify candidate AGK variants in the proband. The predicted molecular structures were constructed by protein modeling. Exon skipping caused by the identified splicing mutations was verified by in silico analyses and in vitro assays. The genotypic and phenotypic features of patients with AGK splicing mutations were extracted by a systematic review. RESULTS The proband was characterized by Sengers syndrome and LVNC and caused by a novel compound heterozygous AGK splicing mutation. This compound mutation simultaneously perturbed the protein sequences and spatial conformation of the acylglycerol kinase protein. In silico and in vitro analyses demonstrated skipping of exons 7 and 8 and premature truncation as a result of exon 8 skipping. The systematic review indicated that patients with an AGK splicing mutation may have milder phenotypes of Sengers syndrome. CONCLUSIONS The genotypic and phenotypic spectrums of Sengers syndrome have been expanded, which will provide essential information for genetic counseling. The molecular mechanism in AGK mutations can offer insights into the potential targets for treatment. IMPACT First description of a child with Sengers syndrome and left ventricular non-compaction cardiomyopathy. A novel pathogenic compound heterozygous splicing mutation in AGK for Sengers syndrome was identified. The identified mutations led to exons skipping by in silico analyses and in vitro assays.
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Panicucci C, Schiaffino MC, Nesti C, Derchi M, Trocchio G, Severino M, Stagnaro N, Priolo E, Zara F, Santorelli FM, Bruno C. Long term follow-up in two siblings with Sengers syndrome: Case report. Ital J Pediatr 2022; 48:180. [PMID: 36253788 PMCID: PMC9575244 DOI: 10.1186/s13052-022-01370-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/28/2022] [Accepted: 09/13/2022] [Indexed: 11/24/2022] Open
Abstract
Background Sengers syndrome is characterized by congenital cataract, hypertrophic cardiomyopathy, mitochondrial myopathy, and lactic acidosis associated with mutations in AGK gene. Clinical course ranges from a severe fatal neonatal form, to a more benign form allowing survival into adulthood, to an isolated form of congenital cataract. Thus far few reported cases have survived the second decade at their latest examination, and no natural history data are available for the disease. Case presentation Here we provide a 20-year follow-up in two siblings with a benign form of Sengers syndrome, expanding the phenotypical spectrum of the disease by reporting a condition of ovarian agenesis. Conclusion To our knowledge, this report provides the first longitudinal data of Sengers syndrome patients. Supplementary information The online version contains supplementary material available at 10.1186/s13052-022-01370-y.
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Affiliation(s)
- Chiara Panicucci
- Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Via G. Gaslini, 5, I-16147, Genova, Italy
| | | | - Claudia Nesti
- Molecular Medicine, IRCCS Stella Maris Foundation, Pisa, Italy
| | - Maria Derchi
- Cardiology Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | | | | | - Nicola Stagnaro
- Radiology Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Enrico Priolo
- Ophthalmology Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Federico Zara
- Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genova, Italy.,Department of Neurology, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy
| | | | - Claudio Bruno
- Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Via G. Gaslini, 5, I-16147, Genova, Italy. .,Department of Neurology, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genova, Italy.
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Wang H, Han Y, Li S, Chen Y, Chen Y, Wang J, Zhang Y, Zhang Y, Wang J, Xia Y, Yuan J. Mitochondrial DNA Depletion Syndrome and Its Associated Cardiac Disease. Front Cardiovasc Med 2022; 8:808115. [PMID: 35237671 PMCID: PMC8882844 DOI: 10.3389/fcvm.2021.808115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/23/2021] [Indexed: 12/06/2022] Open
Abstract
Mitochondria is a ubiquitous, energy-supplying (ATP-based) organelle found in nearly all eukaryotes. It acts as a “power plant” by producing ATP through oxidative phosphorylation, providing energy for the cell. The bioenergetic functions of mitochondria are regulated by nuclear genes (nDNA). Mitochondrial DNA (mtDNA) and respiratory enzymes lose normal structure and function when nuclear genes encoding the related mitochondrial factors are impaired, resulting in deficiency in energy production. Massive generation of reactive oxygen species and calcium overload are common causes of mitochondrial diseases. The mitochondrial depletion syndrome (MDS) is associated with the mutations of mitochondrial genes in the nucleus. It is a heterogeneous group of progressive disorders characterized by the low mtDNA copy number. TK2, FBXL4, TYPM, and AGK are genes known to be related to MDS. More recent studies identified new mutation loci associated with this disease. Herein, we first summarize the structure and function of mitochondria, and then discuss the characteristics of various types of MDS and its association with cardiac diseases.
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Affiliation(s)
- Haiying Wang
- Department of Physiology, Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yijun Han
- Clinical Medical College, Jining Medical University, Jining, China
| | - Shenwei Li
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yunan Chen
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yafen Chen
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Jing Wang
- Dongying Fifth People's Hospital, Dongying, China
| | - Yuqing Zhang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yawen Zhang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Jingsuo Wang
- Institute of Basic Medical College, Jining Medical University, Jining, China
| | - Yong Xia
- Key Laboratory of Precision Oncology of Shandong Higher Education, Institute of Precision Medicine, Jining Medical University, Jining, China
- Yong Xia
| | - Jinxiang Yuan
- The Collaborative Innovation Center, Jining Medical University, Jining, China
- *Correspondence: Jinxiang Yuan
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Fnon NF, Hassan HH, Ali HM, Sobh ZK. Sengers syndrome: a rare case of cardiomyopathy combined with congenital cataracts in an infant: post-mortem case report. Cardiovasc Pathol 2021; 54:107371. [PMID: 34274418 DOI: 10.1016/j.carpath.2021.107371] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 02/01/2023] Open
Abstract
Sengers syndrome is a rare autosomal recessive disorder caused by a mutation in the Acylglycerol Kinase (AGK) gene with subsequent mitochondrial dysfunction. It is a combination of cardiomyopathy, skeletal myopathy, congenital bilateral cataracts, and lactic acidosis following exertion. The current study describes an extremely rare case of Sengers syndrome that is diagnosed during post-mortem examination. A four-month-old female child underwent sudden cardiac arrest immediately following the induction of general anesthesia for lens extraction surgery. This infant was the first child born to healthy, non-consanguineous, Egyptian parents. There were unremarkable medical problems either during pregnancy or during delivery. This infant was born at term with a normal APGAR score and weight. She had congenital bilateral cataracts since birth, easily-fatigued, and delayed milestones for her age. A post-mortem examination revealed a hypertrophied heart that weighed 96.6 grams with left ventricular hypertrophy. The left ventricle free wall thickness was 1cm, and an interventricular septum thickness of 1.3 cm. Histopathologically, the myocardium showed myocytes disarray. Also, the myocytes were hypertrophied, and vacuolated. The Gömöri trichrome stain revealed vacuolated cardiomyocytes surrounded by collagenous connective tissue, and the Periodic Acid Schiff (PAS) stain excluded that these vacuolations were related to glycogen storage disease. Focal lymphocytic infiltrations were observed within the myocardium. Thus, Sengers syndrome should be taken into consideration as a possible diagnosis whenever a congenital cataract is present for clinical and medicolegal cases.
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Affiliation(s)
- Nora Fawzy Fnon
- Forensic Pathology Department, Forensic Medicine Authority, Ministry of Justice, Cairo, Egypt
| | - Hanan Hosney Hassan
- Forensic Pathology Department, Forensic Medicine Authority, Ministry of Justice, Cairo, Egypt
| | - Hazem Mahmoud Ali
- Forensic Pathology Department, Forensic Medicine Authority, Ministry of Justice, Cairo, Egypt
| | - Zahraa Khalifa Sobh
- Forensic Medicine and Clinical Toxicology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt..
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