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Argente-Escrig H, Vílchez JJ, Frasquet M, Muelas N, Azorín I, Vílchez R, Millet-Sancho E, Pitarch I, Tomás-Vila M, Vázquez-Costa JF, Mas-Estellés F, Marco-Marín C, Espinós C, Serrano-Lorenzo P, Martin MA, Lupo V, Sevilla T. A novel TRMT5 mutation causes a complex inherited neuropathy syndrome: the role of nerve pathology in defining a demyelinating neuropathy. Neuropathol Appl Neurobiol 2022; 48:e12817. [PMID: 35342985 DOI: 10.1111/nan.12817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/09/2022] [Accepted: 03/19/2022] [Indexed: 11/28/2022]
Abstract
AIMS To present data obtained from three patients belonging to three unrelated families with an infantile onset demyelinating neuropathy associated to somatic and neurodevelopmental delay, and to describe the underlying genetic changes. METHODS We performed whole-exome sequencing on genomic DNA from the patients and their parents, and reviewed the clinical, muscle and nerve data, the serial neurophysiological studies, brain, and muscle MRIs, as well as the respiratory chain complex activity in the muscle of the three index patients. Computer modelling was used to characterize the new missense variant detected. RESULTS All three patients had a short stature, delayed motor milestone acquisition, intellectual disability and cerebellar abnormalities associated with a severe demyelinating neuropathy, with distinct morphological features. Despite the proliferation of giant mitochondria, the mitochondrial respiratory chain complex activity in skeletal muscle was normal, except in one patient in whom there was a mild decrease in complex I enzyme activity. All three patients carried the same two compound heterozygous variants of the TRMT5 (tRNA Methyltransferase 5) gene, one known pathogenic frameshift mutation [c.312_315del (p.Ile105Serfs*4)] and a second rare missense change [c.665T>C (p.Ile222Thr)]. TRMT5 is a nuclear-encoded protein involved in the post-transcriptional maturation of mitochondrial tRNA. Computer modelling of the human TRMT5 protein structure suggests that the rare p.Ile222Thr mutation could affect the stability of tRNA binding. CONCLUSIONS Our study expands the phenotype of mitochondrial disorders caused by TRTM5 mutations and defines a new form of recessive demyelinating peripheral neuropathy.
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Affiliation(s)
- Herminia Argente-Escrig
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain
| | - Juan Jesus Vílchez
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain
| | - Marina Frasquet
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain
| | - Nuria Muelas
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain
| | - Inmaculada Azorín
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain
| | - Roger Vílchez
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain
| | - Elvira Millet-Sancho
- Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Department of Clinical Neurophysiology, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Inmaculada Pitarch
- Neuropediatrics Unit, Department of Pediatrics, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Miguel Tomás-Vila
- Neuropediatrics Unit, Department of Pediatrics, Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Juan F Vázquez-Costa
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain.,Department of Medicine, University of Valencia School of Medicine, Valencia, Spain
| | - Fernando Mas-Estellés
- Neurorradiology Section-ASCIRES, Radiology Department. Hospital Universitari i Politècnic La Fe, Valencia, Spain
| | - Clara Marco-Marín
- Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | - Carmen Espinós
- Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain.,Unit of Rare Neurodegenerative Diseases, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Pablo Serrano-Lorenzo
- Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Mitochondrial and Neuromuscular Disorders Research Group, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Miguel A Martin
- Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Mitochondrial and Neuromuscular Disorders Research Group, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Vincenzo Lupo
- Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain.,Unit of Rare Neurodegenerative Diseases, Centro de Investigación Príncipe Felipe (CIPF), Valencia, Spain
| | - Teresa Sevilla
- Neuromuscular & Ataxias Research Group, Instituto de Investigación Sanitaria La Fe, Valencia, Spain.,Neuromuscular Diseases Unit, Department of Neurology, Hospital Universitari i Politècnic La Fe, Valencia, Spain.,Centre for Biomedical Network Research on Rare Diseases-CIBERER, Spain.,Rare Diseases Joint Unit IIS La Fe - CIPF, Valencia, Spain.,Department of Medicine, University of Valencia School of Medicine, Valencia, Spain
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