Inhibition of mitochondrial translation in fibroblasts from a patient expressing the KARS p.(Pro228Leu) variant and presenting with sensorineural deafness, developmental delay, and lactic acidosis.

Autor: Ruzzenente B; INSERM UMR1163, Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, Paris, France., Assouline Z; Departments of Pediatrics, Neurology and Genetics, Hôpital Necker-Enfants-Malades, Paris, France., Barcia G; Departments of Pediatrics, Neurology and Genetics, Hôpital Necker-Enfants-Malades, Paris, France., Rio M; Departments of Pediatrics, Neurology and Genetics, Hôpital Necker-Enfants-Malades, Paris, France., Boddaert N; Department of pediatric radiology, INSERM 1000 and INSERM UMR1136, Hôpital Necker-Enfants-Malades AP-HP, Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, Paris, France., Munnich A; INSERM UMR1163, Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, Paris, France.; Departments of Pediatrics, Neurology and Genetics, Hôpital Necker-Enfants-Malades, Paris, France., Rötig A; INSERM UMR1163, Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, Paris, France., Metodiev MD; INSERM UMR1163, Université Paris Descartes - Sorbonne Paris Cité, Institut Imagine, Paris, France.
Jazyk: angličtina
Zdroj: Human mutation [Hum Mutat] 2018 Dec; Vol. 39 (12), pp. 2047-2059. Date of Electronic Publication: 2018 Oct 03.
DOI: 10.1002/humu.23657
Abstrakt: Aminoacyl-tRNA synthetases are ubiquitous enzymes, which universally charge tRNAs with their cognate amino acids for use in cytosolic or organellar translation. In humans, mutations in mitochondrial tRNA synthetases have been linked to different tissue-specific pathologies. Mutations in the KARS gene, which encodes both the cytosolic and mitochondrial isoform of lysyl-tRNA synthetase, cause predominantly neurological diseases that often involve deafness, but have also been linked to cardiomyopathy, developmental delay, and lactic acidosis. Using whole exome sequencing, we identified two compound heterozygous mutations, NM_001130089.1:c.683C>T p.(Pro228Leu) and NM_001130089.1:c.1438del p.(Leu480TrpfsX3), in a patient presenting with sensorineural deafness, developmental delay, hypotonia, and lactic acidosis. Nonsense-mediated mRNA decay eliminated the truncated mRNA transcript, rendering the patient hemizygous for the missense mutation. The c.683C>T mutation was previously described, but its pathogenicity remained unexamined. Molecular characterization of patient fibroblasts revealed a multiple oxidative phosphorylation deficiency due to impaired mitochondrial translation, but no evidence of inhibition of cytosolic translation. Reintroduction of wild-type mitochondrial KARS, but not the cytosolic isoform, rescued this phenotype confirming the disease-causing nature of p.(Pro228Leu) exchange and demonstrating the mitochondrial etiology of the disease. We propose that mitochondrial translation deficiency is the probable disease culprit in this and possibly other patients with mutations in KARS.
(© 2018 Wiley Periodicals, Inc.)
Databáze: MEDLINE
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