A1 Refereed original research article in a scientific journal
Case report: a novel frameshift mutation in the mitochondrial cytochrome c oxidase II gene causing mitochondrial disorder
Authors: Laura Kytövuori, Mikko Kärppä, Hannu Tuominen, Johanna Uusimaa, Markku Saari, Reetta Hinttala, Kari Majamaa
Publisher: BIOMED CENTRAL LTD
Publication year: 2017
Journal: BMC Neurology
Journal name in source: BMC NEUROLOGY
Journal acronym: BMC NEUROL
Article number: 96
Volume: 17
Number of pages: 5
ISSN: 1471-2377
DOI: https://doi.org/10.1186/s12883-017-0883-5
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/25303173
Background: Mitochondrial cytochrome c oxidase 2, MT-CO2, encodes one of the three subunits, which form the catalytic core of cytochrome c oxidase (COX), complex IV. Mutations in MT-CO2 are rare and the associated phenotypes are variable including nonsyndromic and syndromic forms of mitochondrial diseases.Case presentation: We describe a 30-year-old man with cognitive decline, epilepsy, psychosis, exercise intolerance, sensorineural hearing impairment, retinitis pigmentosa, cataract and lactic acidosis. COX-deficient fibers and ragged red fibers were abundant in the muscle. Sequencing of mitochondrial DNA (mtDNA) revealed a novel frameshift mutation m.8156delG that was predicted to cause altered C-terminal amino acid sequence and to lead to truncation of the COX subunit 2. The deletion was heteroplasmic being present in 26% of the mtDNA in blood, 33% in buccal mucosa and 95% in muscle. Deletion heteroplasmy correlated with COX-deficiency in muscle histochemistry. The mother and the siblings of the proband did not harbor the deletion.Conclusions: The clinical features and muscle histology of the proband suggested a mitochondrial disorder. The m.8156delG deletion is a new addition to the short list of pathogenic mutations in the mtDNA-encoded subunits of COX. This case illustrates the importance of mtDNA sequence analysis in patients with an evident mitochondrial disorder.
Downloadable publication This is an electronic reprint of the original article. |  |
