title: Mitochondrial myopathy associated with a novel 5522G>A mutation in the mitochondrial tRNA(Trp) gene.
abstract: We report a novel pathogenic mutation of the mitochondrial transfer RNA (tRNA) gene for tryptophan in a patient with isolated myopathy and persistently elevated creatine kinase. Muscle studies revealed ragged red fibres and decreased activity of respiratory chain complex I and cytochrome c oxidase (COX). Sequencing of the 22 mitochondrial tRNA genes revealed a mutation m.5522G>A, which alters a conserved base pairing in the D-stem of the tRNA for tryptophan. The mutation was heteroplasmic with a mutational load between 88 and 99% in COX-negative fibres. This case contributes to the genetic heterogeneity of mitochondrial diseases caused by mutations in mitochondrial tRNA genes.
authors.affiliation: Department of Paediatrics, University Hospital Centre Zagreb, Zagreb, Croatia. ibaric@kbc-zagreb.hr
authors.forename: Ivo
authors.initials: I
authors.lastname: Barić
authors.forename: Ksenija
authors.initials: K
authors.lastname: Fumić
authors.forename: Danijela
authors.initials: D
authors.lastname: Petković Ramadža
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Sperl
authors.forename: Franz A
authors.initials: FA
authors.lastname: Zimmermann
authors.forename: Diana
authors.initials: D
authors.lastname: Muačević-Katanec
authors.forename: Zoran
authors.initials: Z
authors.lastname: Mitrović
authors.forename: Leo
authors.initials: L
authors.lastname: Pažanin
authors.forename: Ljerka
authors.initials: L
authors.lastname: Cvitanović Šojat
authors.forename: Tihomir
authors.initials: T
authors.lastname: Kekez
authors.forename: Zeljko
authors.initials: Z
authors.lastname: Reiner
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Mayr
mesh_terms: D000293:Adolescent; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics; D042967:Electron Transport Complex I / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D017240:Mitochondrial Myopathies / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D018657:Muscle Fibers, Slow-Twitch / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D017354:Point Mutation; D012364:RNA, Transfer, Trp / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004272:DNA, Mitochondrial; D012364:RNA, Transfer, Trp; D003576:Electron Transport Complex IV; D042967:Electron Transport Complex I