title: A novel de novo mutation of the mitochondrial tRNAlys gene mt.8340G>a associated with pure myopathy.
abstract: Most patients with mutations in the tRNA(lys) gene (MTTK) present with symptoms from the central nervous system (CNS). We describe a 41-year-old woman with pure myopathy associated with a novel de novo mtDNA mutation, mt.8340G>A, which was heteroplasmic in muscle (53%), blood, urine and mouth epithelial cells (<7%). No other family members, including her mother, carried the mutation. She presented with exercise intolerance from age 9, and since age 20 she experienced ptosis and reduced ocular motility. A muscle biopsy revealed ragged red fibres (10%), no COX negative fibres, and many fibres with central nuclei (30%), indicating ongoing damage and repair. The present case expands the mutational and phenotypic spectrum of diseases associated with mutations in MTTK.
authors.affiliation: Neuromuscular Research Unit, Section 3342, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark. Electronic address: tina@dysgaard.dk.
authors.forename: Tina Dysgaard
authors.initials: TD
authors.lastname: Jeppesen
authors.affiliation: Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Duno
authors.affiliation: Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark.
authors.forename: Lotte
authors.initials: L
authors.lastname: Risom
authors.affiliation: Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark.
authors.forename: Flemming
authors.initials: F
authors.lastname: Wibrand
authors.affiliation: Neuromuscular Research Unit, Section 3342, Rigshospitalet, University of Copenhagen, Denmark.
authors.forename: Jabin
authors.initials: J
authors.lastname: Rafiq
authors.affiliation: Neuromuscular Research Unit, Section 3342, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Krag
authors.affiliation: Department of Neurology, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark.
authors.forename: Johannes
authors.initials: J
authors.lastname: Jakobsen
authors.affiliation: Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark.
authors.forename: Henning
authors.initials: H
authors.lastname: Andersen
authors.affiliation: Neuromuscular Research Unit, Section 3342, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Rigshospitalet, University of Copenhagen, Denmark; Department of Neurology, Aarhus Hospital, University of Aarhus, Denmark.
authors.forename: John
authors.initials: J
authors.lastname: Vissing
mesh_terms: D000328:Adult; D001483:Base Sequence; D059018:DNA Contamination; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology; D009135:Muscular Diseases / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D010375:Pedigree; D017354:Point Mutation; D012357:RNA, Transfer, Lys / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D012357:RNA, Transfer, Lys
keywords: MTTK gene; Mitochondrial DNA; Novel mutation; tRNA(lys)