title: Mitochondrial myopathy in a child with a muscle-restricted mutation in the mitochondrial transfer RNAAsn gene.
abstract: We report an 11-year-old boy with exercise-related myopathy, and a novel mutation m.5669G>A in the mitochondrial tRNA Asparagine gene (mt-tRNA(Asn), MTTN). Muscle biopsy studies showed COX-negative, SDH-positive fibers at histochemistry and biochemical defects of oxidative metabolism. The m.5669G>A mutation was present only in patient's muscle resulting in the first muscle-specific MTTN mutation. Mt-tRNA(Asn) steady-state levels and in silico predictions supported the pathogenicity of this mutation. A mitochondrial myopathy should be considered in the differential diagnosis of exercise intolerance in children.
authors: Unit of Muscular and Neurodegenerative Disease, IRCCS G. Gaslini Institute, Genova, Italy. claudiobruno@ospedale-gaslini.ge.it
authors: Claudio
authors: C
authors: Bruno
authors: Denise
authors: D
authors: Cassandrini
authors: Fabiana
authors: F
authors: Fattori
authors: Marina
authors: M
authors: Pedemonte
authors: Chiara
authors: C
authors: Fiorillo
authors: Giorgia
authors: G
authors: Brigati
authors: Giacomo
authors: G
authors: Brisca
authors: Carlo
authors: C
authors: Minetti
authors: Filippo M
authors: FM
authors: Santorelli
mesh_terms: D001483:Base Sequence; D002648:Child; D004272:DNA, Mitochondrial / Q000235:genetics*; D017079:Exercise Tolerance / Q000235:genetics; D006801:Humans; D008297:Male; D008931:Mitochondria, Muscle / Q000235:genetics*; D017240:Mitochondrial Myopathies / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D008969:Molecular Sequence Data; D018908:Muscle Weakness / Q000235:genetics / Q000473:pathology; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry / Q000235:genetics*; D000077278:RNA, Mitochondrial; D012348:RNA, Transfer, Asn / Q000737:chemistry / Q000235:genetics*
chemical_list: D004272:DNA, Mitochondrial; D000077278:RNA, Mitochondrial; D012348:RNA, Transfer, Asn; D012313:RNA