title: [A case of mitochondrial cytopathy (MERFF) without ragged red fibers at the onset].
abstract: We report a case of a mitochondrial cytopathy (MERRF) with a late diagnosis because of the absence of Ragged-Red Fibers (RRF) in the first muscular biopsy performed in childhood. Eight years after the onset of the disease the familial history and the clinical manifestations were very suggestive of a mitochondrial cytopathy and a second biopsy was performed confirming the diagnosis of MERRF. The authors discuss several hypotheses to explain the negativity of the first muscular biopsy. The absence of ragged-red fibers does not exclude the diagnosis of a mitochondrial cytopathy and other investigations are justified such as the biochemical study of the respiratory chain and the molecular analysis of mitochondrial DNA.
authors.affiliation: Fédération de Neurologie des Prs. Agid et Lyon-Caen, Paris, Cedex, France.
authors.forename: L
authors.initials: L
authors.lastname: Gignoux
authors.forename: T
authors.initials: T
authors.lastname: Maisonobe
authors.forename: P
authors.initials: P
authors.lastname: Laforet
authors.forename: A
authors.initials: A
authors.lastname: Lombès
authors.forename: O
authors.initials: O
authors.lastname: Lyon-Caen
authors.forename: B
authors.initials: B
authors.lastname: Fontaine
mesh_terms: D000328:Adult; D001706:Biopsy; D003937:Diagnosis, Differential; D003576:Electron Transport Complex IV / Q000032:analysis; D005500:Follow-Up Studies; D006801:Humans; D017243:MERRF Syndrome / Q000473:pathology*; D008297:Male; D018656:Muscle Fibers, Fast-Twitch / Q000473:pathology*; D018482:Muscle, Skeletal / Q000473:pathology*; D013385:Succinate Dehydrogenase / Q000032:analysis
chemical_list: D013385:Succinate Dehydrogenase; D003576:Electron Transport Complex IV