title: Unusual presentations of patients with the mitochondrial MERRF mutation A8344G.
abstract: MERRF is typically characterized by myoclonus, generalized seizures and ragged-red fibers in muscular biopsy. We report a family (harbouring the A8344G mutation) with a late onset of the disease and an uncommon clinical manifestation, including episodes of reversible respiratory failure, the presence of ophthalmoplegia, and the absence of seizures and myoclonus in most subjects. We conducted histochemical, biochemical and molecular genetic studies. Mutation analysis revealed that the level of mutated mitochondrial DNA (mtDNA) was above 80% in the skeletal muscle of all siblings. Nevertheless, one severely affected individual did neither present cytochrome c oxidase-negative fibers nor ragged-red fibers in the skeletal muscle biopsy. These data extend the phenotypic range associated with the MERRF syndrome. We suggest that the analysis of mtDNA could be of importance in many cases of unclear multisystem disorders in later life.
authors.affiliation: Klinik für Neurologie, Otto-von-Guericke Universität, D-39120 Magdeburg, Germany. falk.wiedemann@medizin.uni-magdeburg.de
authors.forename: Falk R
authors.initials: FR
authors.lastname: Wiedemann
authors.forename: Claudius
authors.initials: C
authors.lastname: Bartels
authors.forename: Elmar
authors.initials: E
authors.lastname: Kirches
authors.forename: Christian
authors.initials: C
authors.lastname: Mawrin
authors.forename: Claus-W
authors.initials: CW
authors.lastname: Wallesch
mesh_terms: D000368:Aged; D004272:DNA, Mitochondrial / Q000235:genetics; D004569:Electroencephalography; D004576:Electromyography; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D017243:MERRF Syndrome / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology / Q000473:pathology; D018482:Muscle, Skeletal / Q000473:pathology; D009154:Mutation / Q000502:physiology; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D004272:DNA, Mitochondrial; D011451:Prostaglandin-Endoperoxide Synthases; D013385:Succinate Dehydrogenase