Unusual presentations of patients with the mitochondrial MERRF mutation A8344G

• Published in: Clinical neurology and neurosurgery 2008-09, Vol.110 (8), p.859-863
• Main Authors: Wiedemann, Falk R, Bartels, Claudius, Kirches, Elmar, Mawrin, Christian, Wallesch, Claus-W
• Format: Article
• Language: English
• Subjects: Aged; Ataxia; Biological and medical sciences; DNA, Mitochondrial - genetics; Electroencephalography; Electromyography; Gait Disorders, Neurologic - etiology; Gait Disorders, Neurologic - pathology; Hearing loss; Humans; Immunohistochemistry; Ischemia; Magnetic Resonance Imaging; Male; Medical sciences; MERRF; MERRF Syndrome - diagnosis; MERRF Syndrome - genetics; MERRF Syndrome - pathology; Middle Aged; Mitochondrial DNA; Muscle Weakness - etiology; Muscle Weakness - pathology; Muscle, Skeletal - pathology; Musculoskeletal system; Mutation; Mutation - physiology; Mutation analysis; Neurology; Neurosurgery; Ostomy; Phenotype; Prostaglandin-Endoperoxide Synthases - metabolism; Respiratory failure; Succinate Dehydrogenase - metabolism; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Ventilation
• ISSN: 0303-8467; 1872-6968
• DOI: 10.1016/j.clineuro.2008.06.010

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.