MYOCLONIC EPILEPSY WITH RAGGED-RED FIBERS (MERRF) - AN IMMUNOHISTOCHEMICAL STUDY OF THE BRAIN

Myoclonic epilepsy with ragged-red fibers (MERRF) is a maternally inhe rited disorder of oxidative phosphorylation due to specific point muta tions within the mitochondrial tRNA(Lys) gene. Mitochondrial dysfuncti on in the central nervous system (CNS) of patients with MERRF accounts for the neurological manifestations of the disease. Antibodies agains t subunits of complex I, III, IV and V of the respiratory chain were u sed to study the expression of these proteins in the frontal cortex, c erebellum and medulla from an autoptic case of MERRF. We found a selec tive decreased expression of subunit II of cytochrome c oxidase (COX-I I) in these regions. Immunohistochemical abnormalities were more wides pread than the lesions described by traditional histopathological tech niques and made possible an attempt of explanation for the neurologica l symptoms of the patient.