[Peripheral neuropathy in two children with mitochondrial encephalomyopathy].
Peripheral neuropathy (PN) associated with mitochondrial encephalomyopathy (MEM) has been reported in adult patients, while children with both conditions are rare. Electrophysiological and pathological studies disclosed evidence of PN in a 3-year-old girl and an 8-year-old boy with MEM. In both patients, peripheral nerve conduction velocities were reduced, while amplitudes of evoked potentials were normal. No ragged red fibers were found in the biopsy muscle, while most of the muscle fibers showed poor activity with histochemical staining for cytochrome c oxidase (CCO). Biochemical studies revealed deficiency of CCO in both cases. In the latter patient, CCO activity was also absent in the intramuscular peripheral nerve using CCO staining, and histopathological studies of the sural nerve revealed a marked decrease in the number of large myelinated fibers and an unusual accumulation of the mitochondria in the Schwann cell cytoplasm. These results may support the hypothesis that a common pathogenesis exists in both peripheral nerve and muscle due to mitochondrial dysfunction.
Tanaka
J
J
Department of Pediatrics, Osaka University Medical School.
Taniike
M
M
Inui
K
K
Nagai
T
T
Okada
S
S
D000367:Age Factors; D001927:Brain Diseases / Q000150:complications* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D030401:Cytochrome-c Oxidase Deficiency; D005260:Female; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D009135:Muscular Diseases / Q000150:complications* / Q000473:pathology; D009431:Neural Conduction; D010523:Peripheral Nervous System Diseases / Q000209:etiology*; D013497:Sural Nerve / Q000378:metabolism / Q000473:pathology