• Journal of Genetic Medicine
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• v.12 no.2
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• pp.109-117
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• 2015

Purpose: Mitochondrial diseases are clinically and genetically heterogeneous disorders, which make their exact diagnosis and classification difficult. The purpose of this study was to identify pathogenic mitochondrial DNA (mtDNA) mutations in 2 Korean families with myoclonic epilepsy with ragged-red fibers (MERRF) and Leigh syndrome, respectively. Materials and Methods: Whole mtDNAs were sequenced by the method of mtDNA-targeted next-generation sequencing (NGS). Results: Two causative mtDNA mutations were identified from the NGS data. An m.8344A>G mutation in the tRNA-Lys gene (MT-TK) was detected in a MERRF patient (family ID: MT132), and an m.9176T>C (p.Leu217Pro) mutation in the mitochondrial ATP6 gene (MT-ATP6) was detected in a Leigh syndrome patient (family ID: MT130). Both mutations, which have been reported several times before in affected individuals, were not found in the control samples. Conclusion: This study suggests that mtDNA-targeted NGS will be helpful for the molecular diagnosis of genetically heterogeneous mitochondrial diseases with complex phenotypes.

• Journal of Genetic Medicine
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• v.10 no.1
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• pp.20-26
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• 2013

Mitochondrion is an intracellular organelle with its own genome. Its function in cellular metabolism is indispensable that mitochondrial dysfunction gives rise to multisystemic failure. The manifestation is most prominent with tissues of high energy demand such as muscle and nerve. Mitochondrial myopathies occur not only by mutations in mitochondrial genome, but also by defects in nuclear genes or secondarily by toxic insult on mitochondrial replication. Currently curative treatment modality does not exist and symptomatic treatment remains mainstay. Administration of L-arginine holds great promise according to the recent reports. Advances in mitochondrial RNA import might enable a new therapeutic strategy.

• Pediatric Infection and Vaccine
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• v.30 no.2
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• pp.91-96
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• 2023

Infection with enterovirus (EV) 71 is usually associated with hand-foot-and-mouth disease and herpangina. The most frequent neurologic complication is brainstem encephalitis. A 30-month-old boy visited the pediatric emergency department with fever, lethargy, and abnormal eye contact. His mental status was slightly drowsy. On hospitalization day 2, the patient experienced respiratory arrest with apnea. Brain magnetic resonance imaging revealed bilateral symmetric T2-high signal lesions without enhancement in the posterior aspect of the brainstem and left medial temporal lobe. Electroencephalography was indicative of diffuse cerebral dysfunction with diffuse high amplitude and irregular delta activities. He underwent a gene study and was diagnosed with myoclonic epilepsy with ragged red fibers syndrome. We report a case of EV 71 brainstem encephalitis by polymerase chain reaction for nasopharyngeal aspirates and feces with rapid progression within one day of fever without the manifestation of throat and skin lesions because of his underlying mitochondrial disease.