文本框: A RARE FORM OF MELAS WITH OPTIC ATROPHY AND ITS CAUSAL LINK TO A POINT MUTATION OF THE MITOCHONDRIAL tRNALYS GENE, A8296G Sakuta R1, Murakami N1, Goto Y2, Nagai T1, Nonaka I2 1 Department of Pediatrics, Dokkyo University School of Medicine, Koshigaya Hospital, Japan 2 National Institute of Neuroscience, National Center of Neurology and Psychiatry, Japan Objective: We had a patient with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) presenting the unusual combination and investigated the mitochondrial DNA (mtDNA) mutations. Methods: A muscle biopsy specimen obtained from left biceps brachii muscle. Serial frozen sections were stained with H&E and a battery of histochemical methods. Total DNA was extracted from a part of the muscle biopsy. For sequencing analysis, 12 sets of primers were used to amplify the DNA fragments covering all of the mitochondrial tRNA regions. Patient: A 14-year-old Japanese boy was born by normal spontaneous delivery. At the age of 4 years, he was diagnosed as having optic atrophy. He developed persistent fatigue and weakness of skeletal muscles. Hypertrophic cardiomyopathy was found at 10 years old. At the age of 14, he had an episode of headache with nausea accompanied by focal motor and generalized epileptic seizures. Results: The nucleotide sequence analysis of the total mtDNA fraction revealed a point mutation in the tRNALYS gene substituting A at 8296 to G (A8296G). Pathological examinations of the skeletal muscles showed clear characteristics of MELAS. Conclusion: The A8296G mutation was previously identified among patients with diabetes mellitus or myoclonus epilepsy with ragged-red fibers (MERRF), however, not those with MELAS. This study indicates that the A8296G mutation can play a causal role not only for diabetes mellitus and MERRF but also for MELAS. 1902