Abstract:

The m.3302A>G mutation in the mitochondrial tRNA(Leu(UUR)) gene has been identified in only 12 patients from 6 families, all manifesting adult-onset slowly progressive myopathy with minor central nervous system involvement. An 11-year-old boy presented with progressive proximal-dominant muscle weakness from age 7years. At age 10, he developed recurrent stroke-like episodes. Mitochondrial myopathy, encephalopathy, lactic acidosis, plus stroke-like episodes (MELAS) was diagnosed by clinical symptoms and muscle biopsy findings. Mitochondrial gene analysis revealed a heteroplasmic m.3302A>G mutation. Histological examination showed strongly SDH reactive blood vessels (SSVs), not present in previous cases with myopathies due to the m.3302A>G mutation. These findings broaden the phenotypic spectrum of this mutation.

日本語要旨:

m3302A>G変異はこれまでに、6家系12 の患者で報告されているのみであり、その病型は、 全員成人発症の進行性ミオパチーに軽度の中枢神経障害を伴うものであった。今回、同変異を有する11歳男児で、MELASの臨床型を示す例を見出した。筋病理ではSSVを見出した。