Twenty-one-year follow-up of variable onset MELAS syndrome with heteroplasmic nt3243A>G mtDNA mutation

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a maternally inherited mitochondrial disorder of which m.3243A>G is the most commonly associated mutation, resulting in an inability to meet the energy requirements of various organs. MELAS poses a diagnostic challenge owing to its multiple organ involvement and great clinical variability due to its heteroplasmic nature. We report three cases from a family who were initially misdiagnosed with myasthenia gravis or undiagnosed. Although there is no optimal consensus treatment approach for patients with MELAS because of the disease’s heterogeneity, our 21-year-long therapy regimen of l -arginine, l -carnitine, and coenzyme Q10 sup-plementation combined with dietary management appeared to provide noticeable protection from the symptoms and com-plications. Prompt early diagnosis is important, as optimal multidisciplinary management and early intervention may improve outcomes.