Mitochondrial DNA 3243A>T mutation in a patient with MELAS syndrome

Approximately 80% of cases of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) harbor a heteroplasmic m.3243A>G transition in the tRNA Leu (UUR) ( MTTL1 ) gene. We report a MELAS case with a rare heteroplasmic m.3243A>T mutation found by direct sequencing of MTTL1 . This mutation has been previously reported in 5 cases, of which 2 cases had the MELAS phenotype. Our case also strengthens the hypothesis that the m.3243A>T mutation can cause the MELAS phenotype.