MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes) is a disease mainly due to a mutation at position 3243 (A G) in the leucine tRNA gene in mitochondrial DNA. Symptoms of the disorder are complex and the exact pathogenesis is not understood. A review of the literature on the subject is presented.
E. Bartnik, Department of Genetics, University of Warsaw and Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5a, 02-106 Warszawa, Poland, e-mail: firstname.lastname@example.org