Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is characterized by a mitochondrial DNA mutation that leads to defective taurine modification of the leucine tRNA anticodon, with consequent impaired translation of the UUG codon. This defect reduces synthesis of respiratory chain complexes, which causes energy failure. Taurine supplementation improved mitochondrial function in MELAS model cells. A physician-initiated clinical trial reported that high-dose taurine supplementation therapy suppressed stroke-like episodes and improved taurine modification rates in leukocytes.