MT-TF and lactic acidosis: Mutations in MTTF cause multiple mitochondrial respiratory chain deficiency and have been associated to a variety of clinical presentations, including Myoclonic Epilepsy with Ragged-Red fibers (MERRF) [1], rhabdomyolysis [2], Mitochondrial Encephalomyopathy, Lactic Acidosis with Stroke-like episodes (MELAS) [3], juvenile myopathy, encephalopathy, lactic acidosis and stroke [4], and recently to a neurodegenerative disorder with psychiatric disturbance, dementia and akinesia-rigidity (m.586G > A MTTF mutation) [5].