Mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria is characterized by the association of a mitochondrial encephalomyopathy and an aminoacidopathy. It has been described in two brothers presenting with developmental delay, neurological signs, deafness, exercise intolerance, lactic acidosis and elevation of several plasmatic amino acids. Mitochondria morphology was found to be abnormal on muscle biopsy. Transmission is likely to be linked to maternal mitochondrial DNA. The disease is Monarch Disease Ontology term MONDO_0012791 (mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria). Also known as: booth-Haworth-Dilling syndrome, mitochondrial DNA depletion syndrome 5, mitochondrial DNA depletion syndrome type 5, mitochondrial encephalomyopathy-aminoacidopathy syndrome, mtDNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria.