However, it has been demonstrated that single-organ gene therapy could successfully ameliorate the phenotype of MDs at least in two different conditions: the tissue-specific clinical presentation of mitochondrial dysfunction (e.g., LHON, a liver-specific mtDNA depletion syndrome due to mutations in MPV17) and multi-organ involvement due to the systemic accumulation of toxic compounds (e.g., ethylmalonic encephalopathy, mitochondrial neurogastrointestinal encephalomyopathy). The gene discussed is MPV17; the disease is myelodysplastic syndrome.