A new histone deacetylase inhibitor has shown promise for the treatment of Friedreich ataxia (FA). In cultured neurons derived from patients with FA, the drug was found to epigenetically modify transcription of FXN gene, thereby enhancing expression of frataxin protein. In a phase I trial comprising 20 patients, the drug upregulated acetylation of histone H3 lysine 9 and expression of FXN mRNA. No serious drug-related adverse events were observed.