Antituberculosis medication as a possible epigenetic factor of Leber's hereditary optic neuropathy

Purpose:  To investigate if antituberculosis medication including ethambutol could be a possible epigenetic factor in visual loss in Leber's hereditary optic neuropathy (LHON). Methods:  The authors reviewed the medical records of 46 patients registered at Bundang Seoul National University Hospital from 2002 to 2006, who developed the typical clinical neuro-ophthalmologic features of LHON and possessed a mtDNA mutation at nucleotide 11778, 14484, 3460 or 4171. Results:  Three of the 46 patients developed visual loss while taking antituberculosis medication. These three patients had the mtDNA 11778 mutation with a mean age of 32.7 years at the onset of visual loss, whereas the mean age of other 43 patients was 21.2 years. One of these three patients was female. Conclusion:  Antituberculosis medication may be an epigenetic factor of LHON in patients with a primary LHON mutation. This risk should be recognized by physicians and LHON carriers.