Leber's hereditary optic neuropathy - Case report.

Leber's hereditary optic neuropathy is the most common mitochondrial condition and is characterized by bilateral, painless, subacute visual loss that develops during young adult life. LHON is a rare condition and this lack of knowledge can make doctors suspect and treat for other causes of vision loss. Typically, a series of tests are performed to confirm LHON diagnosis or exclude any other conditions. We presented the case of two brothers, HB, of 40 years old and HF, of 38 years old, who presented with a decrease in visual acuity in both eyes. The patients had been diagnosed with optic atrophy of unknown cause a long time ago, but no further investigations were made. They were treated with corticosteroids, antioxidants and vasodilators, but with no significant benefit. A blood test of the mitochondrial DNA, a magnetic resonance imaging and an optic coherence tomography of the optic nerve and macula were part of the following assessment of our patients. The mitochondrial DNA analyses revealed the 3460 G>A mutation on the mtND1 gene in both patients. Based on the medical history, the fundus aspect, the optic coherence tomography and the paraclinical investigations of the diagnosis of Leber's hereditary optic neuropathy were established in both patients. We started the treatment with idebenone and we evaluated the patients after three months. ABBREVIATIONS: LHON = Leber's hereditary optic neuropathy, mtDNA = mitochondrial DNA, VA = visual acuity, CF = count fingers, OCT = optical coherence tomography, RNFL = retinal nerve fiber layer, GCL = ganglion cells layer, MS = multiple sclerosis, MRI = magnetic resonance imaging, MTI = magnetization transfer imaging, MTR = magnetization transfer ratio.