Evidence of active demyelination in a man with Leber's hereditary optic neuropathy mtDNA 14484 genotype

Leber's hereditary optic neuropathy (LHON) is an inherited form of bilateral optic atrophy. The predisposing genotype is a mutation in mitochrondrial DNA. Three primary mutations have been classified to date (11778, 3460, 14484). A multiple sclerosis-like illness has been described in some patients with LHON. The majority of these reports have been in patients with the 11778 mutation, although focal peripheral neurological signs and magnetic resonance imaging (MRI) changes consistent with demyelination have been documented in patients with the 3460 and 14484 mutations. The case report below describes a man with MRI and cerebrospinal fluid (CSF) evidence of multiple sclerosis and the LHON mitochrondrial DNA mutation at base pair 14484. This case report is only the third of a patient with the mtDNA 14484 mutation and evidence of multiple sclerosis and the first with any mutation that shows advancing radiological disease. Recent case reports and theories of aetiology are reviewed.