Late-onset Leber's hereditary optic neuropathy presenting with longitudinally extensive myelitis harbouring the m.14484T>C mutation: Extending the genotype-phenotype spectrum.

Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease leading to visual loss, typically in young men, and rarely displays extra-ocular manifestations including spinal cord disease. We report the case of a 57-year-old man who presented with a longitudinally extensive dorsal column lesion as the first manifestation of LHON, with the onset of bilateral progressive optic neuropathy 11 months later, harbouring the m.14484T>C mutation. To our knowledge this is the most extensive cord lesion preceding optic neuropathy traversing the cervical and thoracic cord. We review the literature of all published cases of LHON in which spinal cord involvement was the presenting feature of the disease, summarising the clinical phenotype, demographics, radiological characteristics and genotype. We highlight the importance for diagnostic vigilance in patients with either longitudinally extensive dorsal column myelopathy, optic neuropathy or both.