Progressive Longitudinally Extensive Myelopathy following Stroke in a Patient later found to have m.14484T>C Mutation in Leber’s Hereditary Optic Neuropathy (LHON) gene.
Kathryn Eszes1, Lawrence Samkoff2, Jordan Bontrager3
1University of Rochester Medical Center, Dept of Neurology, 2University of Rochester School of Medicine and Dentistry, 3Neuromuscular Disease Center, University of Rochester School of Medicine and Dentistry
Objective:
To present a unique case of progressive myelopathy following stroke and its relationship to subsequently revealed LHON gene mutation (m.14484T>C).
Background:
Leber’s Hereditary Optic Neuropathy (LHON) is a maternally inherited mitochondrial disease associated with acute or subacute bilateral painless vision loss. LHON can also present with non-optic nerve disorders, including longitudinal myelopathy and increased risk of multiple sclerosis, known as LHON plus or LHON-MS. LHON plus presenting as longitudinal myelopathy without preceding optic neuropathy has been rarely reported.
Results:
A 66-year-old woman with history of hypertension suffered an acute right hemispheric subcortical stroke at age 63 with resultant left sided hemiparesis. Months afterwards she began to experience progressive bilateral sensory symptoms and worsening hemiparesis, initially resembling Brown-Sequard syndrome. MRI demonstrated exuberant Wallerian degeneration of the corticospinal tract from the site of her stroke, extending through the brainstem to contralateral spinal cord. Extensive autoimmune, neoplastic, ischemic, and metabolic workups were largely unrevealing, aside from elevated ANA and vitamin B12 deficiency. Over the ensuing two years symptoms progressed to near-complete sensory loss of the lower extremities, right sided weakness, and ultimately development of orthopnea, intermittent diplopia, and dysphagia. This continued despite trials of high dose steroids and IVIG. MRI demonstrated new lesions in the contralateral medulla, bilateral posterior and lateral columns, and atrophy in previously affected areas. Whole exome sequencing revealed pathogenic homoplasmic m.14484T>C mutation in the MT-ND6 gene. Patient has never endorsed visual loss.
Conclusions:
This case adds to the few reports of myelopathy as the presenting feature of LHON. Unique in our patient is the absence of visual symptomatology after three years of disease onset, possibly expanding the spectrum of pathology resulting from MT-ND6 mutation.