Leigh's encephalomyelopathy is a metabolic disorder of infancy and childhood with a probably recessive mode of inheritance. Its course is remittent. Outstanding features are early and prominent neuro-ophthalmologic signs and psychomotor retardation. The former, with the remittent course, are highly suggestive of this disorder, while manifestations of the latter are nonspecific. Biochemical studies revealed diverse abnormalities. At necropsy, white and gray matter in many regions may be found affected, but there is predilection for symmetrical involvement of tegmental portions of the brain stem (abnormalities of ocular motility), optic nerves and tracts (visual deficits), and basal ganglia. Microscopically, there is myelin loss, necrosis, and capillary proliferation.
Borit A. Leigh's Necrotizing EncephalomyelopathyNeuro-ophthalmological Abnormalities. Arch Ophthalmol. 1971;85(4):438-442. doi:10.1001/archopht.1971.00990050440007