Neuropathological findings in a 59-year-old male case of hereditary spastic dystonia with Leber's hereditary optic atrophy included: marked depletion of myelinated nerve fibres in the posterior funiculi, corticopontine tracts and striatum; practically complete neuronal depletion in the putamen and lateral part of the caudate, and mild cell loss in the substantia nigra. The putamina had changed into a spongy fibrillary scar, the pallidal fibres and laminae were practically all degenerated. Moreover, there was generalised mild fibre degeneration of the white matter. The optic nerve showed marked, predominantly central, loss of nerve fibres with demyelination.