Neurophysiological findings in SPG4 patients differ from other types of spastic paraplegia.

The authors examined 12 families with autosomal dominant hereditary spastic paraplegia for phenotypic characteristics predicting the underlying genotype. They found no clinical differences between patients with or without mutations in the spastin gene (SPG4). Motor evoked potentials and nerve conduction studies were almost normal in those with SPG4. In contrast, non-SPG4 families had prolonged central motor conduction times or marked peripheral neuropathy, or both.