Synapses and sisyphus: life without paraplegin

The family of neurodegenerative diseases known as hereditary spastic parapareses have diverse genetic loci, yet there is a remarkable convergence in the neuropathologic and neurologic phenotype. A report describing the construction of a transgenic mouse with a deletion of a nuclear-encoded mitochondrial protein involved in the regulation of oxidative phosphorylation suggests that this family of diseases may reflect activation of a final common pathway involving synaptic dysfunction that progresses to destruction of the presynaptic nerve terminal and axon (see the related article beginning on page 2 3 1).