SPG7 and hereditary spastic paraplegia: Most SPG7 mutations identified in HSP patients can potentially affect all isoforms, however two pathogenic mutations, one missense (A10S) and one affecting the first methionine, have been found in exon 1 [7], [27], arguing for the fact that it is sufficient to affect mitochondrial paraplegin to induce HSP, similarly to what occur in the mouse.