No differences were seen in the degree of chronic neurodegeneration in the primary motor cortex, corticospinal tracts, hypoglossal nucleus or ventral grey matter of the cervical or lumbar spinal cord when comparing ALS patients with TIA1 mutations, C9orf72 mutations and sALS without either mutation (LMN counts shown in Fig. 4a). This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.