Thus given these results on the presence of SOD1-positive fibrillar aggregates in the spinal cord of SOD1-ALS mouse models, it is reasonable to speculate that the ‘seed’ responsible for seeding may be SOD1 pre-fibrillar aggregates present in the sample or produced from partial dissociation of the monomers from fibrils [48]. Here, SOD1 is linked to amyotrophic lateral sclerosis.