SOD1 and amyotrophic lateral sclerosis: Interestingly, the prion-like paradigm of propagated SOD1 misfolding may explain the clinical observations of ALS disease progression, which suggests that motor neuron injury begins at one, or possibly more,9 focal points followed by progressive and contiguous spread of disease through the neuroaxis, i.e. pathology appears to spread without skipping neuroanatomical regions.10