SOD1 and amyotrophic lateral sclerosis: In summary, this study provides the earliest evidence of transcriptional dysregulation occurring in affected motor neurons of SOD1G93A mice in utero, supporting a potential perinatal origin of ALS as proposed by others.13 Our data highlight dysregulation of AMPA receptor Ca2+ permeability and RNA processing as very early and intrinsic events in the pathogenic cascade of mutant SOD1 (Fig. 8).