SOD1 and amyotrophic lateral sclerosis: The finding of iHg in corticomotoneurons and in other neurons implicated in ALS (Pamphlett and Kum Jew 2016) raises the possibility that iHg exerts its neurotoxic effect by binding to cysteine that forms the intra-superoxide dismutase 1 disulphide bonds, thereby preventing its normal folding and leading to misfolded forms of the protein (Sea et al. 2015); this has been found in the spinal cord in both familial and sporadic ALS (Gruzman et al. 2007) and by this mechanism iHg could produce a neurotoxic phenocopy of superoxide dismutase 1-mutant ALS.