Mutations affecting, for example, the superoxide dismutase 1 gene (SOD1) in amyotrophic lateral sclerosis (ALS) or DJ-1 [also known as parkinsonism associated deglycase (PARK7)] in Parkinson’s disease are located at the dimer interface, leading to dimer destabilization and subsequent protein aggregation. The gene discussed is SOD1; the disease is Parkinson disease.