SOD1 and amyotrophic lateral sclerosis: Of those available, mice overexpressingthe human mutant superoxide dismutase-1 (SOD1) gene are the best studied.5 However, it is now recognized that a lack ofsensitive biomarkers of disease has hampered ALS preclinical studies.6In vivo biomarkers presentlyin use include time-consuming gait analysis systems and phenotypescores,7 expensive imaging tools, suchas magnetic resonance imaging (MRI),8 andchallenging electrophysiological measures.9