ALS2 mutations have been suggested to contribute to the pathogenicity of ALS through the disruptions of Rab5-dependent exocytosis, endosome trafficking and also glutamate-associated excitotoxicity, which is considered a hallmark of ALS pathology (Devon et al., 2006; Hadano et al., 2006; Lai et al., 2006). Here, RAB5A is linked to amyotrophic lateral sclerosis.