Enhancement of calcium influx through the GluR2 subunit of the α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) ionotropic glutamate receptor and the consequent excitotoxicity represent the main plausible hypotheses for selective neuronal death in ALS (Shaw and Ince 1997; Takuma et al. 1999; Kwak and Kawahara 2005). The gene discussed is GRIA2; the disease is amyotrophic lateral sclerosis.