GRIA2 and amyotrophic lateral sclerosis: Moreover, it was shown that in the spinal motor neurons of patients with ALS, there was a defect in the GluA2 mRNA editing and significant downregulation of the Adenosine deaminase acting on RNA 2 (ADAR2) enzyme [140,141,142] that catalyses the Q/R editing of GluA2 and renders them impermeable to calcium [143].