GRIK2 and amyotrophic lateral sclerosis: Multiple GWAS studies have described ALS-specific gains and losses in several genes encoding proteins involved in synaptic transmission and the regulation of neuronal action potential (KCNIP4, KCNB2, KCNQ5, GRIK1, GRIK2, ATXN1, BAIAP2, CPLX1, CACNA1H, SLC1A7) (Tables 1 and 2 and Supplementary Table 1) [110, 117].