GRIK2 and glaucoma: Moreover, different subunits of glutamatergic receptors, e.g., GRIA1 and GRIK2, encoding the glutamate ionotropic receptor AMPA type subunit 1 and the glutamate ionotropic receptor kainate type subunit 2, respectively, identified as central nodes in the GSE133563 network, have not yet been associated with glaucoma pathogenesis.