SGK3 and schizophrenia: Results from our quadratic model implicated SGK3, a gene which encodes a serum- and glucocorticoid-inducible kinase (expressed in brain and previously associated with memory consolidation [54]), S100B, a gene which encodes a calcium-binding protein (highly expressed in glial cells and previously associated with dysfunctional calcium signalling in schizophrenia [55]), and C9orf4, a gene, which encodes a component of an AMPA receptor protein in the brain (a pathway involving glutamatergic signalling and found to be dysfunctional in schizophrenia [56]).