ST8SIA2 and schizophrenia: Moreover, in human patients and in animal models, several studies have shown alterations in polySia expression and genetic associations of NCAM1 and ST8SIA2 variants with schizophrenia (Varea et al., 2007; Anney et al., 2010; Brennaman and Maness, 2010; Gilabert-Juan et al., 2011; McAuley et al., 2012; Guirado et al., 2014b; Castillo-Gómez et al., 2016, 2017).