Interestingly, several association studies have identified ST8SIA2 (also known as SIAT8B) as a risk gene for several neurodevelopmental and psychiatric disorders, including autism spectrum disorder (ASD) (Anney et al., 2010), bipolar disorder (McAuley et al., 2012) and schizophrenia (Arai et al., 2006; Tao et al., 2007; McAuley et al., 2012). Here, ST8SIA2 is linked to bipolar disorder.