Global deletion of IRSp53 in mice decreases dendritic spine density in the cortex and induces abnormal behaviors, including social-interaction deficits, hyperactivity, and cognitive impairments (Sawallisch et al., 2009; Chung et al., 2015), in line with the reported implication of IRSp53/BAIAP2 in ASD (Celestino-Soper et al., 2011; Levy et al., 2011; Toma et al., 2011), schizophrenia (Fromer et al., 2014; Purcell et al., 2014), and attention-deficit/hyperactivity disorder (ADHD; Ribasés et al., 2009; Liu et al., 2013). This evidence concerns the gene BAIAP2 and schizophrenia.