ISL1 and Anxiety: For instance, allele variants of NTRK3, PPP2R2B, and ESR1 were associated with anxiety in humans32–34, knock-out mice of Cacna1h, Rapgef2, Clstn2, and Tnr exhibited abnormal anxiety-like behaviors35–38, and Isl1, Abl2, Dlgap1 and Csmd2 knock-out mice showed alterations in neurodevelopment and behavior39–42.