Members of the RhoGEF protein family are implicated in glutamatergic synaptic deficits associated with neurodevelopmental disorders (Volk et al., 2015; Katrancha et al., 2017), and recent exome-sequencing studies have identified autism and schizophrenia-associated de novo missense mutations in Tiam1 and Tiam2 (Need et al., 2012; Takata et al., 2013; S. Lu et al., 2022). Here, TIAM2 is linked to autism.