ARHGEF9 and Intellectual disability: Specific RhoGEFs have been implicated in neurodevelopmental disorders, such as language impairment (ARHGEF19), intellectual disability (ARHGEF6, ARHGEF2), and moderate intellectual disability with speech delay (ARHGEF9) (Kutsche et al., 2000; de Ligt et al., 2012; Nudel et al., 2014; Ravindran et al., 2017).