ARHGEF6 and Agenesis of corpus callosum: Two PAK3 variants responsible for severe ID and corpus callosum agenesis (G424R and K389N) were shown to suppress kinase activity, increase the interaction between PAK3 and the guanine exchange factor ARHGEF6 (Rac/Cdc42 guanine nucleotide exchange factor 6, also known as α-PIX), and inhibit cell migration [124].