RAC1 and autism: In a recent study with fruit flies (Drosophila melanogaster), Rac1 was a functional converging point for multiple autism risk genes, including Fragile X mental retardation 1 (FMR1), UBE3A, Neurexin-1 (Nrx-1), Neuroligin-4 (Nlg4), and Tuberous sclerosis complex 1 (TSC1).