A large body of experimental evidence has documented the role of aberrant function of components of the Rac1 signaling pathway in neurodevelopmental disorders, such as ID, however our current knowledge on Rac-GTPases function is obtained in vitro by overexpressing the constitutively active or dominant-negative Rac1 mutant proteins, which may have significant drawbacks10,11. This evidence concerns the gene RAC1 and neurodevelopmental disorder.