SHANK1 is associated with autism spectrum disorders (ASD). In the majority of the cases, patients with ASD carrying deletion of SHANK1 have no intellectual deficiency and no language delay. Penetrance of SHANK1 deletion for ASD seems to be higher in male than females. Female carriers of SHANK1 deletion often exhibit anxiety disorders without ASD. Additional clinical traits can co-exist such as anxiety disorders, attentional problems, sleep perturbation as well as developmental delay in motor functions.