IGF2 and fragile X syndrome: Experiments on rodents with artificial increase of systemic or local IGF-2 concentration, that was achieved either by an injection of the recombinant protein or by ectopic gene expression, demonstrated that IGF-2 may alleviate cognitive deficits in animal models of AD [20], ASD [111], Angelman syndrome [247], Fragile X syndrome [101], as well as aging-related cognitive decline [108].