Given that decreased spine density is the shared pathological change in DS and in some ASD mouse models, including Mecp2 knockout [55–57] and 15q11-13 duplication (Fig. 3), and that intellectual disability also occurs in a significant portion of ASD patients [5, 30, 66], it is interesting to consider the potential crosstalk between ASD genes and DS genes. This evidence concerns the gene MECP2 and Intellectual disability.