GLI3 and Down syndrome: Finally, the human Sox2 gene homolog SOX2, together with FOXP2 (whose mutation causes language impairment), GLI3 (part of the network in Figure 6), RCAN1 (involved in the pathogenesis of Down’s syndrome) and other genes, belong to a set of genes whose enhancers or promoters harbor modern human single-nucleotide changes that appeared after the split from the Neanderthal/Denisovan lineage, and have been proposed to contribute to modern human-specific characteristics [64].