GTF2I and autism spectrum disorder: Although autism is often associated with decreased social interest, the increased sociability in I56i(–/–) mice can be related to its relationship with Gtf2i a factor whose gene is located on human chromosome 7 in a region that is deleted in cases if Williams–Beuren syndrome (Francke, 1999), a neurodevelopmental, autism spectrum disorder characterized by overfriendliness and an increased trust in strangers (Francke, 1999).