Reduced anxiety has been reported in other ID mouse models, including Fmr1 and Mecp2 mutant mice and Down syndrome mouse models (Escorihuela et al., 1998; Peier et al., 2000; Altafaj et al., 2001; Samaco et al., 2008; Zang et al., 2009). This evidence concerns the gene FMR1 and Anxiety.