EN2 and autism: In this context, several genes downregulated in the brainstem of Hoxa5 cKO mouse at P21, such as Grm4, Cbln1, En2, Camk4, and Cadps2, have been associated to autism traits either in humans or in mouse models (Sadakata and Furuichi, 2009; Becker et al., 2014; Waltes et al., 2014; Genestine et al., 2015; Krishnan et al., 2017).