Mutations in components of the MAPK signaling pathway, termed the RASopathies, produce numerous neurodevelopmental disorders, including autism (Adviento et al., 2014; Levitt and Campbell, 2009), and the MAPK3 gene has been suggested to contribute to the head size changes in 16p11.2 individuals (Shinawi et al., 2010). Here, MAPK3 is linked to RASopathy.