Genetic inactivation of Vax1 in humans and mice causes agenesis of multiple midline structures of the brain, including the anterior commissure, the corpus callosum, and the OC, in addition to the coloboma of the eye (Bertuzzi et al., 1999; Hallonet et al., 1999; Slavotinek et al., 2012). Here, VAX1 is linked to coloboma.