ROBO1 and congenital heart disease: Knockouts for Sema3, Nrp1, or PlxnD1 and Robo1 mutant mice show ventricular septal defects (VSDs) and outflow tract defects, suggesting dysfunction of these guidance pathways may contribute to congenital heart disease (CHD) (Gu et al., 2003; Gitler et al., 2004; Kruszka et al., 2017).