Mutations in the efnb1 gene that encodes ephrin-B1 are associated with CranioFrontalNasal Syndrome, characterized by hypertelorism, frontonasal dysplasia, coronal craniosynostosis, and mild learning disability (Twigg et al., 2004; Wieland et al., 2004). The gene discussed is EFNB1; the disease is frontonasal dysplasia.