As major causative genes for simple microphthalmia, CHX10 (Ceh10 homeodomain gene; OMIM 142993), PAX6 (Paired box gene 6; OMIM 607108), and MFRP (Membrane-type frizzled-related protein; OMIM 606227) probably induce the failure of ocular differentiation [4-6]. The gene discussed is VSX2; the disease is microphthalmia.