SIX6 and coloboma: Mutations in several genes have been reported in patients with microphthalmia and/or coloboma [3,9-14], including BMP4 (OMIM 112262), VSX2 (CHX10; OMIM 142993), CRYBA4 (OMIM 123631), OTX2 (OMIM 600037), RAX (OMIM 601881), SIX6 (OMIM 606326), and SOX2 (OMIM 184429).