SIX6 and coloboma: Because most of these genes were usually studied individually, and mutation analysis of Chinese patients is rare so far, we screened 32 unrelated patients with microphthalmia and/or coloboma for mutations in ten related genes, including BMP4, VSX2, CRYBA4, GDF6, OTX2, RAX, SIX3, SIX6, SOX2, and LRP6, through sequencing analysis of the coding and adjacent intronic regions of the ten genes.