VSX2 and microphthalmia: VSX2 (Visual System homeobox 2, formerly known as CHX10) is a homeodomain containing transcription factor expressed in the developing retina in human [1], mouse [2], and zebrafish embryos [3,4]; VSX2/Vsx2 deficiency results in microphthalmia with various associated ocular anomalies in all three species [1-3], suggesting that the function of this gene is evolutionarily conserved.