BMP4 and microphthalmia: The role of BMP4/7 heterodimers in eye development is likely conserved in humans since Bmp4 or Bmp7 are co-expressed in the developing human eye, and mutations in either gene are associated with anophthalmia, microphthalmia and chorioretinal coloboma (Bakrania et al., 2008; Wyatt et al., 2010).