FZD5 and coloboma: Conditional loss of function of Fzd5 in the mouse eye leads to microphthalmia, coloboma and persistent foetal vasculature (Liu and Nathans, 2008), phenotypes that are exacerbated when the function of Fzd8, co-expressed with Fzd5 in the eye primordium, is downregulated (Liu et al., 2012).