These phenotypes reflect what is seen in mice homozygous for severe mutant alleles of Mitf. As Mitf is expressed prominently in the RPE, its mutations lead to aberrant RPE development (Bharti et al., 2008; Bumsted and Barnstable, 2000; Hodgkinson et al., 1993; Nguyen and Arnheiter, 2000; Steingrímsson et al., 1996; Tsukiji et al., 2009) and to the development of an abnormally small eye (microphthalmia) associated with retinal degeneration (Möller et al., 2004; Smith, 1992; Smith and Hamasaki, 1994; Steingrímsson et al., 1996). This evidence concerns the gene MITF and microphthalmia.