At the same time, murine Pax6 was also identified by the screening of mouse embryonic expression libraries [3] and associated as the causal gene of an heterozygous Sey mouse strain (Sey+/−) [4], which presented with microphthalmia, iris hypoplasia, cataracts, and corneal opacifications, resembling human developmental eye disorder aniridia [5]. The gene discussed is PAX6; the disease is isolated aniridia.