PAX2 and coloboma: Failure of basement membrane disintegration at the optic fissure margins has been reported as a cause of coloboma in a recent study of Fatty Liver Shionogi mice who present a phenotype similar to human ocular coloboma without microphthalmia, and also in two other coloboma models Pax2−/− and Vax2−/− mice (36–38).