PCDH15 and coloboma: Cadherin adhesion molecules are required for eye development, and variants in CDH23 and PCDH15 can lead to inherited eye disorders such as Usher syndrome.39 Developmental eye defects such as microphthalmia, cataracts, and microspherophakia and lack of retinal lamination have been previously shown in MO knockdown of cdh4 in zebrafish.22 Reduced dose knockdown of cdh4 in this study resulted in overall normal embryo development with no evident necrosis but a resultant coloboma phenotype.