ZEB1 and posterior polymorphous corneal dystrophy: Herein, we present the results of sequencing the 5’ UTR and promoter region of OVOL2 in the family originally linked to the PPCD1 locus on chromosome 20, as well as in 26 PPCD probands in whom a ZEB1 truncating mutation was not identified.[13] We also report the results of copy number variation (CNV) analysis in the PPCD1 and PPCD3 loci to identify the cause of PPCD in individuals without either an OVOL2 or a ZEB1 5’ UTR, promoter, or coding region mutation.