ZEB1 and posterior polymorphous corneal dystrophy: With the current report of five novel ZEB1 mutations in 13 probands with PPCD, the total number of reported mutations identified in ZEB1 associated with PPCD increases to 24, and the percentage of probands with PPCD in whom a ZEB1 coding region mutation has been identified increases to 32% (25/78) [7,8,10-12].