The largest published cohort study to date identified ZEB1 mutations in 25% of PPCD cases (8/32 probands) (Aldave et al., 2007), with reported detection rates varying significantly across studies (9.1%–45.4%) (Aldave et al., 2007; Dudakova et al., 2019). This evidence concerns the gene ZEB1 and posterior polymorphous corneal dystrophy.