We therefore analysed mouse embryos of WT and Netrin-null (Ntn1-/-; Yung et al., 2015) littermates at embryonic stages after OFC completion (E15.5-E16.5) (Hero, 1990) and observed highly penetrant ocular coloboma in Ntn1-/- mutants (>90%; n = 10/11; Figure 4f). The gene discussed is NTN1; the disease is coloboma.