To study the effectiveness of gene perturbations in HF-iCas9 stem cells, we targeted several genes linked to Leber congenital amaurosis (LCA), a rare childhood-onset retinal dystrophy caused by mutations in the AIPL1, CRB1, and RPGRIP1 genes, among others. The gene discussed is CRB1; the disease is Leber congenital amaurosis.