To establish phenotype-genotype correlation regarding the location of missense mutations, Beryozkin et al.[27] have studied the phenotype of patients with homozygous missense mutations in CRB1. They found that patients with mutations within the Ca-binding EGF-like domains have more severe disease (LCA or early RP) compared to patients with homozygous missense mutations in the laminin AG-like domains. Here, CRB1 is linked to retinitis pigmentosa 1.