SMOC proteins are localized to BMs in various developmental contexts (Vannahme et al., 2002, 2003), and SMOC1 has been suggested as a fusion-specific BM-modulating factor due to causative mutations identified in patients and animal models with colobomas (Rainger et al., 2011; Patel and Sowden, 2017). This evidence concerns the gene SMOC1 and coloboma.