RARB and coloboma: Genes that encode transcriptional regulators (e.g., PAX2, PAX6, MITF, TFAP2A, and CHD7), members of secreted signaling pathways, such as transforming growth factor‐beta/bone morphogenetic protein (TGFB/BMP) signaling (BMP7, GDF3, and GDF6), Hippo signaling (YAP1), retinoic acid (RA) signaling (ALDH1A3, STRA6, and RARB) and those involved in membrane transport (ABCB6) have been implicated in causing coloboma when mutated in humans (Reis & Semina, 2015).