Morphogenetic defects underlie Superior Coloboma, a newly identified closure disorder of the dorsal eye
Fig 10
Model of superior ocular sulcus morphogenesis and function.
The superior ocular sulcus appears as a narrow groove in the dorsal retina soon after optic cup formation (22 hpf), and subsequently becomes wider (24 hpf). The DRV grows through the wide sulcus as it travels across the dorsal retina towards the lens (24–26 hpf). If BMP signaling is reduced, the sulcus persists as a deep and narrow structure, through which the DRV still travels. However, in low BMP conditions, the DRV has a thin and unbranched morphology as it traverses the deeper fissure, and then enters the divot at the inferior edge of the sulcus and forms an ectopic connection with the hyaloid vessels. If Sonic Hedgehog signaling is reduced, the SOS is absent at the time of DRV growth, resulting in the formation of more DRV vessels spread across the dorsal retina.