FGF19 and Axenfeld-Rieger syndrome: Mutations in genes such as foxo1a and fgf19 have not been identified in ARS or glaucoma patients and thus the dysfunction of either gene alone likely cannot cause overt visual defects, however, their reduced expression due to loss of Foxc1 function, as well as other yet to be identified downstream targets, likely contribute to the complex etiology of RGC loss in FOXC1-attributable ARS patients.