The function of IRX5 (iroquois homeobox 5, ENSG00000176842) is as follows. Establishes the cardiac repolarization gradient by its repressive actions on the KCND2 potassium-channel gene. Required for retinal cone bipolar cell differentiation. May regulate contrast adaptation in the retina and control specific aspects of visual function in circuits of the mammalian retina (By similarity). Could be involved in the regulation of both the cell cycle and apoptosis in prostate cancer cells. Involved in craniofacial and gonadal development. Modulates the migration of progenitor cell populations in branchial arches and gonads by repressing CXCL12. {ECO:0000250, ECO:0000269|PubMed:22581230}.