– RGMa, also known as RGM domain family, member A, belongs to the RGM (repulsive guidance molecule) family whose members are membrane-associated glycoprotein. RGMa is a glycosylphosphatidylinositol-anchored glycoprotein that functions as an axon guidance protein in the developing and adult central nervous system. It helps guide Retinal Ganglion Cell (RGC) axons to the tectum in the midbrain. RGMa has been implicated to play an important role in the developing brain and in the scar tissue that forms after a brain injury. This protein may also function as a tumor suppressor in some cancers.