The following etiologies of OA were also found but at lower frequencies: secondary to intracranial hypertension (8% of eyes), acute anterior ischemic optic neuropathy (7% of eyes), traumatic optic neuropathy (6% of eyes), toxic optic neuropathy (5% of eyes), optic disc drusen (3% of eyes), myelin oligodendrocyte glycoprotein optic neuritis (2% of eyes), anti-aquaporin-4 antibody positive optic neuritis (1% of eyes), and infectious optic neuropathy (0.8% of eyes). The gene discussed is AQP4; the disease is Optic disc drusen.