Hyperornithinemia is an inborn disorder of ornithine metabolism due to mitochondrial ornithine aminotransferase deficiency.The main clinical manifestation of the disease is gyrate atrophy of the choroid and retina that begins during childhood with myopia and night blindness, followed by concentric shrinking of the visual field (tunnel vision) and a peculiar aspect of retinopathy on the funduscopy. The electroretinogram soon goes flat. Patients often develop subcapsular posterior cataract between the ages of 10 and 20 and become virtually blind between the ages of 40 and 50. Most patients have normal intelligence. The disease is Orphanet rare-disease nomenclature id Orphanet_414 (Gyrate atrophy of choroid and retina). Also known as: HOGA, Hyperornithinemia, Hyperornithinemia - gyrate atrophy of choroid and retina, Ornithine aminotransferase deficiency.