Ornithine Aminotransferase (OAT)

Ornithine-delta-aminotransferase catalyzes the major catalytic reaction for ornithine. Ornithinemia presumably due to deficiency of ornithine ketoacid aminotransferase (OAT) was found in 9 patients with gyrate atrophy of the choroid and retina. The clinical history of gyrate atrophy is usually night blindness that begins in late childhood, accompanied by sharply demarcated circular areas of chorioretinal atrophy. During the second and third decades the areas of atrophy enlarge. Ornithine levels were 10 to 20 times higher than normal in plasma, urine, spinal fluid and aqueous humor. No consistent clinical abnormality other than the ocular one was found. Hyperammonemia was not found in the fasting state or after meals or stress testing. All the patients' parents were from the same geographic area of Finland.