Therefore, molecular and biochemical analysis could help in the differential diagnosis.[11] OAT is a homohexameric enzyme which has a vital role in proline and GABA synthesis from ornithine and arginine.[12] The OAT enzyme deficiency caused by different mutations in the OAT gene leads to hyperornithinemia and chorioretinal degeneration. This evidence concerns the gene OAT and Chorioretinal atrophy.