Ocular Tissue-Specific Amino Acid Metabolism in Gyrate Atrophy.

Deficiency of the mitochondrial enzyme ornithine aminotransferase (OAT) causes gyrate atrophy of the choroid and retina (GACR), a rare autosomal inherited disorder characterized by a substantial elevation in plasma ornithine and progressive chorioretinal degeneration. While OAT is expressed in many tissues, the deficiency mainly affects the retinal pigment epithelium (RPE)/choroid and retina, progressing from the periphery to the macula. RPE has been identified as the initial site of damage in GACR. Amino acid metabolism is crucial for the RPE function and its support for retinal metabolism. In GACR, in addition to ornithine, the metabolism of multiple amino acids is disrupted. This review explores the tissue-specific differences in amino acid metabolism between macular and peripheral ocular regions that may contribute to the pathophysiology of the disease.