Gyrate Atrophy of the Choroid and Retina Diagnosed in Adulthood With a Homozygous OAT Variant: A Case Report Highlighting the Need for Long-Term Care.

Abstract

Purpose: The purpose of this study is to report a case of gyrate atrophy of the choroid and retina (GA) in a patient with a homozygous OAT variant who was unable to continue treatment due to loss to follow-up.

Case presentation: A 21-year-old female patient (JU1902) from South Asia was referred to The Jikei University Hospital for clinical and genetic evaluation. She underwent comprehensive ophthalmic examinations and whole-exome sequencing. Genetic analysis identified a homozygous variant in the OAT gene: a c.272G > A (p.Gly91Glu). Fundus photography showed sharply demarcated circular areas of chorioretinal atrophy in the peripheral retina. Fundus autofluorescence imaging revealed hypoautofluorescence corresponding to these atrophic areas. Optical coherence tomography showed multiple intraretinal cystic spaces with preservation of the outer retinal layers, including the ellipsoid zone. Goldmann perimetry revealed a markedly constricted visual field, with the I-2 isopter restricted to less than 5° and the I-4 isopter within 10°-20°. Full-field electroretinography demonstrated norecordable responses under all stimulus conditions. Biochemical testing indicated markedly elevated serum and urinary ornithine concentrations. Following the genetic and clinical diagnosis, vitamin B6 supplementation was initiated at 100 mg/day. However, serum ornithine levels remained markedly elevated. Although an increased dosage of vitamin B6 (200 mg/day) and an arginine-restricted diet were considered, the patient voluntarily discontinued follow-up visits and was subsequently lost to follow-up.

Conclusion: This case highlights the importance of continued treatment and follow-up in adult patients with GA. Forming a patient-centered multidisciplinary team, including professional interpreters and cultural liaisons, is essential for ensuring patient understanding, treatment adherence, and long-term visual preservation.