Background: Gyrate atrophy of the choroid and retina (GACR) is an autosomal recessive metabolic disorder caused by mutations in the ornithine aminotransferase (OAT) gene.
Objectives: The aim was to assess the impact of vitamin B6 administration on the creatine amino acid level in the central nervous system (CNS) in patients with GACR.
 Patients and methods: This observational study included 10 patients with GACR aged 12 to 18 years old. All patients with B6-responsive GACR and evidence of creatine deficiency were included, regardless of outcome. Exclusion criteria involved non-responsive GACR, renal or hepatic impairment, or creatine supplementation. Patients were selected from Tanta and Sohag University hospitals between 2022 and 2023, and data were gathered through a retrospective review of medical records, including clinical details and investigations such as DBS amino acid profiles and creatine phosphokinase (CPK) assays before and after vitamin B6 administration at doses of 515 ± 62.58 mg/day (400–600 mg/day).
Results: Following vitamin B6 treatment, both ornithine and CPK levels significantly decreased (43.4%-53.9%, and 67.9%-70.1%, respectively). Additionally, citrulline and arginine levels significantly increased. When compared to pre-treatment values, the post-treatment creatine peak increased dramatically in the basal ganglia, frontal, and occipital regions of the cerebral cortex, respectively.
Conclusions: Vitamin B6 is a crucial component of the gyrate atrophy treatment regimen. It was effective in restoring the creatine level in the CNS and lowering ornithine levels. The MRS is a reliable tool for monitoring of patients with gyrate atrophy.