SLC25A29 is a mitochondrial transporter of basic amino acids, primarily arginine and lysine, with secondary activity toward homoarginine, methylarginine, ornithine, and histidine 1. The transporter functions via both counter-exchange and uniport mechanisms 1, exhibiting high affinity for arginine and lysine while showing negligible carnitine/acylcarnitine transport activity 1. Physiologically, SLC25A29 facilitates basic amino acid import into mitochondria for protein synthesis and amino acid degradation 1. As the third mitochondrial ornithine transporter (ORNT3), it demonstrates partial functional redundancy with ORNT1, with enriched expression in the central nervous system and astrocytes 2, and can partially rescue ornithine transport deficiency in hyperornithinemia-hyperammonemia-homocitrullinuria syndrome 2. In cancer pathophysiology, SLC25A29 is significantly upregulated and promotes metabolic reprogramming toward glycolysis by increasing mitochondrial arginine import and nitric oxide synthesis 3. Elevated SLC25A29 enhances cancer cell proliferation and migration while suppressing oxidative phosphorylation 3. In prostate cancer, SLC25A29 functions as a high-risk prognostic biomarker for castration-resistant disease, operating through an E2F1/POLD1 axis linked to neuroendocrine differentiation 4. Genetic evidence implicates SLC25A29 as a novel susceptibility locus for type 1 diabetes through immune cell-mediated mechanisms 5.