SLC25A20 encodes the carnitine-acylcarnitine translocase (CAC), a mitochondrial inner membrane transporter that catalyzes the electroneutral exchange of acylcarnitines with free carnitine across the mitochondrial membrane 1. This transporter is essential for fatty acid β-oxidation, facilitating the transport of short, medium, and long-chain acylcarnitines into the mitochondrial matrix where they undergo oxidation 1. The protein utilizes an alternating access mechanism involving conformational transitions between cytoplasmic (c-state) and matrix (m-state) conformations 2. Functionally, SLC25A20 acts as a tumor suppressor by promoting fatty acid oxidation; its down-regulation in hepatocellular carcinoma leads to suppressed fatty acid oxidation, enhanced cell growth, and increased metastasis through mTOR pathway inactivation 34. Clinically, SLC25A20 mutations cause carnitine-acylcarnitine translocase deficiency (CACTD), a rare autosomal recessive disorder presenting with severe metabolic decompensation, hypoglycemia, and often neonatal death 56. Pathogenic mutations such as Asp231His and Ala281Val disrupt the transporter's conformational dynamics 2. SLC25A20 also functions as an immunologic regulator, with dysregulation linked to inflammatory conditions including ankylosing spondylitis and uveitis 7.