SLC25A48 is a mitochondrial inner membrane transporter that mediates choline import into the mitochondrial matrix 1. As a member of the SLC25 solute carrier family, SLC25A48 transports the water-soluble, charged choline molecule across the inner mitochondrial membrane, enabling its utilization in downstream metabolic pathways 2. Once imported, mitochondrial choline serves as a substrate for synthesis of betaine and other choline-derived methyl donors required for one-carbon metabolism and purine nucleotide biosynthesis 1. SLC25A48 is essential for maintaining mitochondrial function, including mitochondrial respiration, membrane integrity, and protein synthesis 13. Loss of SLC25A48 function impairs mitochondrial choline import and increases mitochondrial reactive oxygen species production and oxidative stress, resulting in impaired cell proliferation 1. In humans, loss-of-function mutations in SLC25A48 are associated with elevated plasma and urine choline levels, reflecting impaired mitochondrial choline uptake 24. Genome-wide association studies have identified SLC25A48 variants as genetic determinants of circulating choline levels and identified it in epigenomic analyses of Parkinson's disease subtypes 56. These findings suggest SLC25A48 dysfunction may contribute to metabolic and neurological diseases involving choline metabolism.