SLC35F4 is a solute carrier family member with dual proposed functions based on computational and experimental evidence. Primary studies indicate SLC35F4 likely functions as a Golgi-associated importer of flavin adenine dinucleotide (FAD), with molecular docking predictions showing high affinity (10-40 nM) for FAD 1. However, experimental characterization demonstrates that SLC35F4 also functions as a choline transporter with a Km of 12-50 µM, consistent with physiological plasma choline concentrations 2. This choline transport activity is inhibited by hemicholinium-3, decynium-22, and verapamil 2. Regarding tissue distribution, SLC35F4 shows restricted expression primarily in the cerebellum 1 and represents the highest mRNA expression levels in adult cerebellum tissue 3. The gene exhibits evolutionary significance, with adaptive haplotypes of Neanderthal ancestry identified in East Asian populations, suggesting positive selection related to thiamine metabolism approximately 10,000 years ago 4. Clinically, DNA methylation of SLC35F4 in nasal epithelium was associated with atopic asthma in children in a meta-analysis 5, though the mechanistic connection remains unclear. These findings collectively suggest SLC35F4 participates in both FAD homeostasis and choline-dependent neurotransmission, with potential implications for neurological and immune functions.