SLC19A2 is a high-affinity thiamine transporter that mediates H(+)-dependent uptake of thiamine and pyridoxine, essential B vitamins serving as enzymatic cofactors in energy metabolism, protein and nucleic acid biosynthesis, and neurotransmitter production 1. The protein contains 12 transmembrane domains and is expressed throughout the gastrointestinal tract, with highest expression in liver, playing a role in intestinal thiamine absorption 2. Structurally, SLC19A2 translocates diverse substrates including thiamine, pyridoxine, and various drugs like metformin and fedratinib through outward- and inward-facing conformations 1. Beyond nutrient transport, SLC19A2 forms a heterodimer with the ion channel Tmem63b to induce phospholipid scrambling upon calcium stimulation, suggesting additional cellular regulatory functions 3. Clinically, mutations in SLC19A2 cause thiamine-responsive megaloblastic anemia syndrome, characterized by anemia, diabetes, and visual disturbances that respond dramatically to thiamine supplementation, though advanced neurological damage may be irreversible 45. The transporter represents a critical nutrient acquisition system whose dysfunction results in severe neurometabolic disease 1.