SLC5A7 encodes a high-affinity sodium-coupled choline transporter that plays a critical role in cholinergic neurotransmission 1. The protein functions as an electrogenic, voltage-dependent transporter that uptakes choline from the synaptic cleft into presynaptic nerve terminals, representing the rate-limiting step for acetylcholine synthesis 1. This choline transport is essential for maintaining cholinergic signaling pathways, as demonstrated by studies showing SLC5A7 downregulation disrupts cholinergic synaptic signaling and reduces acetylcholine concentration 2. The transporter is predominantly localized in presynaptic terminal intracellular organelles and translocates to the plasma membrane upon neuronal activity. Pathogenic variants in SLC5A7 cause congenital myasthenic syndrome type 20 (presynaptic) and distal hereditary motor neuropathy type 7, both affecting neuromuscular transmission 13. The gene also appears to have tumor suppressor functions in colorectal cancer, where promoter hypermethylation leads to SLC5A7 downregulation and cancer progression 4. Additionally, SLC5A7 polymorphisms influence autonomic nervous system reactivity and infant self-regulation, particularly in respiratory sinus arrhythmia responses to stress 5. These findings establish SLC5A7 as essential for both cholinergic neurotransmission and broader physiological regulation.