SLC6A17 is a synaptic vesicle transporter that mediates sodium-coupled, chloride-independent uptake of neutral amino acids, driven by the proton electrochemical gradient generated by vacuolar H(+)-ATPase 1. The transporter shows selectivity for proline, glycine, leucine, and alanine 1, and more recently glutamine has been identified as an endogenous substrate 2. SLC6A17 localizes to synaptic vesicles in glutamatergic and GABAergic neurons and likely contributes to neurotransmitter precursor uptake coupled to vesicle exocytosis. Pathogenic homozygous mutations in SLC6A17 cause autosomal-recessive intellectual developmental disorder 48 (IDRD48), characterized by moderate to severe intellectual disability with progressive tremor, speech impairment, and behavioral problems 3. Functional studies in knockout and mutant mice confirm learning deficits and establish decreased synaptic vesicle glutamine as a key pathogenic mechanism 2. Mutations cause either protein mislocalization or defective amino acid transport 32. Beyond neurological disease, SLC6A17 shows associations with skin pigmentation traits 4 and has emerged as a potential prognostic biomarker in lung adenocarcinoma, where elevated expression correlates with poorer survival outcomes 5. The gene also demonstrates dysregulation in preterm birth placentas 6.