In this issue of Molecular Pharmacology, Hahn et al. (p. 457) present a study of previously uncharacterized single amino acid variants of the human norepinephrine transporter. Intracellular trafficking, surface expression, transport properties, interaction with antagonists, and regulation by a protein kinase C-linked regulatory pathway were studied by heterologous expression in COS-7 cells. In recent years, there has been increasing focus on the natural variations and roles of nonsynonymous single-nucleotide polymorphisms in human membrane transporter genes (and their protein products) in human disease. As this information is assimilated and understood at the molecular and genetic level, the relationship between transporter pharmacogenomics and therapeutics in the age of individualized medicine will be greatly impacted.