SLC30A8 encodes a zinc transporter (ZnT8) that functions as a proton-coupled zinc antiporter mediating zinc entry into pancreatic beta cell secretory granules, thereby regulating insulin storage and secretion 1. This zinc transport activity is essential for normal insulin processing and glucose homeostasis 1. The common polymorphism rs13266634 (C/T) is among the most confirmed genetic markers of type 2 diabetes (T2D) across multiple populations 2. Each C-allele confers approximately 14% increased T2D risk 2, with population-attributable risk of 9.5% in Europeans and 8.1% in East Asians 2. This non-synonymous variant causes a tryptophan-to-arginine switch at position 325, reducing zinc transport activity and decreasing intragranular zinc levels 3. The C-allele is also associated with gestational diabetes mellitus susceptibility 4. Notably, rare loss-of-function SLC30A8 variants demonstrate protective effects against diabetes 5, suggesting a complex dose-dependent relationship. SLC30A8 expression is downregulated in diabetic pancreatic islets, with increased DNA methylation observed in T2D patients 5. Additionally, SLC30A8 serves as an antigenic target in type 1 diabetes 5, expanding its clinical relevance beyond T2D.