CLCNKB encodes ClC-Kb, a voltage-gated chloride channel with selective anion permeability, particularly for chloride over bromide and nitrate 12. The channel forms homodimeric structures with independent ion conduction pathways per subunit, regulated by fast gates controlling each subunit individually and a slow common gate controlling both simultaneously 123. Assembly with the regulatory subunit Barttin (BSND) is essential for basolateral membrane trafficking and functional activation, producing predominantly linear current-voltage relationships 12. CLCNKB mediates chloride conductance in renal nephron segments, including the thick ascending limb of Henle's loop and collecting duct, maintaining systemic electrolyte and acid-base homeostasis 4. Additionally, it conducts chloride currents in the inner ear's stria vascularis, establishing the endocochlear potential necessary for normal hearing 56. CLCNKB mutations cause Bartter syndrome type 3 and can present with mixed Bartter/Gitelman phenotypes 78, with recent studies identifying CLCNKB as a biomarker in AKI-to-CKD progression 9. Mutations impair glycosylation and trigger distal tubular remodeling, leading to electrolyte imbalances and progressive kidney disease 10.