SCNN1D is a subunit of the epithelial sodium channel (ENaC). ENaC has high sodium selectivity, low conductance, and amiloride sensitivity. The epithelial Na(+) channel (ENaC) regulates Na(+) homeostasis in cells and across epithelia; in the kidney, lung and colon it plays an essential role in trans-epithelial sodium and fluid balance. ENaC also mediates aldosterone-dependent sodium re-uptake in the distal nephron of the kidney, thus regulating blood pressure. Four homologous ENaC subunits (alpha, beta, gamma, and delta) have been isolated in mammals. Combination of alpha-, beta-, and gamma-subunits or delta-, beta-, and gamma-subunits forms fully functional channels. A delta subunit can replace the alpha subunit. However, the pharmacology, sensitivity to amiloride, conductance, and ionic selectivity of the delta/beta-gamma channel are different from those of the alpha/beta-gamma channel.