Potential alternative pore-forming subunit of the epithelial sodium channel (ENaC), capable of replacing the alpha/SCNN1A subunit, creating a more active channel with distinct properties (PubMed:16423824, PubMed:19520916, PubMed:22505667). ENaC functions in epithelial tissues, where it facilitates the electrodiffusion of sodium ions from the extracellular fluid through the apical membrane of cells, with water following osmotically, regulating sodium balance and fluid homeostasis (PubMed:16423824, PubMed:19520916, PubMed:7499195). This subunit could also function independently as a sodium channel or assemble into other tissue-specific heterotrimeric sodium channels (PubMed:7499195). {ECO:0000269|PubMed:16423824, ECO:0000269|PubMed:19520916, ECO:0000269|PubMed:22505667, ECO:0000269|PubMed:7499195}. [Isoform 2]: ENaC channels including this isoform exhibit greater conductance. . This is the function of SCNN1D (sodium channel epithelial 1 subunit delta, Ensembl gene identifier ENSG00000162572).