SCNN1A (Sodium Channel Epithelial 1 Subunit Alpha): SCNN1A is a gene that encodes the alpha subunit of the epithelial sodium channel (ENaC), which regulates sodium balance and fluid homeostasis in tissues such as the lungs, kidneys, and colon. This subunit is essential for ENaC’s assembly, localization, and function, enabling sodium absorption that supports blood pressure, fluid volume, and electrolyte balance. Mutations in SCNN1A can alter channel activity and are linked to conditions such as pseudohypoaldosteronism type 1 (PHA1), a disorder affecting salt regulation.