SLC4A4 (Solute Carrier Family 4 Member 4) is a gene that encodes a sodium bicarbonate cotransporter involved in regulating the body’s acid-base balance. Predominantly expressed in the kidneys and pancreas, it plays a crucial role in bicarbonate reabsorption and pH regulation. Disruptions in SLC4A4 function can impair the body’s ability to maintain acid-base homeostasis, contributing to conditions such as renal tubular acidosis.