The members of the solute carrier family 5 (SLC5) originally classified as the sodium glucose cotransporter family, which are widely expressed in tissues ranging from epithelia to the central nervous system and transport myo-inositol, choline, iodide, and short-chain fatty acids, as well as carbohydrates. SLC5A9, which is also known as SGLT4, is expressed in the small intestine, kidney, liver, lung, and brain. It functions as a sodium-dependent transporter of D-mannose, D-glucose, and D-fructose.