SLC7A4, also known as cationic amino acid transporter 4 (CAT4), is a member of the cationic amino acid transporter/glycoprotein-associated family, and it has been suggested to transport cationic amino acids, including arginine, lysine, and ornithine. The SLC7A4 gene has been mapped to chromosome band 22q11.2, which is deleted in the case of velo-cardio-facial syndrome, characterized by a cleft palate, heart defects, abnormal facial structure, and learning problems.