SRY (sex determining region Y)-box 18, or, SOX18, is a human gene. Other names include: Transcription factor SOX-18; HLTS; SRY (sex determining region Y)-box 18. The encoded protein has an amino acid length of 384 and a mass of 40.9 kDa. Other isoforms may exist. This gene shares homology with other species, including: Mouse, Rat, Zebrafish, Frog, Chicken.