HSM, or Leucine rich repeat containing 4B, is a human gene encoded by LRRC4B. It may also be known as: Leucine-rich repeat-containing protein 4B; Netrin-G3 ligand; NGL-3; LRIG4. The encoded protein has an amino acid length of 713 and a mass of 76.4 kDa. Other isoforms may exist. Homologs of this gene exist in other organisms, including: Rat.