HN, or Mitochondrially encoded 16S RNA, is a human gene encoded by MT-RNR2. It may also be known as: Humanin; Humanin mitochondrialM; formyl-humanin; MTRNR2; l-rRNA. The encoded protein has an amino acid length of 24 and a mass of 2.7 kDa. Other isoforms may exist. HN is a member of the Humanin family. Homologs of this gene exist in other organisms, including: Fly.