CK23, or Keratin 23, type I, is a human gene encoded by KRT23. It may also be known as: Keratin, type I cytoskeletal 23; Cytokeratin-23; CK-23; Keratin-23; K23; HAIK1. The encoded protein has an amino acid length of 422 and a mass of 48.1 kDa. CK23 is a member of the Intermediate filament family. Homologs of this gene exist in other organisms, including: Mouse, Rat, Chicken.