ALDH1, or Aldehyde dehydrogenase 1 family member A1, is a human gene encoded by ALDH1A1. It may also be known as: Retinal dehydrogenase 1; RALDH 1; RalDH1; ALDH-E1; ALHDII; Aldehyde dehydrogenase family 1 member A1; Aldehyde dehydrogenase, cytosolic; retinaldehyde dehydrogenase 11; HEL-9; HEL-S-53e; HEL12; PUMB1; aldehyde dehydrogenase 1 family, member A1. The encoded protein is an enzyme with an amino acid length of 501 and a mass of 54.9 kDa. Other isoforms may exist. ALDH1 is a member of the Aldehyde dehydrogenase family. Homologs of this gene exist in other organisms, including: Mouse, Rat, Frog, Chicken.