Homeobox protein OTX1 is a protein that in humans is encoded by the OTX1 gene. This gene encodes a member of the bicoid sub-family of homeodomain-containing transcription factors. The encoded protein acts as a transcription factor and may play a role in brain and sensory organ development. The Otx gene is active in the region of the first gill arch, which is related to the upper and lower jaw and two of the bones of the ear. A similar protein in mice is required for proper brain and sensory organ development and can cause epilepsy. Homeobox protein OTX2 is a protein that in humans is encoded by the OTX2 gene. This gene encodes a member of the bicoid sub-family of homeodomain-containing transcription factors. The encoded protein acts as a transcription factor and play a role in brain and sensory organ development. A similar protein in mice is required for proper forebrain development. Two transcript variants encoding distinct isoforms have been identified for this gene. Other alternative splice variants may exist, but their full length sequences have not been determined.