Transcription factor probably involved in the development of the brain and the sense organs. Can bind to the bicoid/BCD target sequence (BTS): 5'-TCTAATCCC-3'. At Carnegie stage (CS) 14, widely expressed throughout the telencephalon and mesencephalon, with a sharp cutoff at the midbrain-hindbrain boundary. At CS16, found in the lamina terminalis and the floor of the telencephalon. At CS16-CS19, in the developing eye, strongly expressed in the retinal pigment epithelium layer and more weakly in the neural retina, not expressed in the optic nerve itself (at protein level). Retinal expression peaks between CS19 and CS21 and decline in older fetuses. At CS22, detected in the choroid plexus, the dorsal thalamus, and the roof of the mesencephalon. In the developing nasal structures, expressed in the olfactory epithelium of the nasal pits at CS18. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. Belongs to the paired homeobox family. Bicoid subfamily.