Expression of these proteins is spatially and temporally regulated during embryonic development.

The homeobox protein Hox-A1 may be involved in the placement of hindbrain segments in the proper location along the anterior-posterior axis during development.

[8] A common polymorphism in the HOXA1 gene is associated with a susceptibility to autism spectrum disorder, with individuals possessing these gene variant have an approximately doubled risk of developing the disorder.

[9] Studies on knockout mice have indicated that the gene can alter embryological development of the brain stem (specifically the facial and superior olivary nuclei), as well as induce several other physical changes such as in ear shape.

[12] This article incorporates text from the United States National Library of Medicine, which is in the public domain.