Role of hoxa1 in mammalian hindbrain, inner ear and neural crest development

Homeobox transcription factors belong to a family of proteins involved in an array of developmental processes, the most important being specification of the anteriorposterior axis of the embryo. The first and one of the most anteriorly expressed Hox genes during development is Hoxa1. Mouse knockout studies have revealed that loss of Hoxa1 function leads to mispatterning of the hindbrain, in addition to defects in the inner ear, cranial ganglia, and the breathing inducing cells in rhombomere 3. More recently, humans with homozygous mutations in Hoxa1 have been identified, which sparked new interest in understanding the role this crucial transcription factor plays during development. Interestingly, human patients in addition to the defects described in mice, also display cardiovascular abnormalities.