Hmx1 is required for the normal development of somatosensory neurons in the geniculate ganglion

► Hmx1 is a transcription factor linked to ear malformations in humans, rats, and mice. ► Hmx1 is expressed in somatosensory neurons, including all sensory modalities. ► The mouse “Dumbo” (dm) mutation is a complete loss of function for Hmx1. ► DRG neurons in Hmx1dm/dm embryos undergo neurogenesis normally. ► Hmx1dm/dm embryos have defects in the geniculate ganglion/posterior auricular nerve.