Probable transcription factor which exert its primary action widely during early neural development and in a very limited set of neurons in the mature brain. Defects in POU3F4 are a cause of deafness X-linked type 2 (DFNX2). A mixed type of deafness characterized by both conductive hearing loss resulting from stapes (perilymphatic gusher) fixation and progressive sensorineural deafness. Belongs to the POU transcription factor family. Class- 3 subfamily. Note: This description may include information from UniProtKB.