The deafness causative gene is undoubtedly POU3F4, which causes the X-linked neurosensorial deafness DFN3. This defect is associated with either POU3F4 point mutations or small deletions in a region located at 900 Kb upstream of the gene and disturbing a regulatory element [9]. The gene discussed is POU3F4; the disease is X-linked mixed hearing loss with perilymphatic gusher.