Interestingly, mutations in genes expressed in spiral ligament fibrocytes could affect stria vascularis function causing deafness, such as the ablation of the fibrocyte transcription factor POU3F4 that causes loss of fibrocytes IV and V in the spiral ligament, decreased cellular density in the stria vascularis and decreased expression of Kir4.1 (48). The gene discussed is POU3F4; the disease is deafness.