The second module comprises deafness genes whose expression level peaks in the mature cochlea (P16), and they encode proteins with very different roles than the deafness genes of the first module: the late-induced deafness genes carry out basic functions of the mature/fully-functional cochlea, mostly categorized with structural or neuronal function, including Gjb2, Oto2, Myo5, Ush1g, Grxcr2, Tmc1, Myo15, Ptprq, Loxhd1, Col4a4, Cacna1d, and Coch or neuronal associated, including Kcnq4, P2rx2, Slc26a4, Otof, and Cacna1d. The gene discussed is P2RX2; the disease is deafness.