Complementary in vitro and in vivo studies revealed that two deafness-related missense mutations in PCDH15 (I108N and R113G; Fig 1C and 1D) severely disrupt binding of CDH23 EC1+2 (hereafter cdh23) to PCDH15 EC1+2 (pcdh15) [34–40]. The gene discussed is PCDH15; the disease is deafness.