Stereocilia defect and loss of sensory hair cells of the Cdh23v-2J +/+ Pcdh15av-3J double heterozygote. Scanning electron micrographs of hair cell stereocilia in cochlea of 7-month-old mice. Stereocilia on the three rows of OHCs in a cochlea of a wild-type littermate B6 +/+ mouse (A) and of a +/Pcdh15av-3J single heterozygous mouse (B), with a normal, highly organized pattern, when compared with stereocilia of a Cdh23v-2J +/+ Pcdh15av-3J double heterozygous mutant mouse shown in (C). The single row of inner hair cells is seen in (C). Hair cells loss in the double heterozygous mutants underlies the disrupted appearance of the hair cell pattern. OHC, outer hair cell; IHC, inner hair cell. Scale bar, 5 μm.