Fig. 5. Mutations in vertebrate PCP genes lead to a PCP defect in the inner ear. Scanning electron micrographs of the inner ear from wild-type mice (A and B) and mice homozygous for mutations in a vertebrate homologue of flamingo (C), called crash (Crsh/Crsh). At (A) 3-5 months, wild-type stereocilia form regularly organized arrays, with the apex of the stereocilia pointing in one direction. This organization is evident in wild-type at E18.5 (B). In Crsh homozygotes at E18.5, the outer hair cells (OHCs) are extensively misrotated, showing a clear defect in PCP. Arrows show new axis of polarity. [Figure reproduced, with permission, from Curtin et al. (Curtin et al., 2003)].