Proper morphogenesis of inner ear semicircular canals requires precise 
regulation of cellular proliferation, epithelial-to-mesenchymal transition, and 
fusion of epithelial plates. Epigenetic regulation of these processes is not 
well understood, but is likely to involve chromatin remodeling enzymes. CHD7 is 
a chromodomain-containing, ATP dependent helicase protein that is highly 
expressed in the developing ear and is required for semicircular canal 
development in both humans and mice. Here we report that mice with heterozygous 
loss of Chd7 function exhibit delayed semicircular canal genesis, delayed 
Netrin1 expression and disrupted expression of genes that are critical for 
semicircular canal formation (Bmp2, Bmp4, Msx1 and Fgf10). Complete loss of Chd7 
results in aplasia of the semicircular canals and sensory vestibular organs, 
with reduced or absent expression of Otx1, Hmx3, Jagged1, Lmo4, Msx1 and Sox2. 
Our results suggest that Chd7 may have critical selector gene functions during 
inner ear morphogenesis. Detailed analysis of the epigenetic modifications 
underlying these gene expression changes should provide insights into 
semicircular canal development and help in the design of therapies for 
individuals with inner ear malformations.