IRS1 and deafness: We found eight genes that showed this pattern of expression: Snai2, Zeb1, Irs1, Nr3c1, Foxo1, Alk, Eln and Rad51. Three of these are known deafness genes: Snai2, which is involved in melanocyte development (Sanchez-Martin et al., 2002), Zeb1, which is required for the specification of mesenchymal identity and repression of epithelial identity (Hertzano et al., 2011), and Irs1 (DeMambro et al., 2010).