Susceptibility to otitis might also be impacted by deficiencies in innate immune molecules, such as the microbial pattern recognition receptors Toll-like receptor 4 (TLR4) (MacArthur et al., 2006) and Toll-like receptor 2 (TLR2) (Leichtle et al., 2009), and the immune signaling molecule MyD88 (Hernandez et al., 2008). The gene discussed is TLR4; the disease is ear infection.