SMAD2 and otitis media with effusion: MacArthur et al. (2014) reported associations at the SMAD2 and SMAD4 loci, mediators of the TGF-β signalling pathway, along with associations at the TLR4 and MUC5B loci. These studies are consistent with our findings on the underlying genes and pathways involved with OME in the mouse models Jf, Junbo and Tgif1, each of which carry a mutation in genes known to be involved in the regulation of the TGF-β signalling pathway.