DYRK1A kinase triplication is the major cause of Otitis Media in Down Syndrome
Down syndrome (DS), which arises from trisomy of the whole or part of chromosome 21 (Hsa21), is one of the most common genetic abnormalities in humans. DS manifests as a broad spectrum of phenotypic features, including hearing loss due to otitis media with effusion (OME), affecting around 50% of children with DS. We employed a panel of mouse models of DS comprising a nested series of duplications covering the regions of the mouse genome syntenic to Hsa21 in order to define the loci involved with OME in DS. We identified a major locus on mouse chromosome 16, containing only 12 genes, that causes OME. Within this region we demonstrate that normalizing the gene dosage of Dyrk1a restored the wild-type phenotype. Investigation of downstream pathways of DYRK1A uncovered a number of pathological mechanisms whereby DYRK1A triplication leads to middle ear inflammation and vascular leak. These include cross-talk of DYRK1A and TGF{beta} signaling and its impact on proinflammatory cytokines IL-6 and IL-17, as well as raised VEGF levels in the middle ear accompanied by increased Hif1a. We conclude that DYRK1A is a potential therapeutic target for OME in children with DS.