The phenotypes we observed in homozygous Slc25a21tm1a(KOMP)Wtsi mice were broadly consistent with those reported previously in mice carrying hypomorphic Pax9 alleles [26] with the exception that the otitis media and hearing impairment reported in this study have not been assessed previously in Pax9 mutant mice and may represent a novel consequence of Pax9 suppression. The gene discussed is PAX9; the disease is otitis media.