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Hum Mol Genet. 2015 Apr 1;24(7):1869-82. doi: 10.1093/hmg/ddu604. Epub 2014 Dec 1.

A defect in early myogenesis causes Otitis media in two mouse models of 22q11.2 Deletion Syndrome.

Author information

1
Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK.
2
Ear Institute and Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 8XX, UK.
3
Institute of Genetics and Biophysics, National Research Council, and Department of Molecular Medicine and Medical Biotechnology, University Federico II, Naples 80138, Italy.
4
Department of Craniofacial Development and Stem Cell Biology, King's College London, London SE1 9RT, UK, abigail.tucker@kcl.ac.uk.

Abstract

Otitis media (OM), the inflammation of the middle ear, is the most common disease and cause for surgery in infants worldwide. Chronic Otitis media with effusion (OME) often leads to conductive hearing loss and is a common feature of a number of craniofacial syndromes, such as 22q11.2 Deletion Syndrome (22q11.2DS). OM is more common in children because the more horizontal position of the Eustachian tube (ET) in infants limits or delays clearance of middle ear effusions. Some mouse models with OM have shown alterations in the morphology and angle of the ET. Here, we present a novel mechanism in which OM is caused not by a defect in the ET itself but in the muscles that control its function. Our results show that in two mouse models of 22q11.2DS (Df1/+ and Tbx1(+/-)) presenting with bi- or unilateral OME, the fourth pharyngeal arch-derived levator veli palatini muscles were hypoplastic, which was associated with an earlier altered pattern of MyoD expression. Importantly, in mice with unilateral OME, the side with the inflammation was associated with significantly smaller muscles than the contralateral unaffected ear. Functional tests examining ET patency confirmed a reduced clearing ability in the heterozygous mice. Our findings are also of clinical relevance as targeting hypoplastic muscles might present a novel preventative measure for reducing the high rates of OM in 22q11.2DS patients.

PMID:
25452432
PMCID:
PMC4355021
DOI:
10.1093/hmg/ddu604
[Indexed for MEDLINE]
Free PMC Article

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