Otorhinolaryngologic manifestations of 22q11.2 deletion syndrome

Abstract

22q11.2 deletion syndrome (22q11DS) is caused by a microdeletion on chromosome 22. It occurs in approximately 1:3000-6000 live births. The aim of this thesis was to give an overview of otorhinolaryngologic manifestations in 22q11DS.

We performed a systematic review describing all otologic manifestations reported in 22q11DS in the literature thus far. We found 21 studies describing hearing loss and 21 studies reporting on other otologic manifestations. The range of hearing loss varied greatly, from 6.0 to 60.3%. The hearing loss was mostly conductive in origin. Recurrent or chronic otitis media was described in 2.2 – 89.8%. In our retrospective study we included 199 patients with 22q11DS who had visited our clinic, independently of symptoms. 102 patients had received an audiogram. 38% of ears had hearing loss, 94% of the ears with hearing loss were conductive in nature, and 4% were found to be mixed hearing losses. At time of most recent audiogram, 22,5% had a concomitant otitis media with effusion. 61% of patients had a history of tympanic membrane tube placement. 10% of patients used conventional hearing aids or a bone conduction device. We found no relation between age and hearing thresholds or otitis media. In addition, we analyzed radiologic images of the mastoid bones of 26 patients with 22q11DS. A dense stapes superstructure was present in 36% of ears, an incomplete partition type II of the cochlea in 23% of ears, a malformed lateral semicircular canal with a small bony island in 33% of ears and fusing of the lateral semicircular canal and vestibule to a single cavity in 29% of ears. In addition, the lateral semicircular canal is an important landmark for identifying the facial nerve during mastoid surgery. To avoid iatrogenic facial nerve damage otologic surgeons should be aware of this anomaly, perform a CT scan prior to surgery and use facial nerve monitoring during surgery in patients with 22q11DS.

Next, we performed a questionnaire study on vestibular symptoms. We found that children with 22q11DS experienced balance difficulties more often and were older when they started walking compared to children in the control group. Dizziness seemed not to be more frequently reported in children with 22q11DS.

Furthermore, we described 14 patients with 22q11DS and an airway malformation. We concluded that different types of airway malformations (choanal stenosis, pharyngo-, laryngo-, tracheo-, and/or bronchomalacie, tracheal stenosis, laryngeal web, laryngeal cleft, subglottic stenosis) can be present in 22q11DS. In five patients a vascular structure compressed the airway causing an airway malacia. There were three patients who required a tracheostomy. Clinicians should be aware of airway malformations in 22q11DS, and start early treatment if necessary. In addition, the diagnosis 22q11DS should be considered in patients with an (or more than one) airway anomaly.