Audiological phenotyping evaluation in KBG syndrome: Description of a multicenter review

Our objective was to reinforce clinical knowledge of hearing impairment in KBG syndrome. KBG syndrome is a rare genetic disorder due to monoallelic pathogenic variations of ANKRD11.The typical phenotype includes facial dysmorphism, costal and spinal malformation and developmental delay. Hearing loss in KBG patients has been reported for many years, but no study has evaluated audiological phenotyping from a clinical and an anatomical point of view.

This French multicenter study included 32 KBG patients with retrospective collection of data on audiological features, ear imaging and genetic investigations.

We identified a typical audiological profil in KBG syndrome: conductive (71%), bilateral (81%), mild to moderate (84%) and stable (69%) hearing loss, with some audiological heterogeneity. Among patients with an abnormality on CT imaging (55%), ossicular chain impairment (67%), fixation of the stapes footplate (33%) and inner-ear malformations (33%) were the most common abnormalities.

We recommend a complete audiological and radiological evaluation and an ENT-follow up in all patients presenting with KBG Syndrome. Imaging evaluation is necessary to determine the nature of lesions in the middle and inner ear.