Otologic characteristics of individuals with deletions of distal 18q

To fully describe the otologic features seen in individuals with deletions of the distal long arm of chromosome 18 (distal 18q-).

Cross-sectional/observational.

More than 200 individuals with deletions of the long arm of chromosome 18 underwent a complete otologic and audiologic examination. In addition, chromosome microarray analysis to determine the chromosome copy number was completed for all participants. Overall, 113 subjects had clinical and audiological data to be reported here.

Sixty-six percent of this population had aural stenosis or atresia. No subject had microtia. In the 53 individuals for whom serial data was available, enlargement of ear canal diameter was seen in 48% of ears with stenosis, examined over time. Abnormalities of the palate were seen in nearly 18% of patients and included complete or incomplete clefts of the palate, submucous clefts, and velopharyngeal insufficiency. A conductive hearing impairment was identified in 112 ears (49.5%), and sensorineural hearing loss was identified in 28%. Eustachian tube dysfunction was common and found in 78% of ears examined.

The otologic phenotype varies widely among individuals with distal 18q-. External auditory canal stenosis without microtia is a hallmark of the disease. Hearing impairment is also very common, with both sensorineural losses and conductive losses contributing to morbidity. Moreover, the critical region for sensorineural hearing loss will aid in the identification of the gene responsible for this aspect of the distal 18q- phenotype.

4.