Analysis of Auditory Phenotype and Karyotype in 200 Females with Turner Syndrome

Abstract

Turner syndrome is the most common sex chromosome disorder in females, and is caused by a total or partial deletion of one X chromosome. The purpose of this study was to describe the auditory phenotype in a large group of individuals with Turner Syndrome, with analysis focusing on hearing loss and age, as well as the phenotypic relationship to karyotype variation. Our analysis of auditory function was part of a large-scale, natural history study in which clinical and genetic factors related to Turner syndrome were examined. This ascertainment avoids the bias inherent in studies of patients referred to audiology or otolaryngology specialty clinics. Analysis included data from 200 females with Turner syndrome ranging in age from 7 to 61 yr (mean=27.9 yr). We observed hearing loss in approximately one-half of females with Turner syndrome, and report on a common, previously unlabeled audiometric configuration found in 24% of ears tested. Our cross-sectional design revealed an observable deterioration in hearing loss above the averaged rate of age-related hearing loss seen in an otologically screened, standardized population. Karyotype analysis revealed air conduction thresholds that were significantly poorer in the 46, XdelXp and 46, XiXq groups than in the 46, XdelXq group. This natural history study provides a more representative description of the auditory phenotype associated with Turner syndrome than previous studies that may have been biased by the method of ascertainment. Correlative analysis of Turner syndrome-specific hearing loss features with karyotype revealed that air conduction threshold elevations are associated with loss of the p arm of chromosome X. Our cross-sectional data indicate a loss of hearing sensitivity at an accelerated rate beyond a normal age-related decline, which warrants continued audiologic monitoring in all females with Turner syndrome regardless of a history of normal hearing.