The influence of karyotype on the auricle, otitis media and hearing in Turner syndrome.

The study has investigated the relationship between the chromosomal aberration and ear and/or hearing disorders in 115 girls/women with Turner syndrome (TS). A dose-response relationship was found between the karyotype and hearing function. Hearing deteriorated more rapidly with increasing age in TS women lacking the whole p-arm of chromosome X (i.e. monosomy 45,X, or isochromosome cases 46,X,i(Xq)) as compared to women having a partial deletion of the p-arm (structural deletions or mosaicism cases), who, in turn, had poorer hearing than a female random population sample (46,XX) (P<0.001). Moreover, TS subjects having total deletion of the p-arm were three times more likely to have auricular anomalies or conductive hearing loss due to otitis media than subjects with partial deletion (P<0. 05). The results support the hypothesis that lack of growth-regulating genes such as the short stature homeobox-containing gene (SHOX), which is located within the pseudo-autosomal region on the p-arm of the X chromosome, may increase the occurrence of auricular malformations and otitis media and also induce an earlier loss of hearing function. Accordingly, the ear and hearing disorders in TS may be a result of growth disturbances of the auricle, the mastoid, the Eustachian tube and the organ of Corti during development. It is suggested that karyotype may be used as a predictor for future ear and hearing problems in TS.