Long-term audiological feature in pendred syndrome caused by SLC26A4 mutation

Abstract

Objectives: Pendred syndrome is inherited as an autosomal recessive form and may account for 10% of hereditary hearing loss. It is likely that there is a great variation in hearing loss. We report a case of Pendred syndrome in which a mutation in SLC26A4 gene was detected and show the characteristics of long-term audiological changes. Methods: A 27-year-old woman was followed since March 1979 at Hamamatsu University School of Medicine. She first experienced vertigo at the age of 1 1/2 years and her parents were concerned about her poor response to sound. Mild hearing loss was diagnosed in another clinic at the age of 4 years. Results: Long-term audiological observation over 20 years showed that a 45 dB in the right ear and 41.2 dB in the left ear increased as the average threshold with fluctuation and marked progression combined with vertigo occurred before the age of 12. After that, the threshold moved to the stable. The audiogram indicated an asymmetric pattern and sensorineural hearing loss predominantly. A caloric test revealed a normal response on both sides. Corticosteroids were not effective in improving hearing loss. A diffuse goiter was noticed at the age of 15 years. The goiter slightly enlarged over the 12 years follow-up period. Conclusion: Although the His723Arg missense mutation is a change at unconserved position in the pendrin protein, it is a pathological mutation in our case because it was found in the homozygous state. It is possible that different mutations within the same gene lead to different phenotypes.