Clinical characteristics and genotype–phenotype correlation of hearing loss patients with SLC26A4 mutations

Abstract

Conclusions. The present study confirmed the clinical characteristics of patients with SLC26A4 mutations: congenital, fluctuating, and progressive hearing loss usually associated with vertigo and/or goiter during long-term follow-up. This clarification should help to facilitate appropriate genetic counseling and proper medical management for patients with these mutations, but there was no particular genotype–phenotype correlation among them, suggesting that other factors may contribute to such variability. Objectives. Due to the wide range of phenotypes caused by SLC26A4 mutations, there is controversy with regard to genotype–phenotype correlation. The present study was performed: (1) to determine phenotypic range in patients with biallelic SLC26A4 mutations, and (2) to evaluate whether possible genotype–phenotype correlation exists. Subjects and methods. Phenotypes in 39 hearing loss patients with SLC26A4 mutations were summarized and genotype–phenotype correlation was analyzed. Results. Hearing level varied in the individuals from mild to profound severity. Most of the patients had fluctuating and progressive hearing loss that may have been of prelingual onset. Twenty-four (70.6%) patients had episodes of vertigo, and 10 (27.8%) patients had goiter, which had appeared at age 12 or older. In contrast to such phenotypic variabilities, no apparent correlation was found between these phenotypes and their genotypes.