Investigation of SLC26A4 mutations associated with inner ear malformations

Abstract

To study the molecular pathogenesis of SLC26A4 mutations associated with inner ear malformations including large vestibular aqueduct syndrome (LVAS), Mondini dysplasia and inner ear malformations but not accompanied with LVAS. DNA sample and clinical material were obtained from 14 sporadic LVAS probands, six Mondini dysplasia probands and seven inner ear malformations excluding IVAS probands. SLC26A4 gene mutation was analyzed by direct sequencing for its 20 coding exons. GJB2 gene and also mt12SrRNA were analyzed by direct sequencing. In 14 cases of LVAS, two mutations were detected in 12 patients (85.7%, either homozygous or compound heterozygous mutations), and one mutation was found in two patients (14.3%). In six cases of Mondini dysplasia, two mutations were detected in all of patients (100%). No mutation could be found in the seven cases of other inner ear abnormalities not accompanied with LVAS. No pathogenic mutation was detected in all of these 27 probands in GJB2 gene and mt12SrRNA 1555/1494T. We have shown that LVAS and Mondini dysplasia closely correlate with SLC26A4 gene. No mutation was detected in seven probands of inner ear malformations not accompanied with LVAS. We should study the molecular pathogenesis of this disease in depth.