[Analysis of 59 cases of large vestibular aqueduct syndrome SLC26A4gene mutation frequency and new mutation sites]

Objective:To study the frequency of SLC26A4 gene mutation sites in children with enlarged vestibular aqueduct deafness in Yunnan, report the new mutation sites of SLC26A4 gene, further clarify the mutation spectrum of SLC26A4gene, and explore the association between biallelic and monoallelic mutations of SLC26A4 gene and CT phenotype of inner ear, so as to provide basis for clinical and genetic diagnosis of deafness. Methods:Review the results of temporal bone CT examination of 390 children after cochlear implantation in the Department of Otolaryngology, Kunming Children's Hospital from August 2016 to September 2021. Sanger sequencing of SLC26A4 gene was performed in 59 children with enlarged vestibular aqueduct. According to the genetic test results, the children who underwent temporal bone CT examination were divided into two groups: SLC26A4 biallelic mutation group（homozygous mutation and compound heterozygous mutation）, monoallelic mutation group, and the association with inner ear CT phenotype was analyzed, and the new sites were summarized and analyzed. Results:The c.919-2a>g mutation was the most common mutation in children with enlarged vestibular aqueduct with SLC26A4 gene mutation. Three new variants of SLC26A4 gene were found; CT examination combined with genetic testing found that a part of children with enlarged vestibular aqueduct was associated with SLC26A4 monoallelic mutation or no SLC26A4 gene mutation was detected. Further research is needed to investigate the involvement of other pathogenic factors in the pathogenesis of EVA.