[The analysis of mutations in non-syndromic deafness gene SLC26A4 by next generation sequencing technology]

Objective:To analogize the distribution of nonsyndromic deafness gene SLC26A4 mutation and to characterize clinical profiles in patients with SLC26A4 mutation in order to understand their hereditary etiologies and provide evidence for deafness screening and accurate genetic counseling. Method: SLC26A4 gene was first analized by MALDI-TOF-MS technology to detect the hot mutation c.919-2A>G in 57 cases. There were 3 cases with homozygous mutation and 7cases with heterozygous mutation. Then 54 cases except for 3 cases with homozygous mutation were analyzed by targeted genomic capturing and next generation sequencing technologies(targeted DNA-Hiseq), 81 non-syndromic deafness genes and the chondiogene was designed to all their exons and their flanking intron(±10 bp) sequences. Sanger sequencing was used to confirm the variant by analyzing the DNAs sequences. Result: The carrying rates of SLC26A4 gene in the deafness were 26.32%, but SLC26A4 homozygous genes and compound heterozygous genes were 19.30%. They included 3 cases with c.919-2A>G and 1 case with c.754T>C pathogenic homozygous mutations. While in 7 cases with compound heterozygous there were 6 cases with two pathogenic mutation, there was 1 case with c.2168A>G pathogenic mutation the other likely pathogenic mutation c.1545-1546insC. The 11 cases all were diagnosed large vestibular aqueduct syndrome(LVAS). There were 4 cases with heterozygous that were not found large vestibular aqueduct. Conclusion: Pathogenic mutation of SLC26A4 is closely related to clinical phenotype of LVAS. The hot pathogenic mutation was c.919-2A>G of SLC26A4 gene. The next generation sequencing technology is available for the diagnosis of inherited hearing loss especially for LVAS.