Diagnostic Value of SLC26A4 Mutation Status in Hereditary Hearing Loss With EVA

Many SLC26A4 mutations have been identified in patients with nonsyndromic enlarged vestibular aqueduct (EVA). However, the roles of SLC26A4 genotypes and phenotypes in hereditary deafness remain unexplained. This study aims to perform a meta-analysis based on the PRISMA statement to evaluate the diagnostic value of SLC26A4 mutant alleles and their correlations with multiethnic hearing phenotypes in EVA patients. The systematic literature search of the PubMed, Wiley Online Library, EMBASE, Web of Science, and Science Direct databases was conducted in English for articles published before July 15, 2015. Two investigators independently reviewed retrieved literature and evaluated eligibility. Discrepancy was resolved by discussion and a third investigator. Quality of included studies was evaluated using Newcastle-Ottawa Quality Assessment Scale. Data were synthesized using random-effect or fixed-effect models. The effect sizes were estimated by measuring odds ratios (ORs) with 95% confidence interval (CI). Twenty-five eligible studies involved 2294 cases with EVA data. A total of 272 SLC26A4 variations were found in deafness with EVA and 26 mutations of SCL26A4 had higher frequency. The overall OR was 646.71 (95% CI: 383.30-1091.15, P = 0.000). A total of 22 mutants were considered statistically significant in all ethnicities (ORs >1, P < 0.05). In particular, 8 mutants were specificity of EVA phenotypes in mutations of SLC26A4 for Asia deafness populations (ORs >1, P < 0.05), 4 mutants for Europe and North America (ORs >1, P < 0.05), and the IVS7-2A>G mutations in SLC26A4 were found to have the highest frequency in deafness individuals with EVA phenotype (62.42%). Moreover, subgroups for studies limited to cases with EVA phenotype, 11 mutants relevant risks (RRs) were P < 0.05, especially for IVS7-2A>G bi-allelic mutants assayed in a deafness population (RR = 0.880, P = 0.000). Diagnostic accuracy of SLC26A4 mutation results also identified the significant association of IVS7-2A>G (AUC = 0.99, 95% CI: 0.97-0.99) and p.H723R (AUC = 0.99, 95% CI: 0.98-1.00) detecting deafness with EVA. To conclude, the IVS7-2A>G and H723R in SLC26A4 present a significant predicting value and discriminatory ability for clinical use on diagnosis of EVA within a deafness population.