Background: The clinical characteristics of LVAS have attracted more and more attention, its audiology and imaging features have also been deeply studied.
Objective: To analyze phenotypes, genotypes of EVA, and find out the relationship between them.
Methods: Sixty EVA patients were tested by audiometry, temporal bone high-resolution CT and inner ear MRI. SNPscan technology were carried out after the patients signed informed consent. SPSS19.0 software was used.
Result: 1. Three types malformations include EVA, EVA with Mondini and Mondini were found. They accounted for 48.20%, 40.10%, and 11.70%. 2. The SLC26A4 gene mutation frequency was (47/53) 88.68% in EVA patients. The most common genotype was c.919-2A > G/c.919-2A > G, accounting for 28.30%. The most common mutation type was c.9I9-2A > G. 3. GJB2 and SLC26A4 gene mutation frequencies were significantly different (χ2＝65.185, p<.001).
Conclusions: 1. EVA patients with severe sensorineural hearing loss were always diagnosed in childhood and Cochlear implantation was feasible for these patients with the bilateral hearing loss. 2. SLC26A4 gene was closely related to EVA. 3. GJB2 and mtDNA genes were not responsible for EVA.
Significance: The relationship between genotype and clinical phenotype provides a theoretical basis for future gene diagnosis and prevention and treatment of LVAS.
Keywords: Deafness; GJB2; Mondini malformation; SLC26A4; enlarged vestibular aqueduct; gene; hearing loss; mtDNA.