Objective: To analyze the correlation between GJB2 mutations and congenital malformations of inner ear in pediatric patients with sensorineural hearing loss (SNHL).
Method: Peripheral blood samples were collected from 77 pediatric patients with congenital malformations of inner ear. Two control groups were set up, which were control group 1 that contained 80 pediatric patients with congenital SNHL without inner ear malformations, and control group 2 that contained 100 cases with normal hearing, retrospectively. Genomic DNA was extracted from the blood; direct sequencing was used to detect GJB2 mutations.
Result: GJB2 was normal in 31 patients. GJB2 mutations were detected in 12 patients while the polymorphism of GJB2 was present in 34 patients. The homozygous mutations of 235delC was in 1 patient, the heterozygous carriers of 235delC in 4 patients, the heterozygous carriers of p. V37I in 7 patients in which the heterozygous carriers of p. R184Q with autosomal dominant hereditary in 1 patients. In control group 1, normal GJB2 was detected in 17 patients, GJB2 mutation in 29 patients, polymorphism in 34 patients. In control group 2, normal GJB2 was detected in 18 patients, GJB2 mutation in 12 patients, polymorphism in 70 patients. When the distribution of GJB2 genotypes was compared with phenotypes, significant difference was found (P < 0.01) between inner ear malformations and control group 1, but was not (P > 0.05) between inner ear malformations and control group 2.
Conclusion: GJB2 Mutations are not correlated with congenital inner ear malformations. However, GJB2 Mutations are correlated with congenital SNHL that is not caused by congenital malformations of inner ear.