Effect of GJB2 235delC and 30-35delG genetic polymorphisms on risk of congenital deafness in a Chinese population.

Congenital deafness is a serious and irreversible condition in humans. The GJB2 gene is implicated in the pathogenesis of autosomal recessive nonsyndromic hearing loss. Its 235delC and 30-35delG polymorphisms are reported to be associated with risk of hereditary deafness. However, the effect of the interaction between GJB2 235delC and 30-35delG and environmental factors on congenital deafness has not been described. Therefore, we performed a case-control study to investigate the influence of these polymorphisms on congenital deafness risk, and their interaction with maternal and other environmental factors in the development of this disease. Between March 2014 and May 2015, 118 patients with congenital deafness and 242 healthy controls were enrolled into our study. Compared with the GG genotype, the adjusted odds ratios (ORs) [and 95% confidence intervals (CIs)] for the 235delC GC and CC genotypes were 4.66 (1.77-13.07) and 8.28 (2.06-47.52), respectively. Individuals harboring the GC+CC genotypes were at a greatly increased risk of congenital deafness compared to those with the GG genotype (OR = 5.65, 95%CI = 2.54-13.18). However, no significant relationship was established between the 30-35delG variant and this disease. The 235delC polymorphism exhibited an interaction with use of aminoglycoside antibiotics during pregnancy in conferring susceptibility to congenital deafness (chi-square = 8.76, P = 0.003). In conclusion, our study suggests that the GJB2 235delC polymorphism, but not the 30-35delG variant, contributes to congenital deafness susceptibility in the Chinese population examined, and demonstrates an interaction with consumption of aminoglycoside antibiotics during pregnancy in exerting this effect.