ABSTRACT
Objective To investigate the distribution of-6411A/G (rs208679) polymorphism in the 5' region of catalase (CAT) gene among Han population in Chongqing and its correlation with noiseinduced hearing loss (NIHL).Methods A total of 225 healthy volunteers (normal control group) and 237 noise exposure cases (noise exposure group) were collected from the unrelated Han people in Chongqing.The noise exposure group were further divided into non-deaf group (n =170) and deaf group (n =67) according the presence or absence of NIHL.rs208679 polymorphism in the 5' region of CAT gene was identified using the improved multiplex ligation detection reaction (iMLDR) technique.Genotypes,allelic frequencies and clinical deaf incidence were compared among groups.Results Three genotypes (AA,AG,and GG) were detected in the rs208679 locus.Frequencies of A and G alleles in normal control group and noise exposure group were 0.76 and 0.24 respectively.Genotype distribution in normal control group and noise exposure group showed no deviation from the Hardy-Weinberg equilibrium (P ＞0.05).There were no significant differences in gene polymorphism (AA,AG,and GG) and allelic frequencies (A and G) between normal control group and noise exposure group and between deaf group and non-deaf group (P ＞ 0.05).However,significant difference was observed between deaf group and non-deaf group in recessive analysis (GG vs AG + AA,P ＜ 0.05).Conclusion rs208679 is the predisposing gene to NIHL and can be used as the biomarker for NIHL susceptibility.