The Genetic Testing Center for Deafness in PLA General Hospital is the first specialized genetic testing institution for deafness in China. The Center has completed a nationwide molecular epidemiological investigation of deafness, and set up the largest gene resource bank containing more than 6530 DNA samples of deaf probands and families. The Center first reported that the GJB2 235delC mutation, which is carried by 16.9% of patients in the bank, is the most common mutation in the Chinese deaf population, and the Enlarged Vestibular Aqueduct Syndrome (EVAS) related to the SLC26A4 mutation is the second most common hereditary hearing loss. Moreover, the Center demonstrated that the mitochondrial DNA A1555G and C1494T mutations, which are closely correlated with aminoglycoside antibiotic-induced deafness (AAID), account for 4.4% of cases in the Chinese deaf population. By screening for hotspot mutations in common deafness-related genes, 33% of the deaf population were found to carry pathogenic mutations. The results of the epidemiological investigation not only demonstrated the proportions of different common genes accounting for deafness in the Chinese population, but also provided important data for further research regarding the etiology, prevention, diagnostic methods, and therapy of hereditary deafness.

 The research group at the Center has performed intensive basic study of pathogenic genes of hereditary deafness and revealed the mutation spectrum, pathogenesis, and occurrence of common deaf genes, such as GJB2 and SLC26A4. The Center first found and reported the dominant inheritance patterns of GJB2 and syndromic deafness caused by GJB2 mutations among Asian people. Judging from the relationship between genotype and phenotype, the Center first presented the postulate that SLC26A4 mutation is the most important factor leading to EVAS in Chinese people, which is different from the western hypothesis, and set up a new diagnostic method for EVAS by genetic testing prior to image testing. The impact of mtDNA mutations and haplotype on phenotype and pathological mechanism of in vivo mtDNA mutations in presbycusis are also studied.

Based on the studies of the pathological mechanism and methodology in prevention and invention of hereditary deafness, the Center first presented the scientific precaution mode of AAID in China and proposed a prevention strategy involving the early screening for the mtDNA A1555G mutation. The Center was the first to carry out work regarding prenatal diagnosis in hereditary deafness families in China. Since 2005, 90 deaf families, whose deaf child was confirmed to have hereditary deafness caused by GJB2 and SLC26A4 mutations, have undergone prenatal genetic diagnosis as early as the 10th week of pregnancy, which can avoid another deaf birth in these families. Large-scale prevention and invention strategies established a theoretical basis for the clinical application and promotion of genetic testing for deafness in China.