Abstract: Objective To screen the common causative sites responsible for hereditary deafness genes in Shandong and to clarify deafness gene mutation patterns in this region by a molecular epidemiological study, thus to provide a basis for further detection and clinical diagnosis of hereditary deafness. Methods Totally 845 cases of patients with non-syndromic hearing loss and 351 cases of normal hearing people without family history of hearing loss were selected. The targeted mutations were detected by the single-tube two-fluorescent PCR method, and the obtained PCR results were analyzed. Results In 845 hearing-loss patients, the positive rates of 235delC, 299_300delAT, 176_191del16, 35delG, 155delTCTG and 512insAACG in GJB2 gene were 19.1%, 6.7%, 0.9%, 0%, 0%, 0.5%, respectively; the positive rates of 538C>T and 547G>A in GJB3 gene were 0.1% and 0%, respectively; the positive rates of IVS7-2A>G, 2168A>G, 1174A>T and 1229C>T in SLC26A4 gene were 12.9%, 3.8%, 1.4% and 0.7%, respectively; the positive rates of A1555G and C1494T in mtDNA 12S rRNA gene were 3.9% and 0.1%. In normal hearing people, the carrier rates of 235delC, 299_300delAT in GJB2 gene and IVS7-2A>G, 2168A>G in SLC26A4 gene were 1.4%, 0.9%, 1.1% and 0.6%, respectively, while the carrier rates of all the other ten sites were 0%. Conclusion In Shandong province, the common mutation sites for hereditary deafness were as the following: 235delC, 299_300delAT, 176_191del16, 512insAACG in GJB2 gene; IVS7-2A>G, 2168A>G, 1174A>T, 1229C>T in SLC26A4 gene and A1555G in mtDNA 12S rRNA gene. Five of these nine sites, GJB2 gene 235delC, 299_300delAT, SLC26A4 gene IVS7-2A>G, 2168A>G and mtDNA 12S rRNA gene A1555G, showed relatively high frequencies of mutation and could be used as the hotspots in this screening project. This study can therefore be a direction for future screening of hereditary deafness gene mutations in Shandong province.

Key words: Mutation site, Non-syndromic hearing loss, GJB2, Shandong province, SLC26A4, mtDNA