中文摘要：

目的分析线粒体DNA A1555G（mitoehondrial DNA A1555G，mtDNA A1555G）在中国人非综合征型耳聋（NSHI）患者中的突变率及突变性质。方法用PCR．限制性内切酶切分析（-RFLP）和PER产物直接测序法对325例中国人NSHI患者、50名健康体检者的血样进行mtDNA A1555G突变检测及测序分析。结果325例NSHI患者mtDNA A1555G突变率为14．5％（47／325），47例mtDNA A1555G突变中28例为均质性突变，19例为异质性突变；50名健康体检者均未发现同样突变。结论NSHI患者mtDNA A1555G突变率较高，并为均质性和异质性两种突变，这对进一步研究中国人耳聋相关基因突变与临床表型的关系奠定了基础。

英文摘要：

Objective To study the prevalence of the mtDNA A1555G gene mutation in Chinese population with nonsyndromic hearing impairment. Methods PCR-RFLP, directional sequencing of PCR products were applied in 325 patients with nonsyndromic hearing impairment and 50 normal controls. Results The mutation rate of the mtDNA A1555G was 14. 5% （47/325）, 28 of 47 cases were homozygosis, 19 of 47 cases were heterozygosis. The same mutation was not detected in the control subjects. Conclusion The mutation rate of the mtDNA A1555G is relatively high in the Chinese NSHI patients, the mutation type includes both heterozygosis and homozygosis.