散发性耳聋GJB2基因突变分析

目的 通过分析内蒙古鄂尔多斯和呼和浩特地区散发性耳聋患者GJB2 235delC点突变，以探讨散发性耳聋患者的分子病因学。方法 对131例(汉族92例，蒙古族39例) 散发性耳聋患者进行耳聋病因学问卷调查、纯音听阈及声导抗测试。聚合酶链反应(polymerase chain reaction PCR)扩增目的片段并用限制性内切酶对其进行GJB2 235delC基因突变检测，对酶切检测结果呈阳性的样本用直接测序法进行验证。对50例健康中国人和100例健康加拿大白种人行限制性内切酶GJB2 235delC点突变检测，作为阴性对照。结果 131例散发性耳聋患者全部为感音神经性聋。在该群体中4例(汉族3例，蒙古族1例)存在GJB2 235delC纯合性突变；3例(汉族2例，蒙古族1例)存在GJB2 235delC杂合性突变。50例健康中国人对照组中检测出1例GJB2 235delC点突变携带者，100例健康加拿大白种人中未检测到GJB2 235delC点突变。结论 GJB2 235delC点突变是中国人散发性感音神经性耳聋的分子病因学之一。内蒙古地区汉族、蒙古族GJB2 235delC突变频率无明显差异，对GJB2 235delC点突变的基因筛查可以明确一些散发性耳聋患者的病因，从而对基因突变引起的散发性耳聋的早期诊断、遗传咨询及防聋治聋起到重要作用。

Mutation analysis of GJB2 in patients with sporadic hearing impairment

Objective To investigate the molecular etiology of sporadic hearing impairment by analyzing 235delC the mutation of the GJB2 in congenital deaf patients in Erdos and Hohhot，Inner Mongolia. Methods The medical histories of 131 patients with sporadic hearing impairment were collected by a questionnaire survey. The audiological examination was conducted with pure-tone audiometry and acoustic admittance measurement. GJB2 235delC mutation was identified by both PCR and restriction enzyme ApaI digestion，then the positive samples were tested with direct sequencing. 50 cases of normal Chinese people and 100 cases of normal Canadian people were used for cross reference. Results 131 patients with sporadic hearing impairment were all diagnosed with sensorineural hearing impairment. 4 cases had homozygous deletion C at position 235 (Han 3 cases，Mongoloid 1 case)and 3 cases (Han 2 cases，Mongoloid 1 case) had heterozygous mutation in 131 patients. One carrier with the GJB2 235delC mutation was found in 50 cases of normal Chinese people，no 235delC mutation in 100 cases of normal Canadian people. Conclusions GJB2 235delC mutation is one of the molecular etiologies in sporadic patients with sensorineural hearing loss. GJB2 235delC allelic frequency between Mongoloid and Han ethnic deaf group in Inner Mongolia does not have great diversity. Screening the mutationsof GJB2 235delC gene can identify pathogenesis in sporadic patients with sensorineural hearing loss, and plays an important part in early diagnosis, genetic counseling, prevention and treatment of deafness in sporadic hearing impairment caused by genetic mutation.