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目的通过对青海省三所聋校非综合征型耳聋(nonsyndromic hearing impairment,NSHI)学生线粒体DNA12SrRNAA1555G突变和GJB2基因突变的调查研究,在分子水平了解青海省非综合征型感音神经性聋发生的病因及其特点。方法采集青海省特殊教育学校、西宁市聋哑学校和乐都县职业教育学校共278例NSHI患者血样,提取基因组DNA,多聚酶链反应扩增线粒体DNA和GJB2基因目的片段,Alw26I限制性内切酶检测A1555G点突变,对酶切阳性病例和全部的GJB2基因的PCR产物进行DNA测序。结果278例感音神经性聋患者中16例(5.76%)存在线粒体DNA12SrRNAA1555G点突变;6例(2.16%)为GJB2235delC纯合突变,21例(7.55%)为GJB2235delC杂合及复合杂合突变,其中235delC是GJB2基因致病突变的主要形式,占88.90%(24/27)。结论线粒体DNA12SrRNA A1555G点突变和GJB2基因突变在青海省耳聋人群中的发生率较高,通过其突变筛查可以有效避免高危人群出现耳聋。
OBJECTIVE: To investigate the mitochondrial 12SrRNAA1555G mutation and GJB2 gene mutation in nonsyndromic hearing impairment (NSHI) students in three deaf schools in Qinghai Province to understand the occurrence of nonsyndromic sensorineural deafness in Qinghai Province Etiology and its characteristics. Methods A total of 278 NSHI patients from Qinghai Special Education School, Xixi Deaf-Mute School and Ledu County Vocational Education School were collected for genomic DNA extraction. The mitochondrial DNA and GJB2 gene fragments were amplified by polymerase chain reaction (PCR), and the Alw26I restriction endonuclease A1555G point mutation was detected and DNA sequencing was performed on the PCR products of the digested positive cases and all GJB2 genes. Results Mitochondrial 12S rRNAA1555G point mutation was found in 16 (5.76%) patients with sensorineural deafness, 6 (2.16%) were homozygous GJB2235delC mutations, 21 (7.55%) were GJB2235delC heterozygous and complex heterozygous mutations, 235delC is the main form of GJB2 gene mutation, accounting for 88.90% (24/27). Conclusions Mitochondrial DNA 12SrRNA A1555G point mutation and GJB2 gene mutation have a high incidence in deafness population in Qinghai Province. Deaf screening can effectively prevent deafness in high-risk population.