携带GJB2基因突变中老年人的听力学特点分析

An Analysis of the Auditory Characteristics of the Middle Aged and Senior Persons with GJB2 Gene Mutation

目的对中老年人进行GJB2基因突变筛查,探讨携带不同GJB2基因突变的中老年人的听力情况。方法收集648例中老年人的听力学资料和血样,提取基因组DNA,经聚合酶链反应(polymerase chain reaction,PCR)扩增GJB2基因编码区,利用直接测序方法获得基因型,并应用统计学分析方法研究携带GJB2基因突变的中老年人在不同听力组间的分布情况及携带不同GJB2基因突变中老年人的听力情况。结果根据听力学资料,将所有中老年人分为四组:正常对照组(A组,157人,24.23%)、轻度听力下降组(B组,199人,30.71%)、中度听力下降组(C组,226人,34.88%)、重度听力下降组(D组,66人,10.19%);通过直接测序的方法,共发现22例分别携带4种移码突变,包括235delC杂合突变(16例,2.78%)、299-300delAT杂合突变(3例,0.46%)、176-191del16杂合突变(1例,0.15%)、512insAACG杂合突变(2例,0.31%);所有突变携带者在不同组间的分布情况为:正常对照组3人(13.64%)、轻度听力下降组6人(27.27%)、中度听力下降组8人(36.36%)、重度听力下降组5人(占22.73%);对四种突变携带者的听力学情况进行分析,176-191del16突变携带者的听力下降程度最轻,而512insAACG突变携带者的听力下降程度最重,经统计学分析,左耳0.25 kHz频率的平均听阈值在各种突变携带者间的差异具有统计学意义(P=0.03)。结论与整体中老年人群相比,携带GJB2基因突变的中老年人在中度听力下降组和重度听力下降组间所占的比例增高;各种突变携带者听力下降程度不同。

Objective To screen the GJB2 gene mutations of the senior people and to investigate the distribution of different hearing levels of GJB2 gene mutation carriers and their hearing threshold levels. Methods The audiological data and peripheral blood of the middle-aged and senior people were collected and genomic DNAs were extracted. Using polymerase chain reaction（PCR）, the code region of GJB2 gene was amplified. All genotypes were detected by direct sequencing. The distribution and hearing threshold levels of the senior people with GJB2 gene mutations were statistically studied. Results According to audiological data,all the middle-aged and senior were divided into four groups., normal hearing group（157 persons, 24.23 % ）, mildly hearing impaired group（199 perspns, 30.71% ）, moderate impairment group（226 persons,34.88%） and severe impairment group（66 persons, 10. 19 % ）. By direct sequencing, we acquired four frame shift mutations, including 235delC heterozygosis mutation（16 persons, 2.78 % ） ,299- 300delAT heterozygosis mutation（3 persons,0.46 % ）, 176- 191dell6 heterozygosis mutation（l person,0. 15%） and 512insAACG heterozygosis mutation（2 persons,0.31%）. The distribution of all mutation carriers among different hearing levels found 3 persons from the normal hearing group（3.64%）, 2 persons from mild group （27.27%）, 8 persons from moderate group（36.36%）and 5 persons from severe group（22.73%）. The analysis of the hearing threshold levels of the four mutation carriers indicated that 176-191dell6 mutation carriers had the least amount of hearing loss while 512insAACG mutation carriers had the worst. Statistical significance was noted among the average hearing thresholds of the mutation carriers at 0.25 kHz in the left ears. Conclusion Out of the whole the middle--aged and senior tested, the proportions of the mutation carriers in moderate and severe impairment groups were noticeably higher while the other mutation carriers demonstrated different degrees of hearing loss.