含1555位点的线粒体DNA拷贝数与非综合征型耳聋临床表型的关系

目的 定量检测非综合征型耳聋患者mtDNA A1555G突变型/野生型的拷贝数,探讨mtDNA A1555G突变型的拷贝数与临床表型之间的关系.方法 建立RT-ARMS-qPCR系统对含突变型和野生型mtDNA 1555位点的拷贝数进行定量检测并计算其突变的比例.结合散发组和家系组耳聋患者的临床资料,分析mtDNA A1555G突变型的拷贝数与耳聋严重程度的关系.结果 散发组mtDNA A1555G同质性突变的患者中,突变拷贝数与耳聋轻重程度无关(R=0.001,P=0.997);散发组mtDNA A1555G异质性突变的患者中,突变型与野生型的拷贝数比例与耳聋轻重程度相关(R=0.771,P=0.003);家系组mtDNA A1555G同质性突变的拷贝数与耳聋轻重程度相关(R=0.341,P=0.022);家系组mtDNA A1555G异质性突变的拷贝数与耳聋轻重程度相关(R=0.85,P=0.015).结论 含mtDNA A1555G点突变的拷贝数与非综合征性耳聋的严重程度密切相关,为揭示非综合征耳聋临床表型多样性奠定了基础.

Correlation between degree of mitochondrial DNA 1555 mutation and clinical phenotype of nonsyndromic hearing loss

Objective To study the correlation between the number of mtDNA (mitochondrial DNA) copies containing mtDNA A1555G mutation site and phenotype and further elucidate the molecular genetic basis of phenotype diversity of nonsyndromic hearing loss. Methods Real time-amplification refractory mutation system-quantitative PCR was employed to detect the number of mtDNA copies in mild type and mutant type of mtDNA 1555. Results In the sporadic group, there was no significant correlation between mtDNA A1555G homogenicity mutation copies and phenotype (R = 0.001, P = 0.997) while significant correlation existed between mtDNA A1555G heteroplasmic mutations and phenotype (R =0.771, P = 0.003). In the familial group there was significant correlation mtDNA 1555 homogenicity mutation copies and phenotype (R = 0.341, P = 0.022) and significant correlation existed between mtDNA 1555 heterogenicity mutation copies and phenotype (R = 0.85, P = 0.015) Conclusion There is significant correlation between the mtDNA A1555G mutation copies and the severity of hearing loss.