携带ND1基因G3635A突变的Leber遗传性视神经病变三家系线粒体基因突变位点检测及其分子遗传致病机制

目的 观察3个ND1基因G3635A突变Leber遗传性视神经病变(LHON)家系线粒体基因组中的突变位点，探讨其分子遗传致病机制。方法 3个家系共88名成员纳入本研究。母系成员53名，非母系成员35名。分别采用标准对数视力表、佳能眼底数码彩色照相、Humphrey视野计、俞自萍色觉图、德国罗兰电生理仪对所有成员行视力、眼底、视野、色觉及视觉诱发电位检查。其中，确诊为LHON 16例，未患LHON 72名。选择135名无血缘关系的中国温州地区正常健康者作为对照组。抽取所有受试者外周静脉血，提取全基因组DNA，检测ND1基因G3635A突变位点。采用扩增产物片段有重叠的24对引物，检测3个家系先证者线粒体单体型分型和基因组突变位点。结果 3个家系先证者及母系成员均发现ND1基因G3635A突变位点，非母系成员和对照组受试者均未发现ND1基因G3635A突变位点。先证者线粒体单体型分型分别为东亚单体型N9a3、D4、R11a。先证者线粒体全基因组检测发现，除ND1基因G3635A突变位点外，D-Loop区存在12个变异位点，RNA编码区存在6个变异位点，多肽编码区存在36个变异位点。结论 3个ND1基因G3635A突变家系先证者及母系成员均存在G3635A突变位点；G3635A突变位点是3个家系的分子遗传致病基础。

ND1 G3635A mutation in the mitochondrial DNA in three Chinese pedigrees of Leber's hereditary optic neuropathy

Objective To screen mitochondrial DNA mutations in 3 Chinese pedigrees with Leber's hereditary optic neuropathy (LHON) carrying the ND1 G3635A mutation. Methods88 members (53maternal relatives and 35 paternal relatives)in 3 pedigrees were enrolled. The ophthalmologic examinations were performed for all members, including visual acuity (standard logarithmic visual acuity charts), fundus photography (Canon fundus camera), visual field (Humphrey Visual Field Analyzer), color vision (Yu zhiping color vision plate), and visual evoked potentials (Roland Consult RETI port gamma, flash VEP).16 members had LHON, 72 members did not have LHON. 135 healthy people from Wenzhou were included as the control group. Genomic DNA was extracted from peripheral blood leukocytes of all subjects. G3635A mutation was screened by PCR-amplification of mitochondrial DNA for all subjects. Mitochondrial haplotypes and other mutations in the entire mitochondrial genome were also determined by PCR using 24pairs of primers for the probands. ResultsAnalysis of mitochondrial DNA (mtDNA) in 3 pedigrees revealed the presence of ND1 G3635A mutation in 3 probands and all maternal relatives, but not in paternal relatives and healthy controls. Proband's haplogroup belong to East Asia group N9a3, D4, and R11a. In addition to the G3635A mutation, probands also had other variants including 12 variants in D-loop region, 6variants in RNA gene, and 36 variants in protein-encoding gene. ConclusionsG3635A mutation was identified in probands and maternal relatives of 3 pedigrees of LHON. It showed that G3635A mutation was the pathogenic molecular basis for those patients.