CAJ | 학술논문

背景 Leber遗传性视神经病变(LHON)是由线粒体DNA(mtDNA)遗传的可致盲眼病,了解DNA突变位点对该疾病发生的影响具有重要意义. 目的分析一个Leber遗传性视神经病变家系mtDNA突变与疾病发生之间的关系. 方法收集江西省鹰潭市一个LHON家系中72名母系成员进行系谱分析和突变基因筛选,对其中的11例患者、13例突变基因携带者和49名正常者进行常规眼科检查,按照视力损害的程度分级,视力＞0.3者为正常,0.1 ～0.3者为轻度损害,＜0.05 ～0.1者为中度损害,＜0.02 ～ 0.05者为重度损害,＜0.01者为极重度损害,分析该家系的临床特征.收集受检者周围静脉血2～4 ml进行单个核细胞分离,用改进高盐法提取mtDNA,进行PCR扩增,对突变基因位点进行DNA测序. 结果突变基因的PCR扩增产物DNA测序结果显示72名受检的家系成员中,有24例同时具有G11778A和T14502C两个突变位点,包括11例LHON患者,其余13名为突变基因携带者,但至今尚未发病,故该家系的LHON外显率不足50％,而其他家系成员未检测到G11778A和T14502C突变位点.11例患者的发病年龄为8～ 50岁,平均为24.36岁,显著低于13例基因携带者年龄5～72岁,平均40.38岁,差异有统计学意义(t=2.102,P=0.049). 结论该家系成员的线粒体DNA G11778A和T14502C突变是LHON发病的主要原因,原发性mtDNA突变为LHON发病所必需,但其并非充分条件,一个有效的“二次打击”过程同样具有重要的作用.
배경 Leber유전성시신경병변(LHON)시유선립체DNA(mtDNA)유전적가치맹안병,료해DNA돌변위점대해질병발생적영향구유중요의의. 목적 분석일개Leber유전성시신경병변가계mtDNA돌변여질병발생지간적관계. 방법 수집강서성응담시일개LHON가계중72명모계성원진행계보분석화돌변기인사선,대기중적11례환자、13례돌변기인휴대자화49명정상자진행상규안과검사,안조시력손해적정도분급,시력＞0.3자위정상,0.1 ～0.3자위경도손해,＜0.05 ～0.1자위중도손해,＜0.02 ～ 0.05자위중도손해,＜0.01자위겁중도손해,분석해가계적림상특정.수집수검자주위정맥혈2～4 ml진행단개핵세포분리,용개진고염법제취mtDNA,진행PCR확증,대돌변기인위점진행DNA측서. 결과 돌변기인적PCR확증산물DNA측서결과현시72명수검적가계성원중,유24례동시구유G11778A화T14502C량개돌변위점,포괄11례LHON환자,기여13명위돌변기인휴대자,단지금상미발병,고해가계적LHON외현솔불족50％,이기타가계성원미검측도G11778A화T14502C돌변위점.11례환자적발병년령위8～ 50세,평균위24.36세,현저저우13례기인휴대자년령5～72세,평균40.38세,차이유통계학의의(t=2.102,P=0.049). 결론 해가계성원적선립체DNA G11778A화T14502C돌변시LHON발병적주요원인,원발성mtDNA돌변위LHON발병소필수,단기병비충분조건,일개유효적“이차타격”과정동양구유중요적작용.
Background Leber hereditary optic neuropathy (LHON)is a mitochondrial DNA (mtDNA)hereditary disease,so it is significant to understand the influence of DNA mutation on the occurrence of LHON.Objective This survey was to evaluate the role of mtDNA mutation in the development of LHON.Methods This survey study was approved by the Ethic Committee of Wuhan General Hospital of Guangzhou Military Command and written informed consent was obtained from each subject before the relative medial examination.Seventy-two matrilineal relatives from a family with LHON were collected for a pedigree analysis and mutation screening.Regular eye examination was performed on 11 patients,13 mutant gene carriers and 49 individuals with normal phenotype,and the degree of visual damage was graded as follows: ＞0.3 was normal,0.1-0.3 was mild damage,＜0.05-0.1 was moderate damage,＜0.02-0.05 was severe damage and ＜0.01 was very severe damage.Clinical characteristics of LHON was evaluated.The periphery blood sample of 2-4 ml was collected from individuals to separate the mononuclear cells,and the mtDNA was extracted by modified high salt method.MtDNA was amplified by PCR and the mutation loci was sequenced.Results PCR amplification product sequencing of mutant gene showed that both G11778A and T14502C mutations were detected in 24 of 72 matrilineal relatives,but only 11 of 24 carriers developed LHON.No abnormal clinical findings were seen in the 13 carriers,showing a less 50％ penetrance in this family.There was no G11778A or/and T14502C mutation in the normal phenotype individuals of this family.The onset age for vision impairment in 11 affected matrilineal relatives varied from 8 to 50 years old,with the mean age of 24.36 years old,showing a significantly lower age than that of the 13 carriers (5-72 years old,mean 40.38 years old) (t =2.102,P=0.049).Conclusions This study suggests that the Gl1778A and T14502C mutation in mitochondrial DNA is one of causes in the development of LHON.The primary G11778A mutation together with T14502C mutation in mtDNA is a factor for the occurrence of LHON,hut it is not sufficient to the development of LHON.An effective “second hit” process will play an inducing role for LHON.