中文摘要：

目的 研究3例早发性阿尔茨海默病（EOAD）患者的临床表型和基因突变类型.方法 收集3例于郑州大学第一附属医院神经内科就诊的EOAD患者,从外周静脉血提取基因组DNA,应用聚合酶链反应联合Sanger测序对EOAD患者的常见基因进行筛查,包括早老素1（PSEN1）基因、早老素2 （PSEN2）基因、淀粉样前体蛋白（APP）基因第16、17号外显子.结果 3例EOAD患者基因检测均为PSEN1基因7号外显子突变.第1例为家族性EOAD,基因突变类型为PSEN1基因7号外显子相邻2个位点基因突变,且与该家系共分离,其中1个位点为同义突变,另1个位点为新发突变类型Y256N;第2例也为家族性EOAD,基因突变为PSEN1基因新发突变类型H214R;第3例为1例极早发EOAD患者,无家族史,突变类型为PSEN1基因突变G206V.结论 PSEN1基因是EOAD患者的重要致病基因.我们发现了PSEN1基因的2个新发突变和1个已知突变,进一步丰富了EOAD的突变数据库.

英文摘要：

Objective To explore the clinical phenotypes and gene mutations of 3 patients with early onset Alzheimer＇s disease （EOAD）.Methods Three patients with EOAD who were diagnosed in the First Affiliated Hospital of Zhengzhou University were enrolled in the study.We extracted the genomic DNA from peripheral venous blood,and screened the common pathogenetic gene mutations of EOAD with polymerase chain reaction combined with Sanger sequencing,including presenilin 1 （PSEN1） gene,presenilin-2 （PSEN2） gene,the exons 16,17 of amyloid precursor protein （APP） gene.Results The gene mutations of 3 cases all existed on the exon 7 of PSEN1.The first case was familial EOAD with PSEN1 gene mutation for two adjacent loci co-segregated in the family,while one was synonymous mutation and the other was novo mutation type Y256N.The second case was also familial EOAD with PSEN1 novo mutation type H214R.The third case was very early onset Alzheimer＇s disease without family history and presented with a known mutation type G206V.Conclusions PSEN1 gene mutation is common in EOAD patients.In this study,two novo mutations and one known mutation of PSEN1 gene were certified,which enrich the known EOAD mutation types.