家族性阿尔茨海默病早老素-1基因突变研究

Study on mutation of presenilin-1 gene in familial Alzheimer's disease

目的 探讨早老素 - 1(presenilin- 1,PS- 1)基因的突变在家族性痴呆患者发病机理中的作用。方法 应用聚合酶链反应 -单链构象多态性 (polymerase chain reaction- single strand conformationpolymorphism,PCR- SSCP)和 DNA测序技术检测 2例家族性阿尔茨海默病型痴呆 (familial Alzheimer′sdisease,FAD)患者、5 3例散发性阿尔茨海默病型痴呆 (sporadic Alzheimer′s disease,SAD)患者、6 0例血管性痴呆 (vascular dementia,VD)患者及 90名健康老年人 PS- 1基因第 6外显子。结果 DNA测序在 SSCP泳动异常标本中发现 112 3位点和 130 0位点发生错义突变 ,其中 ,FAD患者 2例均在 130 0位点发生突变 ,SAD组 2例在 112 3位点发生突变、2例在 130 0位点突变 ,VD组 1例在 112 3位点发生突变 ;112 3位点发生 C→G突变 (Cys2 3Trp) ,130 0位点发生 A→C突变 (Asp2 0 0 Ala)。结论 FAD及 SAD患者存在 PS-1基因第 6外显子突变 ,上述两个突变位点均位于早老素蛋白的重要功能区 ,此突变可能为病理性突变。

Objective To explore the role of the mutation of presenilin-1 exon 6 in pathogenesis of Alzheimer's disease(AD) patients. Methods Exon 6 of presenilin-1 was analyzed by use of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA analyzer technique in 2 patients with familial AD, 53 patients with sporadic DA, 60 patients with vascular dementia(VD) and 90 normal controls. Results Mobility shift of SSCP in exon 6 of presenilin-1 was detected in 2 cases with FAD, 4 cases with SDA and 1 case with VD. Two missense mutations were found in the patients by DNA sequence analysis, one mutation was 1123 nt C→G(Cys 23 Trp) and the other was 1300 nt A→C(Asp 200 Ala). Conclusion Mutations in exon 6 of presenilin-1 existed in the patients with FAD and SDA, and the two missense mutations were probably pathological by nature.