乌鲁木齐市老年人群中载脂蛋白E基因与阿尔茨海默病发病及风险预测的相关分析

背景载脂蛋白E基因多态性与阿尔茨海默病发病有关,多数学者报告载脂蛋白Eε4等位基因与家族性阿尔茨海默病和散发性阿尔茨海默病有关.目的验证乌鲁木齐市老年人群中散发性阿尔茨海默病与载脂蛋白E基因多态性的关系,并分析载脂蛋白E基因对散发性阿尔茨海默病发病风险的预测价值.设计病例-对照实验.单位解放军兰州军区乌鲁木齐总医院临床医学研究所和神经内科.对象选择2001-01/2003-01解放军兰州军区乌鲁木齐总医院神经内科住院或门诊以及老年公寓筛查阿尔茨海默病患者60例,男28例,女32例;年龄52～91岁,平均(74.2±19.5)岁;受教育时间0～16年,平均4.43年,其中文盲28例,小学13例,初中12例,高中4例,大学3例.选择2002-02/12新疆地区无血缘关系的健康查体人群90例为对照组,男59例,女31例;年龄50～101岁,平均(69.9±25.5)岁;受教育时间0～16年,平均7.96年,其中文盲14例,小学23例,初中25例,高中21例,大学7例.参与者均知情同意.方法抽取5 mL全血,乙二胺四乙酸抗凝后采用苯酚-氯仿法自外周血白细胞中提取基因组DNA.应用聚合酶链反应扩增载脂蛋白E基因第4外显子中含多态性位点的DNA片段,Hha I限制性内切酶切后进行电泳,银染色后分析阿尔茨海默病组和对照组载脂蛋白E各等位基因、基因型的频率.主要观察指标①阿尔茨海默病组和对照组基因型和等位基因频率.②阿尔茨海默病组和对照组不同性别、年龄、受教育程度的载脂蛋白Eε4等位基因频率.结果参加试验阿尔茨海默病患者60例,健康对照组90例,均进入结果分析.①阿尔茨海默病组ε3/ε4,ε4/ε4基因型频率高于对照组(26.67%,11.11%;3.33%,1.11%,P＜0.05).ε2/ε3基因型频率低于对照组(5.00%,14.00%,P＜0.05).②载脂蛋白Eε4等位基因在阿尔茨海默病组中出现的频率高于对照组(17.50%,7.22%,P＜0.05),载脂蛋白Eε2等位基因低于对照组(6.67%,13.33%,P＜0.05).③阿尔茨海默病组女性ε4等位基因频率明显高于对照组(20.97%,5.00%,P＜0.01).④阿尔茨海默病组中≥75岁患者ε4频率低于＜75岁患者(8.57%,30.00%,P＜0.01),而且阿尔茨海默病组＜75岁患者ε4频率明显高于对照组(30.00%,7.02%,P＜0.01).⑤阿尔茨海默病组中文盲和小学程度患者ε4等位基因频率明显高于对照组(10.00%,0.56%,P＜0.001;5.00%,1.12%,P＜0.01).结论①本组结果也验证了载脂蛋白Eε4等位基因与乌鲁木齐散发性阿尔茨海默病有明显相关性,其基因型以ε3/ε4为主.②ε2等位基因在阿尔茨海默病发生时具有一定保护作用.③女性、75岁以下、低教育程度、载脂蛋白Eε4等位基因携带者具有更高的阿尔茨海默病发病风险性.

Relationship between Apolipoprotein E gene and the risk for onset of Alzheimer disease in aged adults in Urumqi

BACKGROUND: Apolipoprotein E (ApoE) gene polymorphism is associated with the onset of Alzheimer disease (AD), most of the researchers reported that ApoE ε4 allele accounts for familial AD as well as for sporadic AD.OBJECTIVE: This study was designed to validate the relationship between ApoE gene polymorphism and the sporadic AD in Aged Adults in Urumqi, and to evaluate the value of ApoE gene for prediction the risk of sporadic AD.DESIGN: Controlled comparative study based on patients.SETTING: It was conducted at the Institute of Clinical Medicine and the Neurological Department of Urumqi General Hospital of Lanzhou Military Area Command of Chinese PLA.PARTICIPANTS: From January 2001 to January 2003, 60 aged inpatients and outpatients at the Neurological Department of Urumqi General Hospital of Lanzhou Military Area Command of Chinese PLA and elderly in the Old People's Home were screened for AD. Of all these participants,28 were males and 32 were females, with an age from 52 to 91, in average of (74.2±19.5) years old, They had 0-16 years education, in average of 4.43 years, 28 were illiterate, 13 were at primary school educational level,12 were at junior middle school educational level, 4 were at high school educational level and 3 were at college educational level. From February to December 2002, 90 genetically unrelated individuals with healthy physical examination findings in Xinjiang area were selected into control group, 59males and 31 females, with an age from 50 to 101 years old, in average of (69.9±25.5) years old, have 0-16 year's education, in average of 7.96years. Of all the controls, 14 were illiterate, 23 were at primary educational level, 25 were at junior middle school educational level, 21 were at high school educational level and 7 were at college educational level. Informed consents were obtained from all the participants.METHODS: 5 Ml blood samples, anticoagulated with ethylene diamine tetraacetic acid (EDTA), were drawn from each participant. Then genome DNA was extracted from peripheral white blood cells using the phenolchloroform method. A fragment containing polymorphism site in exon 4 of ApoE were amplified using the polymerase chain reaction (PCR), were digested with Hha I and were identified using electrophoresis and silver staining. Then, ApoE genotypes and the frequency of ApoE alleles were compared between AD group and control group.MAIN OUTCOME MEASURES: ① ApoE genotypes and the frequency of ApoE alleles were measured in AD group and control group. ② The frequency of ApoE alleles were calculated in participants with different sex,age and educational level in AD group and control group.RESULTS: Sixty patients with AD and 90 healthy individuals participated this investigation. All of them entered the statistical analysis procedure.① The frequency of ε3/ε4 and ε4/ε4 alleles was higher in AD group than in control group (26.67%,11.11%; 3.33%, 1.11%; P ＜ 0.05). The frequency of e2/ε3 in AD group were lower than control group (5.00%,14.00%, P ＜0.05). ② The frequency of ApoE ε4 allele were higher in AD group as compared with control group (17.50%, 7.22%, P ＜ 0.05). The frequency of ApoE ε2 allele were lower in AD group (6.67%, 13.33%, P ＜ 0.05). ③ The frequency of ApoE ε4 allele in females were higher in AD group than in control group (20.97%, 5.00%, P ＜ 0.01). ④ In AD group, patients ≥ 75 years old have a lower frequency of ApoE ε4 allele compared to those less than 75 years (8.57%, 30.00%, P ＜ 0.01). And in individuals less than 75 years old, the frequency of ApoE ε4 allele were higher in AD group than that in control group (30.00%, 7.02%, P ＜ 0.01). ⑤ In illiterate persons and the individuals with only primary school educational level, the frequency of ApoE ε4 allele were higher in AD group than that in control group (10.00%, 0.56%, P ＜ 0.001; 5.00%,1.12%, P ＜ 0.01).CONCLUSION: ① It is proved that ApoE ε4 allele is significantly associated with sporadicAD in Urumqi and ε3/ε4 is the major genotype. ② ApoE ε2 allele has a protective effect on onset of AD. ③ Those individuals，female,less than 75,lower educational level or carrying ApoE ε4 allele take a higher risk of AD.