载脂蛋白E基因型与冠心病和2型糖尿病的易感性研究

目的 探讨载脂蛋白E基因型与冠心病(CHD)和2型糖尿病(T2DM)的易感性.方法 应用PCR-限制性片段长度多态性(PCR-RFLP)法、多重特异性扩增突变系统(multi-ARMS)快速分型法和PCR-单链构象多态性(PCR-SSCP)法,对238例CHD、316例T2DM、1 892名健康对照的apoE基因第4外显子112位Cys/Arg和158位Arg/Cys进行检测;随机抽取前2种方法分型标本进行DNA测序法验证,并对所有异常带型标本进行DNA测序,确认是否存在基因变异;同时测定空腹血糖和血浆脂质水平.结果 CHD组血浆HDL-C(t=2.66)和apoA I(t=2.30)水平显著低于健康对照组(P＜0.05),收缩压(t=8.48)、舒张压(t=5.66)、TG(t=3.38)、LDL-C(t=2.48)、apoB(t=1.67)、Lp(a)(t=4.16)和FBG(t=7.04)水平均显著高于健康对照组(P＜0.05),TC水平在两组间差异无统计学意义(t=0.94,P＞0.05);T2DM组收缩压(t=5.74)、舒张压(t=3.35)、血浆TG(t=4.56)、TC(t=5.22)、LDL-C(t:7.00)、apoB(t=2.24)、Lp(a)(t=4.15)和FBG(t=16.93)水平亦均显著高于健康对照组(P＜0.05),HDL-C(t=0.74)和apoA I(t=0.41)水平在两组问差异无统计学意义(P＞0.05).ε2/2、ε2/3、ε3/3、ε4/2、ε4/3、ε4/4基因型在3组中的频率分布为:0.4%,13.4%,58.0%,1.3%,26.5%,0.4%(CHD组);0.6%,5.7%,72.8%,1.9%,14.9%,4.1%(T2DM);0.5%,10.5%,69.6%,1.6%,16.8%,1.1%(健康对照组).CHD组和T2DM组基因型频率分布与健康对照组差异均有统计学意义(χ2:14.90,P=0.00;χ2=7.08,P=0.03),CHD组ε3/4基因型频率明显高于健康对照组(26.5%对16.8%),而ε3/3基因型频率显著低于健康对照组(58.0%对69.6%);T2DM组ε4/4基因型频率明显高于健康对照组(4.1%对1.1%),并首次在国内报道T2DM患者apoE基因第4外显子Arg 150 His突变2例,而在CHD组和健康对照组均未检出.结论 apoE ε3/4基因型频率与CHD有一定的关联;apoE ε4/4基因型频率与T2DM存在一定的关联;血压和部分血脂等指标可作为诊断CHD和T2DM参考指标.

The association of apolipoprotein E genotype with coronary heart disease and type 2 diabetes mellitus

Objective To study on the association of apolipoprotein E(apoE)genotype with coronary heart disease(CHD)and type 2 diabetes mellitus(T2DM).Methods PCR-RFL,multiplex amplification refractory mutation system(muli-ARMS)and PCR-SSCP methods were used to detect the genotype of apoE,and DNA sequencing technique were used for further confrm the genotype and gene variations in 2 446 Chinese individuals,including 238 cases of CHD,316 cases of T2DM and 1 892 healthy controls.Fasting blood glucose(FBG)and plasma lipids levels[TC,TG,HDL-C,LDL-C,apoA I,apoB and Lo(a)]were measured by usual methods.Results Compared with the controls,plasma HDL-C(t=2.66)and apoA I(t=2.30)levels in the CHD group were significantly lower(P<0.05),but not in T2DM group;plasma TC level(t=5.22)in the T2DM group were significantly higher(P<0.05),but not in CHD group;systolic pressure(t=8.48,5.74)diastolic pressure(t=5.66,3.35),plasma TG(t=3.38, 4.56),LDL-C(t=2.48,7.00),apoB(t=1.67,2.24),Lp(a)(t=4.16,4.15)and FBG(t=7.04, 16.93)levels were significantly higher in both CHD group and T2DM group(P<0.05).The distributions of apoE ε2/2,ε2/3,ε3/3,ε2/4,ε3/4 and ε4/4 respectively were 0.4%,13.4%,58.0%,1.3%, 26.5%,0.4% in the CHD group;0.6%,5.7%,72.8%,1.9%,14.9%,4.1% in the T2DM group; 0.5%,10.5%,69.6%,1.6%,16.8%,1.1% in the control group.Significant differences were found between the CHD group(χ2=14.90,P=0.00),T2DM group(χ2=7.08,P=0.03)and the control group for the frequencies of apoE genotype.The distribution of ε3/4 was higher(26.5% vs 16.8%)and ε3/3 Was lower(58.0% vs 69.6%)in the CHD group.In the T2DM group.the distribution of εε4/4 Was higher (4.1% vs 1.1%),and 2 cases of ε3/3 with Arg 150 His mutation in exon 4 of apoE gene were firstly reposed in China,which is none in the CHD and control groups.Conclusions The results suggested that apoE ε3/4 and ε4 genotypes might be associated with the susceptibility of CHD and T2DM.respectively. To some extent,apoE ε3/3 may not be a good genotype for T2DM because of the Arg 150 His mutation. Blood pressure and plasma lipids could be used for diagnosis of the two diseases.