载脂蛋白(a)启动子-418A/G位点和-384C/T位点单核苷酸多态性的研究

目的:研究载脂蛋白(a)启动子区-418位点和-384位点的单核苷酸多态性(SNP),比较种族间单核苷酸的基因型频率分布差异,探讨它们对血脂的影响及同冠状动脉疾病(CHD)的相关性。方法:采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)的分析方法,检测了中国湖北汉族人群无血缘关系的156名健康者及56例CHD患者和65例无血缘关系的非洲贝宁黑种人的Apo(a)启动子-418位点、-384位点单核苷酸的基因型,并对作为酶切底物的PCR产物进行了T-载体法克隆测序。同时,测定血清脂蛋白(a)、总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、ApoAI及ApoB浓度。结果:(1)在对照组中Apo(a)启动子区-418位点只存在等位基因A,未见等位基因G,只有AA基因型,-384位点只存在等位基因C,未见等位基因T,仅有CC基因型;CHD组中,-418位点仅检出1例突变型(GG型),-384位点只有CC型,未发现突变基因T。(2)贝宁黑种人组中,-418位点检出两例突变型(GG型),其他均为AA基因型;-384位点只存在等位基因C,也未发现突变基因T,只有CC基因型。(3)测序结果表明对照人群中Apo(a)基因启动子区(-541--341)序列与GenBank所公布的序列是一致的,并且-418位点碱基为A,-384位点碱基为C。结论:汉族人群中Apo(a)基因启动子区-418位点和-384位点碱基突变率较低,不构成单核苷酸多态性(SNP),与脂质水平及CHD未显示相关性;贝宁黑种人-418位点具有多态性;在种族间的SNP可能存在着较大的差异。

Study on the association of the polymorphism at the position-418A/G and -384C/T in the Apo(a) promoter

AIM: To investigate two single nucleotide polymorphisms (SNP) in the apolipoprotein(a) promoter at positions -418 and -384 and to compare distributing difference of genotype frequencies of single nucleotide among different races and to explore the influencies of them on serum lipid level and their association with coronary heart disease (CHD). METHODS: Using PCR-RFLP (BsgI,BfaI) method, we determined genotypes of these two SNPs in 156 unrelated healthy controls of HanZu Chinese and 56 unrelated CHD patients of HanZu Chinese and 56 unrelated African Blacks, then cloned polymerase chain reaction (PCR) products into T-vector and sequenced it by M13 currency primer, correspondingly. RESULTS: (1) There was no polymorphism at position -418A/A and -384C/C in control group. Only one CHD patient's genotype determined was -418G/G, other were -418A/A and -384C/C in CHD patients. (2) Only two African Blacks' genotype determined was -418G/G, other were -418A/A and -384C/C in African Blacks. (3) However, the Apo(a) promoter sequence was in coincident with the sequence publicized in GenBank and the base at positions -418 was adenine (A) and -384 was cytosine (C). CONCLUSION: The mutation frequencies at position -418 and -384 were low in the Chinese Han Population of Hubei and perhaps no single nucleotide polymorphisms was at two positions. No association with serum lipid levels and CHD was observed. There were great variabilities to the SNPs in the Apo(a) promoter among different races.