Hansen P S, Gerdes L U, Klausen I C, Gregersen N, Faergeman O
Department of Internal Medicine and Cardiology A, Aarhus Amtssygehus University Hospital, Denmark.
Clin Chim Acta. 1994 Jan 31;224(2):131-7. doi: 10.1016/0009-8981(94)90179-1.
Apolipoprotein E (apo E) genotypes have been determined in 460 Danish men, with the use of the polymerase chain reaction (PCR) to amplify a 244 base pair fragment spanning the first-base polymorphic sites in the codons of amino acids 112 and 158 followed by restriction endonuclease cleavage. The results were compared with the apo E phenotypes previously determined by isoelectric focusing (IEF) of delipidated plasma, not pretreated with neuraminidase, followed by apo E specific immunoblotting. Conflicting results were found in only 9 cases (2.0%) and in each case only with respect to one allele. Five of the discrepancies can be explained, post hoc, by technical difficulties with the IEF method ('faint bands'). A possible cause of the other 4 discrepancies is the presence of rare mutations. Our findings in this large study are reassuring, since, if appreciable and systematic misclassification of genotypes do occur by using IEF, as has been reported from some laboratories, it may influence the validity of genetic epidemiological studies.
利用聚合酶链反应（PCR）扩增跨越氨基酸112和158密码子中第一个碱基多态性位点的244个碱基对片段，随后进行限制性内切酶切割，已确定460名丹麦男性的载脂蛋白E（apo E）基因型。将结果与先前通过对未用神经氨酸酶预处理的脱脂血浆进行等电聚焦（IEF），然后进行apo E特异性免疫印迹所确定的apo E表型进行比较。仅在9例（2.0%）中发现了相互矛盾的结果，并且在每种情况下仅涉及一个等位基因。事后分析发现，其中5个差异可以通过IEF方法的技术难题（“模糊条带”）来解释。另外4个差异的一个可能原因是存在罕见突变。我们在这项大型研究中的发现令人放心，因为如果像一些实验室所报告的那样，使用IEF确实会出现明显且系统性的基因型错误分类，那么这可能会影响遗传流行病学研究的有效性。
