目的　研究低密度脂蛋白 (L DL)受体基因外显子 18中 Nco 限制性片段多态性在中国正常人群及血清高胆固醇患者中的频率分布 ,分析基因型与血清高胆固醇之间的相关性。方法　应用多聚酶链反应结合限制性酶切方法 ,对 5 0名健康体检者和 5 0例血清高胆固醇患者进行 L DL受体基因多态性检测。PCR后直接用限制性内切酶酶切检测基因多态性。结果　在正常对照组中 ,A1等位基因的频率为 0 .6 6 ,A2等位基因的频率是 0 .34 ;在血清高胆醇组中 ,A1等位基因出现的频率是 0 .49,A2等位基因的频率是0 .5 1。两组基因频率差异具有显著性 (P<0 .0 5 )。结论　中国南方汉族人群 L DL 受体基因中存在着 Nco 多态性位点 ,Nco 多态性位点与血清高胆固醇相关联 Objective To investigate the frequency distribution of Nco restriction fragment polymorphism in exon 18 of low density lipoprotein receptor (L DL) gene in Chinese normal population and serum hypercholesterolemia, and to analyze the correlation between genotype and serum high cholesterol Sex. Methods Polymerase chain reaction and restriction enzyme digestion were used to detect the polymorphism of L-DL receptor gene in 50 healthy subjects and 50 patients with serum hypercholesterolemia. After PCR, restriction endonuclease digestion was used to detect the gene polymorphism. Results In the normal control group, A1 allele frequency was 0.666, A2 allele frequency was 0.34; in the serum hypercholesterolemic group, A1 allele frequency was 0.49, A2 allele frequency is 0.51. The differences in gene frequency between the two groups were significant (P <0.05). Conclusion There are Nco polymorphisms in L DL receptor gene in southern Chinese Han population, and Nco polymorphism is associated with serum high cholesterol