武汉地区85名汉族人群载脂蛋白(a)基因5′侧翼序列多态性及与脂蛋白(a)水平的关系

The Sequence Polymorphism in the Apolipoprotein (a) 5' Flanking Fragment and Its Relation with Lipoprotein (a) Levels in 85 Individuals of Chinese Han Nationality

应用多策酶链反应-单链构家多态性法分析载脂蛋白（a）基因5'侧翼384bp范围内的序列多态性。武汉地区85名健康汉族人群载脂蛋白（a）基因有二种基因型，其频率分别为：基因型I型0．812，基因型Ⅱ型0．188．其中基因型Ⅲ型受检者的脂蛋白（a）均值有升高趋势，但这种差别没有显著性．没有发现此单链构表多态性基因型与血浆脂蛋白（a）浓度间的相关性。

Aim The elevation of the plasma lipoprotein (a) level is an independent genetic risk factor for atherosclerosis and its major manifestations. The wide variation in lipoprotein (a) plasma levels is ex- plained to a large extent by a remarkable size polymor- phism of the apolipoprotein (a ) isoforms and by u- nidentified sequence variation in the apo (a) gene. A search was made for sequence variants in the 5' flank- ing region of the apo (a) gene and its relation with lipoprotein(a) levels in 85 unrelated healthy subjects ' of Chinese Han Nationality.Methods The plasma concentrations of lipoprotein (a) were measured within one week using a sandwich enzyme linked immunosorbent assay. Pairs of 25- base oligonucleotides were used to amplify sequences -59 to +325 of the apo(a) gene from genomic DNA using polymerase chain reaction (PCR). The PCR- omplified DNA fragments were screened for single rand DNA conformation polymorphism (SSCP) using a modification of the method of Orita. Results one single-strand DNA conformation polymorphism in the apo(a) 5' flanking 384 bp frag-ment was reported. The genotype distribution in 85 healthy unrelated subjects were 0. 812 for genotype 1, 0. 188 for genotype Ⅱ. The mean lipoprotein(a) level in the subjects with genotype Ⅱ was higher than that with genotype I, but the difference did not reach statistical significance. The sequence Polymorphism was not associated with the differences in the plasma concentrations of lipoprotein(a).'Conclusions Sequence variants exist in the apolipoprotein (a) 5' flanking fragment in individuals of Chinese Han Nationality. Though no association was found between the SSCP genotyp and the plas- ma concentrations of lipoprotein (a ), the sequence variants reported here may significantly alter gene ex-pression in vitro.