探讨单纯性肥胖儿童脂代谢与LEPR及ApoE基因多态性的相关性。

常规苯酚-氯仿法抽提基因组DNA，用聚合酶链式反应-限制性片断长度多态性(PCR-RFLP)及聚丙烯酰胺凝胶电泳法分析135例单纯性肥胖儿童及84例健康儿童LEPR基因的第20外显子和ApoE基因的第4外显子基因型及等位基因变异频率，并测定两组儿童血清甘油三酯(triglyceride，TG)、总胆固醇(total cholesterol，TC)、高密度脂蛋白胆固醇(high density lipoprotein cholesterol，HDLC)、低密度脂蛋白胆固醇(low density lipoprotein cholesterol，LDLC)浓度，并测定两组儿童身高和体重，按公式计算其体重指数(body mass index，BMI)。

本实验检出3种LEPR基因第20外显子的基因型，分别为:A/A型、A/G型、G/G型；4种ApoE基因第4外显子的基因型，分别为：E3/3型、E4/3型、E2/3型、E4/2型，未检出E2/2、E4/4纯合型。与健康儿童相比，单纯性肥胖儿童LEPR基因第3 057位核苷酸G→A突变频率及ApoE基因第3 934位核苷酸T→C(ε4)突变频率增高(P<0. 05)。与非ε4携带ApoE基因型个体比较，携带ε4基因的G/A型肥胖儿童的血TG，LDLC浓度升高，BMI增高；携带ε4基因的A/A型单纯性肥胖儿童血TC，TG，LDLC浓度升高，BMI亦增高，血HDLC下降，差异有显著意义(P<0.05)。

本地区健康及单纯性肥胖儿童存在LEPR基因第20外显子及ApoE基因第4外显子，存在基因多态性变化。LEPR基因与ApoE基因变异，可以明显影响儿童血脂及BMI，且有一定的协同作用。

To investigate the relationship between the polymorphisms for LEPR,ApoEgene and the lipid metabolism in the children with simple obesity.

Polymerase chain reaction-restriction fragment length polymorphism (RFLP) and polyacrylamide gelelectrophoresis were used to analyze the variation of the LEPR gene and the ApoE gene of the obesity group (135 simple obesity children)and the control group (84 healthy children). At the same time, all children's serum triglyceride(TG), total cholesterol (TC), high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol(LDLC), height and weight were measured, and their body mass index (BMI) were calculated.

In our research, 3 genotypes of LEPR gene (A/A, G/A, G/G) and 4 genotypes of ApoE gene(E3/3, E2/3, E4/3, E4/2) were detected. Compared with control subjects, the A-allele frequencies of LEPR gene and the frequencies of ApoE gene variation at 3 943 nucleotide T → C transversion (e4) in simple obesity children are higher (P<0. 05). In simple obesity children homozygous for the LEPR A-allele, the levels of serum TC, TG,LDLC and BMI of ApoE ε4 allele carriers are higher as well as HDLC being lower than those of e4 non-carrier(P<0. 05). Whereas in heterozygote simple obesity children, the levels of serum TG, LDLC and BMI of ApoE e4-allele carriers are significantly higher than those of ε4 non-carrier (P<0. 05).

There are genotype polymorphisms of LEPR and ApoE genes which may affect the lipid metabolism and BMI in healthy and simple obesity children in our region. The variation frequencies of LEPR A-allele and ApoE e4-allele in simple obesity children are higher than those in healthy children. The LEPR gene coordinating with ApoE gene has effects on lipid metabolisms in children with obesity.