肥胖儿童瘦素受体基因外显子3057位G→A突变及其临床意义

Relationship of variation 3057 G→A of exon 20 of leptin receptor gene to lipid metabolism and fat distribution of children with obesity

目的 探讨瘦素受体 ( leptin receptor,L EPR)基因第 2 0外显子变异对脂质代谢的影响。方法用聚合酶链反应 -限制性片段长度多态性分析方法及聚丙烯酰胺凝胶电泳方法分析瘦素受体基因的第 2 0外显子基因变异频率 ,并测定单纯型肥胖儿童及健康儿童的血清中甘油三酯、总胆固醇、高密度脂蛋白、低密度脂蛋白。两组分别测身高、体重 ,按公式计算体重指数 ,脂肪百分比。结果 有 3种第 2 0外显子的基因型 ,其酶切片段分别为 A/A型 :2 0 1bp、75 bp;G/A型 :2 0 1bp、173bp、75 bp;G/G型 :173bp、75 bp。肥胖儿童与健康儿童比较 ,前者瘦素受体基因的第 2 0外显子 30 5 7位 G→ A突变频率增高 ,差异有显著性 ( P<0 .0 5 )。A/A基因型的肥胖儿童其血清甘油三酯浓度、体重指数、脂肪百分比均明显高于 G/G基因型者 ( P<0 .0 1) ,而血清高密度脂蛋白水平则低于后者 ( P<0 .0 1) ,对于 G/A型肥胖儿童来说 ,除其血清甘油三酯浓度高于G/G基因型者外 ( P<0 .0 5 ) ,余各项指标均与另外两种基因型无明显差别。结论 本组单纯型肥胖儿童瘦素受体基因第 2 0外显子存在基因多态性 。

Objective To assess the relationship of the variation of exon 20 of leptin receptor ( LEPR ) gene to the lipid metabolism and fat distribution of the children with obesity. Methods Polymerase chain reaction-restriction fragment length polymorphism(RFLP) and polyacrylamide gel electrophoresis were used to analyze the variation of exon 20 of the LEPR gene of the obesity group(72 obesity children) and the control group(60 healthy children).At the same time, all childrens' serum triglyceride(TG),total cholesterol(TC),high density lipoprotein cholesterol(HDL-C), low density lipoprotein cholesterol(LDL-C), height and weight were measured, and their body mass index(BMI) and fat percent(%fat) were calculated. Results Three genotypes of exon 20 of LEPR gene were detected in this study. Compared with the control, the frequency of gene variation at 3057 nucleotide G→A transversion was higher( P <0.05).The concentration of serum TG and the BMI and %fat of the A/A genotype obesity children were higher than those of the G/G genotype ones( P <0.01),but the level of serum HDL of the A/A children were lower than that of the G/G children( P <0.01). As to the G/A genotype children, only their serum TG level was higher than that of the G/G genotype ones( P <0.05). Conclusion The above findings indicated there were polymorphisms in the children with obesity, and those polymorphisms might remarkably affect their lipid metabolism and fat distribution.