维生素D受体基因多态性与儿童铅易感性的关系

目的　了解某铅污染较重矿区汉族儿童维生素D受体 (VDR)基因多态性的分布状况 ,探讨维生素D受体基因多态性与儿童铅易感性间的关系。方法　整群抽取矿区幼儿园 5～ 6岁汉族儿童 12 0名。研究VDR等位基因 (VDRB和VDRb)的出现频率并测定血铅水平 ,同时问卷调查每位研究对象血铅水平的相关因素。结果　 ( 1)所研究儿童VDRBB型 2例 ,占 1 7% ;VDRBb型 11例 ,占9 2 % ;VDRbb型 10 7例 ,占 89 2 % ;( 2 )携有VDRB等位基因的儿童血铅平均值 [( 0 910 8± 0 2 650 )μmol/L]明显高于VDR基因型为bb者 [( 0 740 1± 0 2 70 1) μmol/L] (t =2 155,P <0 0 5)。 ( 3 )儿童血铅水平相关因素分析发现 :VDR基因型 ,燃料类型及母亲文化程度等 7个因素与血铅显著相关 ,采用多元逐步回归分析后 ,发现VDR基因型对血铅水平的影响在排除协变量影响后仍有显著的统计学意义。结论　本组儿童VDR基因存在遗传多态性 ;携有VDRB等位基因的儿童对铅易感性较高 ,可能成为铅毒性作用的高危人群

Association between vitamin D receptor gene polymorphism and the susceptibility of children to lead

OBJECTS: To investigate the distribution of vitamin D receptor (VDR) genotypes among the Hans of a lead contaminated mine in Shanxi and explore the relationship between blood lead levels and the genetic polymorphism of VDR gene. METHODS: VDR genotypes were determined by polymerase-chain-reaction and restrictive fragment length polymorphism (PCR-RFLP) and the blood lead level was measured by using the graphite furnace atomic absorption spectrometry in a population of 120 pre-school children aged 5 - 6 years who were from the mine kindergarten and were unrelated Hans. An environmental questionnaire in relation to blood lead level was filled for each subject. RESULTS: (1) The gene distribution of the VDR phenotypes in these children was VDRBB, 1.7%; VDRBb, 9.2%; VDRbb, 89.2%. (2) The mean blood lead level of the children who had VDR B allele [(0.910 8 +/- 0.265 0) micromol/L] was significantly higher than that whose VDR genotype was bb [(0.740 1 +/- 0.270 1) micromol/L (mean +/- standard deviation)] (t = 2.155, P < 0.05). (3) Many factors were found to affect the blood lead levels, such as the VDR genotype, the type of fuel, educational level of mothers and so on. After controlling the possible confounding variables by multiple regression, the contribution of the VDR phenotype to the blood lead levels was still statistically significant. CONCLUSION: These results indicated that the frequency distribution of the VDR genotype in these children was apparently different from that in Caucasians who had high frequencies of VDR B. The results also indicated that the individuals carrying the VDR B allele were more susceptible to lead poisoning.