MTHFR基因C677T多态性与Down综合征发生的相关研究

目的研究亚甲基四氢叶酸还原酶(MTHFR)基因C677T多态性与Down综合征关系。方法采用聚合酶链反应—限制性片段长度多态性(PCR-RFLP)法对32例DS患儿母亲,70例未生育DS患儿女性MTHFR的C677T进行基因分析。比较上述各组基因型和等位基因频率分布有无差异。结果MTHFR基因C677T突变型等位基因(T)频率在实验组和对照组中有显著性差异,CC、TT基因型频率分布差异有显著性(P<0.05)。CT基因型比CC基因型生育DS患儿风险高2.84倍,TT基因型比CC基因型生育DS患儿风险高9.26倍。结论MTHFRC677T基因多态性与Down综合征发生相关,TT基因型增加了Down综合征的发生风险,CC基因型是降低Down综合征发生的保护性因素。

Study on the relationship between genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR) C677T and development of Down syndrome

Objective:To explore the relationship between genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR), a central enzyme in folate metabolism that affects DNA methylation and synthesis, and the risk of Down syndrome. Methods: Genomic DNA was isolated from the peripheral lymphocytes of 32 mothers of children with Down syndrome and 70 age matched control subjects. Polymerase chain reaction and restriction fragment length polymorphism were used to examine the polymorphisms of MTHFR genes C677T and the relation between these genotypes and risk of Down syndrome was analyzed. Results: It was obvious difference between experiment and control group in MTHFR gene C677T mutation allele (T) frequency (P<0.05),TT and CC had obvious difference(P<0.05). The individuals with 677CT genotype or 677TT genotype had a 2.84 fold or 9.26 fold increased risk of developing Down syndrome compared with those who had 677CC genotype. Conclusion: MTHFR gene mutation allele is related to Down syndrome, TT gene mutation type increased the risk of Down syndrome and CC type perhaps was a protective factor in decreasing the risk of Down syndrome.