Shaker Mai Mahmoud, Shalabi Taghreed Abdelmoniem, Amr Khalda Said
Prenatal and Fetal Medicine Department, Human Genetics and Genome Research Division, National Research Centre, 33 El Buhooth St, Dokki, Cairo, Egypt.
Medical Molecular Genetics Department, Human Genetics and Genome Research Division, National Research Centre, 33 El Buhooth St, Dokki, Cairo, Egypt.
J Genet Eng Biotechnol. 2021 Mar 22;19(1):44. doi: 10.1186/s43141-021-00147-w.
DNA methylation is an epigenetic process for modifying transcription factors in various genes. Methylenetetrahydrofolate reductase (MTHFR) stimulates synthesis of methyl radical in the homocysteine cycle and delivers methyl groups needed in DNA methylation. Furthermore, numerous studies have linked gene polymorphisms of this enzyme with a larger risk of recurrent pregnancy loss (RPL), yet scarce information is available concerning the association between epigenetic deviations in this gene and RPL. Hypermethylation at precise DNA sequences can function as biomarkers for a diversity of diseases. We aimed by this study to evaluate the methylation status of the promoter region of MTHFR gene in women with RPL compared to healthy fertile women. It is a case-control study. Hundred RPL patients and hundred healthy fertile women with no history of RPL as controls were recruited. MTHFR C677T was assessed by polymerase chain reaction-restriction fragment length polymorphism (RFLP). Quantitative evaluation of DNA methylation was performed by high-resolution melt analysis by real-time PCR.
The median of percentage of MTHFR promoter methylation in RPL cases was 6.45 [0.74-100] vs. controls was 4.50 [0.60-91.7], P value < 0.001. In the case group, 57 hypermethylated and 43 normo-methylated among RPL patients vs. 40 hypermethylated and 60 normo-methylated among controls, P< 0.005. Frequency of T allele in C677T MTHFR gene among RPL patients was 29% vs. 23% among the control group; C allele vs. T allele: odds ratio (OR) = 1.367 (95% confidence interval (CI) 0.725-2.581).
Findings suggested a significant association between hypermethylation of the MTHFR promoter region in RPL patients compared to healthy fertile women.
DNA甲基化是一种用于修饰各种基因中转录因子的表观遗传过程。亚甲基四氢叶酸还原酶（MTHFR）在同型半胱氨酸循环中刺激甲基自由基的合成，并提供DNA甲基化所需的甲基基团。此外，众多研究已将该酶的基因多态性与复发性流产（RPL）的较高风险联系起来，但关于该基因表观遗传偏差与RPL之间的关联，现有信息却很少。特定DNA序列处的高甲基化可作为多种疾病的生物标志物。我们通过本研究旨在评估与健康可育女性相比，RPL女性中MTHFR基因启动子区域的甲基化状态。这是一项病例对照研究。招募了100例RPL患者和100名无RPL病史的健康可育女性作为对照。通过聚合酶链反应-限制性片段长度多态性（RFLP）评估MTHFR C677T。通过实时PCR的高分辨率熔解分析对DNA甲基化进行定量评估。
RPL病例中MTHFR启动子甲基化百分比的中位数为6.45[0.74 - 100]，而对照组为4.50[0.60 - 91..7]，P值<0.001。在病例组中，RPL患者中有57例高甲基化和43例正常甲基化，而对照组中有40例高甲基化和60例正常甲基化，P<0.005。RPL患者中C677T MTHFR基因的T等位基因频率为29%，而对照组为23%；C等位基因与T等位基因：优势比（OR）=1.367（95%置信区间（CI）0.725 - 2.581）。
研究结果表明，与健康可育女性相比，RPL患者中MTHFR启动子区域的高甲基化之间存在显著关联。
