Congenital heart defects (CHDs) are the heart structural malformations present at birth. Septal defects account for 40% of CHD, including atrial, ventricular and atrioventricular septal defects. In Pakistan, the prevalence of CHD is 3.4 in 1000, and a study estimated that 60,000 babies are born with CHD annually. Methylenetetrahydrofolate reductase (MTHFR), a chief enzyme, involved in the folate metabolism. The missense mutation, C677T (rs1801133), exists in MTHFR gene, results in a MTHFR thermolabile variant having low enzymatic activity. The study is aim to identify the MTHFR C677T variant association with septal defects. Samples of 194 CHD patients (age $$\overline{X }\hspace{0.17em}$$ = 5.8 ± 5.1) and 50 normal echo controls (age $$\overline{X }\hspace{0.17em}$$ = 6.0 ± 4.9), confirmed by pediatric consultant, were collected. Extracted DNA, quantified by agarose gel electrophoresis and nanodrop, was screened for SNP by high-resolution melting (HRM). Further, HRM results were confirmed using restriction analysis and sequencing. HRM was simply and precisely genotyped the samples within 3 h at low cost. Genotypic data suggested that heterozygous mutant (CT) was frequent in congenital septal defect patients (0.26) which was higher than controls (0.143), p > 0.05. Mutant (TT) genotype was not found in this study. rs1801133 has lack of significant association with congenital septal defects. The absence of TT genotype in this study suggesting the role of natural selection in targeted population. HRM is an easy, fast and next generation of PCR, which may be used for applied genomics.

中文翻译：

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巴基斯坦卡拉奇的先天性间隔缺损：通过 MTHFR C677T 的高分辨率熔解 (HRM) 分析进行突变筛查的更新

先天性心脏缺陷（CHD）是出生时出现的心脏结构畸形。房间隔缺损占冠心病的40%，包括房间隔缺损、心室间隔缺损和房室间隔缺损。在巴基斯坦，CHD 患病率为千分之 3.4，一项研究估计每年有 60,000 名婴儿出生时患有 CHD。亚甲基四氢叶酸还原酶（MTHFR）是参与叶酸代谢的主要酶。MTHFR 基因中存在错义突变 C677T (rs1801133)，导致 MTHFR 不耐热变体具有低酶活性。该研究的目的是确定 MTHFR C677T 变异与间隔缺损的关联。194 名 CHD 患者样本（年龄 $$\overline{X }\hspace{0.17em}$$ = 5.8 ± 5.1）和 50 名正常回声对照样本（年龄 $$\overline{X }\hspace{0.17em}$$ = 6.0±4.9），经儿科顾问确认，收集。提取的 DNA 通过琼脂糖凝胶电泳和 Nanodrop 进行定量，并通过高分辨率熔解 (HRM) 筛选 SNP。此外，HRM 结果通过限制性分析和测序得到证实。HRM 可以在 3 小时内以低成本简单、精确地对样品进行基因分型。基因型数据表明，先天性房间隔缺损患者中杂合突变体（CT）很常见（0.26），高于对照组（0.143），p > 0.05。本研究中未发现突变（TT）基因型。rs1801133 与先天性房间隔缺损缺乏显着关联。本研究中缺乏 TT 基因型，表明自然选择在目标人群中的作用。HRM 是一种简单、快速的下一代 PCR，可用于应用基因组学。