Conotruncal heart defects (CTD) are an important subtype of congenital heart disease that occur due to abnormality in the development of the cardiac outflow tract (OFT). FOXH1 is a transcription factor that participates in the morphogenesis of the right ventricle and OFT. In this study, we confirmed the expression of FOXH1 in mouse and human embryos during OFT development. We also scanned the coding exons and splicing regions of the FOXH1 gene in 605 patients with sporadic CTD and 300 unaffected controls, from which we identified seven heterozygous FOXH1 gene mutations. According to bioinformatics analysis results, they were predicted potentially deleterious at conserved amino acid sites. Western blot was used to show that all the variants decreased the expression of FOXH1 protein, while dual-luciferase reporter assay showed that six of them, with an exception of p.P35R, had enhanced abilities to modulate the expression of MEF2C, which interacts with NKX2.5 and is involved in cardiac growth. The electrophoretic mobility shift assays result showed that two mutations altered DNA-binding abilities of mutant FOXH1 proteins. Phenotype heterogeneity was found in patients with the same mutation. These results indicate that FOXH1 mutations lead to disease-causing functional changes that contribute to the occurrence of CTD.

中文翻译：

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散发性锥周性心脏缺损患者FOXH1突变的鉴定。

空腹性心脏缺陷（CTD）是先天性心脏病的重要亚型，由于心脏流出道（OFT）发育异常而发生。FOXH1是一种转录因子，参与右心室和OFT的形态发生。在这项研究中，我们证实了OFT发育过程中FOXH1在小鼠和人类胚胎中的表达。我们还对605例散发性CTD患者和300例未受影响的对照患者的FOXH1基因的编码外显子和剪接区域进行了扫描，从中我们发现了7个杂合的FOXH1基因突变。根据生物信息学分析结果，预测它们在保守的氨基酸位点可能有害。Western印迹法显示所有变体均降低了FOXH1蛋白的表达，而双萤光素酶报告基因检测表明其中的6个，除p.P35R外，它具有增强调节MEF2C表达的能力，MEF2C与NKX2.5相互作用并参与心脏生长。电泳迁移率变化分析结果表明，两个突变改变了突变体FOXH1蛋白的DNA结合能力。在具有相同突变的患者中发现表型异质性。这些结果表明FOXH1突变导致导致疾病的功能改变，从而导致CTD的发生。