GDF1及GDF3介导的Nodal信号通路相关基因的突变与非综合征型先天性心脏病的相关性研究

Non-syndromic congenital heart defect (non-syndromic CHD) is the main type of CHDs and is considered to be polygenic disease.However,the genetic etiology and pathogenic mechanism of non-syndromic CHD remain unclear.It has been showed that the Nodal signaling pathway mediated by GDF1/GDF3 plays a crucial role in the establishment of embryonic left-right asymmetry patterning and the oriented differentiation of cardiac progenitor cells.In our previous experiments,we found that mutations of single gene in this pathway may predispose individuals to non-syndromic CHD. Considering the majority of non-syndromic CHD is a polygenic disease, we therefore postulate that mutations of related genes in the Nodal signaling pathway may have interacting and/or accumulating effects in the pathogenesis of non-syndromic CHDs.In this study,we are going to screen the mutations of related genes in the Nodal signaling pathway with a case-controlled method,then we will investigate the biological function of these mutations.This study will reveal the genetic etiology of non-syndromic CHD and provide the genetic basis of preventing non-syndromic CHD.

非综合征型先天性心脏病（non-syndromic CHD）是CHD的主要类型，目前一般认为绝大多数非综合征型CHD为多基因遗传性疾病，但其确切的遗传学病因与致病机制尚不清楚。研究表明，GDF1及GDF3介导的Nodal信号通路在胚胎左右不对称体轴的建立（包括心脏的不对称发育）及心脏祖细胞的定向分化中发挥重要作用。我们前期的实验初步证实了该通路中单个基因的突变可能增加非综合征型CHD的遗传易感性。鉴于绝大部分非综合征型CHD为多基因遗传性疾病，从整个信号通道出发，我们假设认为，该通道中密切相关的多个基因突变的相互作用或累积效应与非综合征型CHD的发病密切相关。在本课题中，我们采用候选基因和病例-对照策略，对Nodal信号通路中密切相关的基因（GDF1、GDF3和NODAL）进行突变筛查，并进行分子生物学功能分析。课题的实施可望进一步揭示非综合征型CHD的遗传学病因，为疾病的早期预防提供依据。

非综合征型先心病是最常见的先心病类型，其遗传病因还未阐明。我们对200个非综合性型先心病进行突变筛查，识别出Nodal信号通路基因GDF3的一个罕见错义突变（c.G635T, p.S212L），正常对照均不携带该突变。分子细胞实验表明该突变显著促进NODAL基因的表达，提示其具有功能性。针对NODAL基因错义突变（c. T182A, p.L61N）进行功能分析，通过双荧光素酶报告基因发现该突变显著抑制了下游靶基因启动子活性。此外，对Nodal信号通路中多个重要基因进行病例-对照关联分析。我们的研究提示该通路基因突变或变异可能是非综合征型先心病的致病原因。