Abstract：
Congenital heart disease (CHD) represents the most frequent developmental deformity in human beings and accounts for substantial morbidity and mortality worldwide. Accumulating investigations underscore the strong inherited basis of CHD, and pathogenic variations in >100 genes have been related to CHD. Nevertheless, the heritable defects underpinning CHD remain elusive in most cases, mainly because of the pronounced genetic heterogeneity. In this investigation, a four-generation family with CHD was recruited and clinically investigated. Via whole-exome sequencing and Sanger sequencing assays in selected family members, a heterozygous variation in the SMAD4 gene (coding for a transcription factor essential for cardiovascular morphogenesis), NM_005359.6: c.285T > A; p.(Tyr95*), was identified to be in co-segregation with autosomal-dominant CHD in the entire family. The truncating variation was not observed in 460 unrelated non-CHD volunteers employed as control subjects. Functional exploration by dual-reporter gene analysis demonstrated that Tyr95*-mutant SMAD4 lost transactivation of its two key downstream target genes NKX2.5 and ID2, which were both implicated with CHD. Additionally, the variation nullified the synergistic transcriptional activation between SMAD4 and GATA4, another transcription factor involved in CHD. These data strongly indicate SMAD4 may be associated with CHD and shed more light on the molecular pathogenesis underlying CHD, implying potential implications for antenatal precise prevention and prognostic risk stratification of the patients affected with CHD.
摘要：
先天性心脏病（CHD）是人类最常见的发育畸形，并在全球范围内造成大量发病率和死亡率。不断积累的调查强调了CHD的强大遗传基础，>100个基因的致病变异与冠心病有关。然而，在大多数情况下，支撑CHD的可遗传缺陷仍然难以捉摸，主要是因为明显的遗传异质性。在这次调查中,我们招募了一个4代CHD患者家庭,并对其进行了临床调查.通过全外显子组测序和Sanger测序在选定的家族成员，SMAD4基因的杂合变异（编码心血管形态发生所必需的转录因子），NM_005359.6:c.285T>A；p.(Tyr95*)，在整个家庭中被鉴定为与常染色体显性CHD共分离。在用作对照受试者的460名无关的非CHD志愿者中未观察到截断变化。通过双报告基因分析的功能探索表明，Tyr95*-突变体SMAD4失去了其两个关键下游靶基因NKX2.5和ID2的反式激活，这两个基因都与CHD有关。此外,该变异消除了SMAD4和GATA4之间的协同转录激活，GATA4是另一个参与CHD的转录因子。这些数据强烈表明SMAD4可能与CHD相关，并进一步阐明了CHD的分子发病机制。暗示对冠心病患者的产前精确预防和预后风险分层的潜在影响。
