全外显子组测序探寻先天性脊柱侧凸发生发展相关基因的研究

Congenital scoliosis is a severe malformation of spine, most of the patients lose their ability of motion due to spinal malformation or abnormal cardiorespiratory function，therefore, it will not only casue psychophysical problems but also bring high burden to families and society. Because of lacking of early prediction methods, most patients were found in their late phase. Therefore, it is important to detect new diagnostic methods and therapeutic targets. As we know, some diseases are caused by certain gene mutation, and as the coding gene in genome, exons determine the variety and function of proteins. In the early development stage of embryo, some somitic developing related genes mutation in the level of exome may cause the occurrence of CS, and the clinical type and progression of CS may also be determined by these mutations. Our group previously reported SNP of TBX6 gene is releated to the genetic predisposition of CS in Chinese Han population. In this project, whole exome sequencing, a next generation sequencing, will be used with the strategy of PPC family pedigrees combining with sporadic cases，further identification will also be done in another group of cases and normal population sample. Our aim is to find genes related to the onset and development of CS, to provide theoretical foundation of genetic and biomolecular etiology, to explore new clinical/genetics typing, furthermore, to provide practical basis of early diagnosis and treatment of CS.

先天性脊柱侧凸（congenital scoliosis，CS）是一种严重致残性疾病，给家庭和社会造成极大负担。因缺乏早期预测手段，本病多在出现严重脊柱畸形才被发现，因此，探索早期诊断方法和病因治疗靶点是当前CS的研究热点。基因突变可导致疾病的发生，外显子作为基因的表达序列，决定了基因编码的蛋白种类和功能。在胚胎发育时期，某些与体节发育相关的外显子水平的基因突变可能导致CS的发生，而外显子水平的基因突变又可能决定了CS的不同临床表型及进展。本项目前期采用候选基因关联研究的策略，首次发现TBX6基因外显子的改变与CS易感性相关，初步验证了上述假说；下一步将通过核心家系结合散发病例的研究策略，采用二代测序的技术，在全外显子组水平确定与CS发生发展相关的基因，为预测疾病发展和指导临床早期干预时机提供理论依据，探索新的CS临床/遗传学分型，探寻CS的个体化早期诊断和治疗措施。

先天性脊柱侧凸是由于胚胎期脊柱发育异常导致的三维畸形，可导致患者丧失劳动力甚至残疾，给社会和家庭造成严重负担，目前该病的确切病因尚不明确。2015年1月8日，我们团队团队在世界顶级医学刊物《新英格兰医学杂志》(The New England Journal of Medicine，简称NEJM，影响因子55.87)以原创性论著(Original Article)形式，发表了 “TBX6基因无效变异联合常见亚效等位基因导致先天性脊柱侧凸”。该研究采用先进的“比较基因组杂交芯片”技术，在国际上首次解析了先天性脊柱侧凸患者的全基因组拷贝数变异，发现散发先天性脊柱侧凸患者的基因组16p11.2区域内存在大片段的DNA缺失，基因测序分析将缺失区域内的TBX6基因确认为致病基因。在机制探寻中，该研究发现TBX6 基因的缺失、无义、或移码等不同形式的无效变异本身还不足以导致先天性脊柱侧凸，通常需要联合一个常见的TBX6亚效等位基因来共同致病。进一步分析病例的临床特征发现，此类突变所致的脊柱畸形在临床表型上具有高度的一致性，在此篇论著中首次提出了“TBX6相关性先天性脊柱侧凸”(TBX6-associated congenital scoliosis，TACS)这一概念。.　　上述结果不仅揭示了TBX6是迄今最重要的先天性脊柱侧凸致病基因，而且解释了TBX6基因致病的复合遗传机理。该研究发现高达7.5%的先天性脊柱侧凸患者存在16p11.2区域罕见变异(正常人群为3/万)这一独特现象，为揭示其他复杂疾病的病因提供了新的思路，是国际骨关节疾病领域的重大突破。该研究从临床实际需求出发，揭示了先天性脊柱侧凸最重要的致病模式，为先天性脊柱侧凸早期诊断及遗传咨询提供了理论依据。另外，我们也发现了LMX1A多态性与中国汉族人群脊柱侧弯发生的关联。