利用代谢通路分析和外显子测序搜寻中国人群非综合征型唇腭裂的致病基因 

Nonsyndromic oral cleft (NSOC) is a common birth defect in China. Although genome-wide association studies (GWASs) have identified several loci, they account for only a small proportion of the genetic variation of common diseases and the functional variants are still unknown. To address this, based on the previous work of Natural Science Foundation Young Scholar project “Genome-wide association study of nonsyndromic oral cleft using case-parent trio design”(81102178), this project is proposed to identify genetic variants,especially rare and de novo variants, influencing the risk of NSOC among Chinese populations by conducting targeted exon sequencing. The potential biologic pathways with potential causal genes and significant interactions, as well as high-priority candidates identified in previous GWASs will be used to prioritize the target regions for sequencing analysis. A two-stage design will be applied to conduct targeted exon sequencing using 320 Chinese NSOC trios. Family-based SKAT will be implemented for examining the association between rare variants and the disease. Interaction analysis and parent-of-origin effect exploration will also be conducted in the above regions. With these new genotyping technology and new statistical tools, we propose to explore the association of NSOC with various genetic data that may be able to explain the missing heritability from previous GWASs. The proposed study will provide evidence for better understanding the genetic architecture of NSOC, improving disease risk prediction as well as developing individual and population prevention and control strategy in the future.

非综合征型唇腭裂是我国最常见的出生缺陷之一，迄今其致病性遗传位点及发病机制仍不明确，开展病因学研究非常必要。基因定位、揭示发病机制是当前研究的热点和瓶颈。本研究旨在结合家系设计、目标区域外显子测序和通路分析的优势，提高研究效率，搜寻致病性遗传位点。拟募集320个核心家系，在前期工作（国家自然科学基金青年基金项目，81102178）发现的具有显著交互作用的叶酸/同型半胱氨酸代谢通路及WNT信号通路上，结合前期全基因组关联研究（GWAS）发现的阳性位点选取目标区域，采用二阶段设计，对目标区域内编码蛋白质的外显子进行测序，搜寻致病效应强的罕见变异及新发突变，定位致病性遗传变异。同时进行交互作用及亲源效应分析，进一步阐明遗传因素的作用模式。本研究将为后GWAS时代探索罕见遗传变异的作用、明确发病机制提供有益的思路，为未来开展表观遗传学分析、预测疾病风险、制定个体及群体预防措施提供科学证据。

非综合征型唇腭裂（NSOC）是我国最常见的出生缺陷之一，基因定位、揭示发病机制是当前研究的热点和瓶颈。因此本研究基于核心家系，采用二阶段设计，在全外显子区域搜寻非综合征型唇腭裂的潜在罕见致病遗传位点。在前期工作基础上，本课题组在本项基金的支持下已募集病例双亲家系687个。课题组一阶段对24个有阳性家族史的NSOC核心家系开展了全外显子测序，二阶段纳入267个NSOC核心家系进行验证。基于一阶段全外显子测序分析结果，结合课题组前期有重要发现的叶酸/同型半胱氨酸代谢通路、WNT信号通路、HH信号通路和SPRY基因家族，同时结合全基因组关联研究（GWAS）发现的阳性位点选择了18个位点进入二阶段验证。研究结果发现位于SPRY2基因的一个罕见变异和两个常见变异与非综合征型唇裂合并或不合并腭裂（NSCL/P）相关联；位于HH信号通路上PTCH1基因的一个罕见变异，位于WNT10A基因的一个罕见变异与NSOC（包括单纯腭裂）相关联。基因交互作用和亲源效应分析发现了8个位于SPRY2基因的单体型与NSCL/P存在关联，两对SNP之间存在基因-基因交互作用。本研究为后GWAS时代探索罕见遗传变异的作用、明确发病机制提供了有益的思路，为非综合征型唇腭裂的遗传病因探索提供了宝贵的证据，为未来开展表观遗传学分析、预测疾病风险提供了研究基础。