非综合征型轴后多指的分子遗传学机制研究

The proposed study aims to screen for pathogenic mutation and gene in PAPA3, a locus related to non-syndromic postaxial polydactyly, by utilizing target sequencing, a combination of target region capture and next-generation sequencing technologies. PAPA3 was determined by our group in a large Chinese non-syndromic postaxial polydactyly pedigree by whole-genome linkage analysis. High GC-content and numerous function-unknown genes are features of PAPA3, which hinder traditional mutation screen for this region. Actually, our group has performed exonic mutation screening, SNP and copy number variation analysis and whole-exome sequencing, but hasn't find pathogenic mutation yet. To contrapose the features of PAPA3 and conquer the difficulties, the proposed study plans to sequence the whole PAPA3 region and find the pathogenic mutation hidden in.The goal can be achieved by combining target region capture with next-generation sequencing technology. Based on the pathogenic gene detected in the pedigree, further mutation screening can be performed in sporadic cases to accumulate more data for further analysis. The pathogenic mechanism of the detected causative gene and its role in limb development network, which may guide future functional analysis, can then be inferred by bioinformatic algorithms. Since common mutation types have been excluded by our previous research, the proposed study is highly likely to detect new gene or new regulator related to limb development, which may of great value in understanding the molecular mechanism of limb development.

本申请计划联用目标区域捕获和高通量测序技术，在非综合征型轴后多指基因座PAPA3中进行突变筛查和致病基因克隆。 PAPA3基因座系本研究组通过对一个中国非综合征型轴后多指家系进行全基因组连锁分析确定。该区域以功能未知基因众多、GC含量高为特点；故用常规方法进行突变筛查困难较大。本研究室已对PAPA3进行过外显子突变筛查、SNP分析和拷贝数分析、全外显子组测序，均未找到致病突变。 针对PAPA3基因座的特点，本研究拟结合基因组捕获技术和高通量测序技术，将其全部测通，找到家系的致病突变。根据家系致病基因还在散发患者中进行进一步的突变筛查，积累突变数据。通过生物信息学对该基因突变的致病机理及其在肢端发育通路中的作用加以分析，为下一步研究提供思路与方向。 鉴于常见基因突变类型已被前期工作排除，本研究极有可能找到与肢端发育相关的新基因或新的基因调控区，将为进一步研究肢端发育的机理提供重要的理论依据。