含FRG1基因突变体的先天性马蹄内翻足疾病iPS细胞模型的建立及发病机制的初步探讨

先天性马蹄内翻足（CCF）遗传方式及临床表现的多样性表明多种基因通过不同分子机制引发CCF。目前除PITX1基因外，未明确其他基因突变与CCF发病有关。本课题组前期工作中，发现CCF-Xi'an家系具有CCF患病少见的隐性遗传方式，外显子测序发现，复合性杂合FRG1基因点突变是其致病原因，但FRG1基因突变如何引发CCF的发生，尤其是细胞和分子机制均不清楚。本课题拟利用CCF-xi'an家系成员尿液中脱落细胞，慢病毒四因子转染制备疾病特异CCF－iPSCs和对照iPSCs，诱导它们向不同靶细胞系分化，观察分化后细胞表型的异同，明确引发CCF致病的细胞机制；并通过对FRG1-CUX1相互作用及细胞表达谱的分析，明确此复合性杂合FRG1点突变引发CCF发生的分子机制。通过捕获缺陷细胞并探求其细胞功能障碍，有助于增加对该疾病病理的理解，对CCF病因学的理解具有理论意义。

The diversities of inheritance pattern and clinical manifestation of congenital clubfoot (CCF) indicated a few genes might be involved in the pathogenesis of CCF through different mechanisms. Up to now, there is no other gene defined to be CCF-causing gene besides of PITX1 gene. Our prelimenary data showed that a CCF-Xi'an family is recessive inheritance which is rare in the pathogenesis of CCF. Furthermore, the exome sequencing result indicated that compound heterozygous FRG1 mutation is disease-causing mutation. However, it remains unclear that how compound heterozygous FRG1 mutation leads to CCF and the underlying mechanism is still unknown. This study plans to reprogram cells from urine samples by inducing 4 factors to generate CCF-iPSCs and control iPSCs. When these iPS cell lines are induced to different cell lineages, we will compare and analyze cell phenotype and find the disease-causing cell origin. Furthermore, we will detect and clarify the molecular mechanism leading to CCF by analyzing the interaction between FRG1 and CUX1 and mRNA expression profile. Capturing deficient cells and studying these dysfunctional cells will enrich our understanding on CCF and it will have a theoretic significance to exploring the pathogenesis of CCF.