成骨不全症是以骨质疏松为表型、危害极其严重的最常见单基因遗传性骨病，导致反复骨折、严重骨畸形及活动障碍，我国该病诊治水平落后。本研究构建新型二代捕获测序平台，获得大样本成骨不全患者基因突变信息。检测多种新型特异性生化指标及其编码基因表达水平，采用高分辨外周定量CT仪检测骨密度及骨微结构，获得成骨不全症的表型新信息，深入分析基因突变型与表型的关系。针对致病基因新突变，构建SERPINF1基因c.184G>A突变、IFITM5基因 c.119C>T突变新型小鼠模型，观察小鼠表型，探索成骨不全症发病机制。采用新型CRISPR/Cas9基因编辑技术，准确校正小鼠间充质干细胞SERPINF1基因、IFITM5基因的突变序列，观察基因编辑后干细胞对成骨不全小鼠I型胶原表达及调控的影响，小鼠骨密度、骨强度及骨微结构的变化，评估基因编辑后干细胞的分子靶向治疗作用，建立成骨不全症的治疗新策略。

Osteogenesis imperfecta（OI）is the extremely severe and the most common monogenic heritable bone disease with phenotypes of osteoporosis, reduced bone strength, repeated fractures, severe deformity and dysfunction of bone. The diagnosis and treatment of OI is backward in China. The pathogenesis is unclear, the effective treatment is unavailable. We will construct a new targeted next-generation sequencing (NGS) platform, in order to acquire the gene mutation information in a larger sample of OI patients. We detect the serum levels of new biochemical index, such as pigment epithelium derived factor, transforming growth factor beta and sclerostin, as well as the expression level of their encoding gene in bone. We detect bone mineral density, bone strength and skeletal microstructure parameters using high-resolution peripheral quantitative CT instrument, the concave test and three-point bending test. We deeply analyze the relationship between the gene mutations of OI and new information of phenotype. According to novel mutations of Chinese patients with OI, we will establish two kinds of transgenic mouse model of OI with IFITM5 c.184G>A mutation, and with SERPINF1 c.119C>T mutation. We will investigate the metabolism process of type I collagen and the phenotype of transgenic mouse models of OI. Mouse mesenchymal stem cells (MSCs) will be isolated and cultured. We precisely correct SERPINF1 c.184G>A and IFITM5 c.119C>T mutation of MSCs using the new CRISPR/Cas9 gene editing technique and then induce MSCs differentiating to osteoblasts. The induced MSCs are infused to OI transgenic mice. We evaluate the effects of gene edited MSCs on OI through observing the expression level of type I collagen and its regulating protein, the serum levels of pigment epithelium derived factor, transforming growth factor beta and sclerostin, the changes of bone microstructure, bone mineral density and bone strength. We will improve the diagnosis of OI through the targeted NGS platform, and elucidate the OI pathogenesis using new transgenic mice model, and establish a new treatment strategy through new gene editing technology.