原发性免疫缺陷双（多）基因致病探索及致病机制分析

Primary immunodeficiency diseases (PID) comprise a group of inherited immune system diseases that predispose affected individuals to an increased frequency and severity of infections, immune dysregulation, autoimmune manifestations and malignancy. Early and precise molecular diagnosis is important not only to take prompt treatment and improve survival for severe PID patients but also provide guidance of vaccines insertion for all PID patients. High throughput sequencing and bioinformatics have revolutionized the discovery of genetic variants underlying PID, however, our earlier findings suggest a majority of patients with different forms of PID from our cohort remain undiagnosed. In order to understand the underlying pathogenetic mechanisms in undiagnosed patients, in particular in newly recognized polygenic forms of PID and diseases caused by a combination of heterozygous mutations in several PID associated genes, we need a broader and more comprehensive analysis approach than what we (and others) have taken to date. Our aims for this project are: 1) reveal genetic variants underlying PID through Next generation sequencing technology; 2) investigate and perform data mining on the published studies and public database, along with the data generated from the prior studies, and employ a new analysis strategy in bioinformatics pipeline, which will facilitate the discovery of PID mutations in digenic/polygenic models; 3)Validate novel mutations functional characterization by using CRISPR/Cas9. The project aims to identify novel genetic variants underlying PID human disease, which will improve our ability to both correctly diagnose our patients and provide a personalized therapy, resulting in an improved quality of life for the patient.

原发性免疫缺陷病(PID)是一类免疫系统功能缺失和缺损导致的遗传疾病，异质性强，表型复杂，患者表现为愈加频繁的感染、免疫失调、自免疫以及恶性肿瘤等。PID早期诊断可挽救重型患儿生命，并予以患者疫苗接种指导。NGS的发展揭示了越来越多的PID致病基础，但仍有大量不同表型的PID患者致病原因不明。为了更好地理解未确诊PID患者的分子致病基础，特别是对于新报道的几个已知PID基因的突变共同作用导致的多基因致病模式，亟待拓展完善现有的研究分析方法。拟通过：1）外显子测序及生物信息分析，结合数据的深度挖掘和分析，揭示新的PID遗传致病变异；2）完善基于测序技术发现PID致病基因的分析流程；3）利用CRISPR/Cas9基因编辑技术进行细胞系水平功能验证，探索PID双（多）基因遗传致病分子机制。本研究将揭示PID新的遗传致病机制，为日后PID精准医疗和个体化医疗提供理论基础，提高患者的生活质量。

原发性免疫缺陷PID（近期被国际免疫学协会联盟IUIS更名为先天性免疫缺陷（Inborn Errors of Immunity，IEI））是一类由基因突变导致免疫器官、细胞或分子缺陷，最终导致机体免疫功能异常的遗传性疾病。理解IEI的致病机制，对其疾病的早期分子诊断及治疗至关重要。虽然目前基于家系单基因水平分析揭示了部分IEI的遗传基础，但大量患者的分子诊断不明，亟需开拓思路，总结已有研究结果，探索其新的致病模式，来加深对IEI遗传机制的理解。.本课题通过对IEI患者开展全外显子组测序研究，发现了包括ITK，ATM，RAG1，DNMT3B和ZBTB24等在内的IEI致病基因及新突变；并探索了IEI双（多）基因遗传模式，发现一些已知IEI致病基因组成的基因对可能共同作用导致部分患者的复杂表型，此外还分析了HLA基因同非MHC区域的免疫相关基因共同作用导致患者疾病表型的可能性；通过整理IEI基因型和表型数据知识库，不仅开发了先天性免疫缺陷致病变异分类器，相关知识也可用于指导新生儿免疫缺陷筛查和新冠重症宿主遗传机制分析；此外还对检测到的致病基因开展免疫组库特征等相关功能分析及机制研究。.本研究鉴定出多个IEI致病基因及新突变，加深了对IEI致病机制的理解，有望提高IEI早期确诊率并为其个体化治疗方案提供理论依据，为后续的IEI临床转化应用和精准医疗奠定基础。