Genome-Wide Dissection of Mendelian Susceptibility to Mycobacterial Disease

项目摘要 孟德尔人对分枝杆菌病(MSMD)的易感性是一种遗传性和选择性的临床易感性 由弱毒力分枝杆菌引起的疾病，如卡介苗和 环境分支杆菌(EM)。MSMD患者偶尔易受其他巨噬细胞感染 病原体(如沙门氏菌)。MSMD的发病机制一直不清楚，直到1996年，当它的第一个基因 对干扰素-γ受体1(干扰素-γR1)缺乏的儿童的病因进行了破译。过去的遗传学研究 在过去的25年里，已经发现了16个导致MSMD的基因，其中包括14个常染色体(IFNG，IFNGR1，IFNGR2， STAT1、IL12B、IL12RB1、IL12RB2、IL23R、IRF8、SPPL2A、RORC、ISG15、TYK2、JAK1)和2个X连锁基因 (NEMO，CYBB)。这些基因座高度的等位基因异质性定义了31种不同的疾病。的确有 然而，生理上的同质性，因为所有的疾病损害干扰素-γ免疫。5个基因的突变(RORC， ISG15、TYK2、JAK1、STAT1)可作为MSMD的非典型综合征形式的基础，并具有相关的表型。 事后看来，MSMD是一个用词不当的词，因为大多数遗传病因显示MSMD不完全外显。这 偶然发现了真正结核病的遗传病因。值得注意的是，只有大约一半 在我们实验室研究的900名国际患者中，有900人携带MSMD外显子和侧翼内含子的病变。 这16个基因座中的任何一个的区域。在此续订申请中，我们假设未解释的MSMD病例可以 由新的单基因先天性免疫错误所致，可能但不一定涉及干扰素-γ介导 豁免权。我们的目标是通过遵循全基因组(GW)的方法识别新的导致MSMD的基因，基于 主要但不限于全外显子组测序(WES)。我们将招收至少50名MSMD患者 年。我们将通过检验遗传同质性的假说，即搜索，来寻找新的遗传病因 在两个或更多的家庭中发生突变的基因。我们还将测试一个关于遗传异质性的假设，即搜索 因为基因在一个家族中发生了突变。这次搜索将受益于我们长达12年的计算开发 分析WES的工具。将建立候选基因类型与MSMD之间的因果关系 在分子、细胞和免疫学水平上进行了极大的机械深度实验，利用 尖端技术和我们对MSMD长达25年的研究。在没有候选基因型别的患者中 WES，我们将通过整体搜索已知和未知的MSMD致病基因的候选调控变异 基因组测序(WGS)。我们的初步结果令人兴奋，因为我们已经确定了导致MSMD的突变 在已知对干扰素-γ免疫至关重要的基因(Tbx21、irf1)和其他可能破坏干扰素-γ的基因中 新机制的免疫(ZNFX1，MCTS1)。从免疫学的角度来看，这项研究将提供 对人类对分枝杆菌免疫机制的新见解。从医学的角度来看，这项工作 将为MSMD患者提供分子诊断，并为家庭提供遗传咨询，同时提供 治疗性干扰素-γ，至少在其遗传障碍不会消除对干扰素-γ的细胞反应的患者中是这样。

Project Summary Mendelian susceptibility to mycobacterial disease (MSMD) is a genetic and selective predisposition to clinical disease caused by weakly virulent mycobacteria, such as Bacillus Calmette-Guérin (BCG) vaccines and environmental mycobacteria (EM). Patients with MSMD are occasionally vulnerable to other intra-macrophagic pathogens (e.g. salmonella). The pathogenesis of MSMD remained unclear until 1996, when its first genetic etiology was deciphered in children with interferon-γ receptor 1 (IFN-γR1) deficiency. Genetic studies over the last 25 years have identified 16 MSMD-causing genes, including 14 autosomal (IFNG, IFNGR1, IFNGR2, STAT1, IL12B, IL12RB1, IL12RB2, IL23R, IRF8, SPPL2A, RORC, ISG15, TYK2, JAK1) and 2 X-linked genes (NEMO, CYBB). The high level of allelic heterogeneity at these loci has defined 31 distinct disorders. There is however physiological homogeneity, as all disorders impair IFN-γ immunity. Mutations in 5 genes (RORC, ISG15, TYK2, JAK1, STAT1) can underlie an atypical, syndromic form of MSMD, with an associated phenotype. With hindsight, MSMD is a misnomer, as most genetic etiologies show incomplete penetrance for MSMD. This serendipitously led to the discovery of genetic etiologies of bona fide tuberculosis. Remarkably, only about half of the 900 international patients studied in our lab carry MSMD-causing lesions in the exons and flanking intron regions at any of these 16 loci. In this renewal application, we hypothesize that unexplained MSMD cases can result from novel monogenic inborn errors of immunity, possibly but not necessarily involving IFN-γ mediated immunity. We aim to identify new MSMD-causing genes by following a genome-wide (GW) approach, based primarily but not exclusively on whole-exome sequencing (WES). We will enroll at least 50 MSMD patients each year. We will search for novel genetic etiologies by testing a hypothesis of genetic homogeneity, i.e. searching for genes mutated in two or more families. We will also test a hypothesis of genetic heterogeneity, i.e. searching for genes mutated in a single family. This search will benefit from our 12-year-long development of computational tools to analyze WES. Causal relationships between candidate genotypes and MSMD will be established experimentally in great mechanistic depth at the molecular, cellular, and immunological levels, taking advantage of cutting-edge technologies and our 25-year-long study of MSMD. In patients without candidate genotypes by WES, we will search for candidate regulatory variations in known and unknown MSMD-causing genes by whole genome sequencing (WGS). Our preliminary results are exciting, as we have identified MSMD-causing mutations in genes known to be crucial for IFN-γ immunity (TBX21, IRF1) and in other genes that probably disrupt IFN-γ immunity by novel mechanisms (ZNFX1, MCTS1). From an immunological standpoint, this research will provide novel insights into the mechanisms of human immunity to mycobacteria. From a medical standpoint, this work will provide molecular diagnoses for MSMD patients and genetic counseling for families, while offering the use of therapeutic IFN-γ, at least in patients whose genetic disorder does not abolish cellular responses to IFN-γ.