Discover and functionally characterize full-penetrance causes of nephrosis/FSGS

描述（由申请人提供）：发现并功能性表征肾病/FSGS的完全可复性原因。慢性肾脏疾病（CKD）是人类健康损失最大的疾病之一，其患病率在过去20年中一直在上升。肾病综合征（NS）的定义是显著的蛋白尿，导致低白蛋白血症和水肿。它构成了儿童和年轻人CKD的第二大常见原因，并根据对标准化类固醇治疗的反应分为“类固醇敏感”（SSNS）和“类固醇耐药”（SRNS）。肾组织学表现为局灶节段性肾小球硬化（FSGS）的SRNS不可避免地导致CKD。FSGS在肾移植中复发的风险为33%，导致CKD复发。由于SRNS的发病机制尚不清楚，因此没有有效的治疗方法。对于SRNS，主要原因（病因学）和疾病机制（发病机制）几十年来一直是一个难题。然而，对NS的全突变单基因病因（例如podocin）的基因鉴定已经将肾小球足细胞鉴定为SRNS的疾病机制会聚的细胞类型。在前一个资助期内，我们定义了基因型-表型相关性，允许SRNS变异的预后分类。更重要的是，通过发现PLCE 1和COQ 6基因的突变，我们通过基因图谱确定了可能适合特定治疗的NS的新的罕见单基因病因。我们现在建立了一种新的全外显子组捕获（WEC）和NextGen重测序方法，将其与先前的纯合性作图（HM）相结合，以减轻WEC方法的弱点。我们在全球范围内的67例SRNS/SSNS同胞病例中绘制了隐性NS候选基因座。在这个队列中，最近，我们通过CUBN和ARHGDIA的HM、WEC和MPS突变确定了SRNS的新单基因病因，并且EMP 2突变是SSNS的第一个公认病因。我们还在斑马鱼和小鼠（Coq 6）中建立了疾病模型，我们将用于SRNS单基因病因的治疗研究。因此，我们将追求以下具体目标（SA）：SA 1。通过全外显子组捕获（WEC）和NextGen重测序，利用现有的纯合性作图（HM）数据，在超过67个同胞对中发现肾病的新单基因病因。SA 2.对新发现的SRNS/SSNS的单基因病因进行功能表征，以阐明发病机制。SA 3.对于新发现的SRNS/SSNS基因，研究斑马鱼和小鼠模型中的基因功能和治疗方法，包括Coq 6-/-。

DESCRIPTION (provided by applicant): Discover and functionally characterize full-penetrance causes of nephrosis/FSGS. Chronic kidney diseases (CKD) take one of the highest tolls on human health, and their prevalence has been rising in the last 20 years. Nephrotic syndrome (NS) is defined by significant proteinuria, resulting in hypoalbuminemia and edema. It constitutes the second most frequent cause of CKD in children and young adults and is classified by response to a standardized steroid therapy as "steroid-sensitive" (SSNS) vs. "steroid-resistant" (SRNS). SRNS, with the renal histology of focal segmental glomerulosclerosis (FSGS), inevitably leads to CKD. FSGS carries a 33% risk of relapsing in a kidney transplant, causing recurrence of CKD. Since the pathogenesis of SRNS is unknown, no curative treatment is available. For SRNS, the primary causes (etiology) and disease mechanisms (pathogenesis) have been a conundrum for decades. However, gene identification of full-penetrance single-gene causes of NS (e.g. podocin) has identified the renal glomerular podocyte as the cell type at which disease mechanisms of SRNS converge. Within the previous funding period we defined genotype-phenotype correlations that allow for prognostic classification of SRNS variants. More importantly, by discovering mutations in the genes PLCE1 and COQ6, we identified by genetic mapping novel rare single-gene causes of NS that may be amenable to specific treatment. We now established a new approach of whole exome capture (WEC) and NextGen resequencing, combining it with prior homozygosity mapping (HM) to mitigate the weaknesses of the otherwise powerful WEC approach. We mapped recessive NS candidate loci in a worldwide cohort of 67 sibling cases with SRNS/SSNS. In this cohort, very recently, we identified by HM, WEC and MPS mutation of CUBN and ARHGDIA as novel single-gene causes of SRNS, and mutation of EMP2 as the first recognized cause of SSNS. We also established disease models in zebrafish and mice (for Coq6), which we will use for therapeutic studies on single-gene causes of SRNS. We, therefore will pursue the following specific aims (SAs): SA1. Discover novel single-gene causes of nephrosis by whole exome capture (WEC) and NextGen resequencing in >67 sib pairs with existing homozygosity mapping (HM) data. SA 2. Functionally characterize newly identified single-gene causes of SRNS/SSNS to delineate the pathogenesis. SA 3. For newly identified SRNS/SSNS genes study the gene function and therapeutic approaches in zebrafish and mouse models, including Coq6-/-.