Investigation of common disease mechanisms in nonsyndromic and syndromic PKD

多囊肾病（PKD）是一组与原发性纤毛缺陷相关的疾病， 导致终末期肾病它们可以分为主要涉及肾脏和肝脏的疾病， 非综合征性PKD（NS-PKD），以及涉及其他器官系统的PKD，包括大脑，骨骼和 感觉器官，综合征性PKD（S-PKD）。常染色体隐性遗传性PKD（ARPKD; PKHD 1）是主要的 隐性遗传NS-PKD，而S-PKD是一组多样的，主要是隐性疾病，包括： Meckel [MKS]、Joubert综合征[JBTS]和短肋胸廓发育不良（SRTD），多达80种不同的基因 涉案S-PKD具有显著的遗传复杂性，例如基因TMEM 67与几种 不同的疾病，虽然不同的表型的根本原因还不清楚，等位基因 效果可能很重要。此外，越来越清楚的是，隐性PKHD 1等位基因的杂合子携带者 可具有轻度囊性肾/肝表型，类似于极轻度常染色体显性PKD（ADPKD）。我们有 最近发现，S-PKD基因编码鞭毛内转运蛋白（IFFT 140）， 产生一个完全功能的纤毛，也有一个轻度肾囊肿发展的杂合表型。的 这项补助金的目的是更好地了解与隐性（有时是隐性）遗传相关的遗传复杂性。 显性）PKD，前提是了解基因丢失和减少（基因剂量）的影响， 包括等位基因效应的作用，将提高我们对PKD病因和发病机制的理解。 目的1、对PKD阳性和未知人群进行突变筛查，以确定PKD基因的作用。 “隐性”PKD等位基因的病因为S-PKD和NS-PKD，将利用下一步进行突变筛查 代测序方法。一个PKD队列和一群不知道患有PKD的个体（马约 临床生物样本库; n= 53，220），以确定PKD人群的病因并评价 单个“隐性”PKD等位基因的突变表现为轻度囊性疾病。目标2，开发基于细胞的检测方法， 评估NS-PKD（PKHD 1）和S-PKD（TMEM 67）等位基因，将建立体外系统，以确定 NS-PKD基因、PKHD 1和S-PKD基因中未知重要性变体（VUS）的致病性， TMEM67。将确定这些基因产物的运输、成熟和纤毛定位。目标3， 探讨IFT 140致病等位基因的发病机制，将更好地生成动物模型 了解疾病的发病机理。条件等位基因方法和亚纯等位基因方法都将用于 生成可行的模型并表征肾和肾外表型。目的4，确定睫状体缺损 以及与NS-PKD和S-PKD基因相关的遗传相互作用，将监测纤毛运输， 从NS-PKD和S-PKD模型的细胞组成，并探讨这些基因之间的遗传相互作用。 总的来说，这些研究将提供诊断、预后和机制数据， 为这类毁灭性疾病开发新的治疗方法。

Polycystic kidney diseases (PKD) are a group of disorders associated with defects in primary cilia and often causing end stage kidney disease. They can be divided into disorders mainly involving just kidney and liver, nonsyndromic PKDs (NS-PKDs), and ones involving other organ systems, including the brain, skeleton, and sensory organs, syndromic PKDs (S-PKDs). Autosomal recessive PKD (ARPKD; PKHD1) is the main recessively inherited NS-PKD, whereas S-PKDs are a group of diverse, mainly recessive diseases, including: Meckel [MKS], Joubert syndrome [JBTS]; and short rib thoracic dysplasia (SRTD), with up to 80 different genes involved. S-PKDs have marked genetic complexity, for instance the gene, TMEM67, is associated with several different disorders, and although the underlying reason for the varied phenotypes is not well understood, allelic effects may be important. In addition, it is becoming clear that heterozygous carriers of recessive PKHD1 alleles can have a mild cystic kidney/liver phenotype, similar to very mild autosomal dominant PKD (ADPKD). We have recently found that IFT140, an S-PKD gene encoding an intraflagella transport protein (IFT140) that is required to generate a fully functional cilium, also has a heterozygous phenotype of mild kidney cyst development. The goal of this grant is to better understand the genetic complexity associated with recessive (and sometimes dominant) PKD, with the premise that understanding the effects of gene loss and reduction (gene dosage), including the role of allelic effects, will improve our understanding of the etiology and pathogenesis of PKDs. Aim 1, Mutation screen a PKD positive and PKD unknown population to identify the role of “recessive” PKD alleles to the etiology of S-PKD and NS-PKD, will conduct mutation screening using next generation sequencing methods. A PKD cohort and a population of individuals not known to have PKD (Mayo Clinic Biobank; n=53,220) will be screened to determine the etiology of the PKD population and evaluate the role of single “recessive” PKD alleles to manifest as mild cystic disease. Aim 2, Develop cell-based assays to evaluate NS-PKD (PKHD1) and S-PKD (TMEM67) alleles, will establish in vitro systems to determine the pathogenicity of variants of unknown significance (VUS) in an NS-PKD gene, PKHD1, and an S-PKD gene, TMEM67. Trafficking, maturation, and ciliary localization of products of these genes will be determined. Aim 3, Explore the disease mechanism of IFT140 pathogenic alleles, will generate animal models to better understand disease pathogenesis. Both conditional and hypomorphic allele approaches will be employed to generate viable models and characterize the renal and extrarenal phenotypes. Aim 4, Determine ciliary defects and genetic interactions associated with NS-PKD and S-PKD genes, will monitor ciliary trafficking and composition in cells from NS-PKD and S-PKD models, and explore genetic interactions between these genes. Overall, these studies will provide diagnosis, prognostic and mechanistic data, important steps toward developing novel therapeutics for this group of devastating diseases.