Modifiers of Retinal Phenotypes in Ciliopathies

纤毛病视网膜表型的修饰因素

• 批准号: 8527788
• 负责人: Erica Ellen Davis
• 金额: $ 36.81万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8527788
• 关键词: Adult; Affect; Alleles; Animals; Architecture; Biogenesis; Biological Assay; Blindness; Cilia; Clinical; Collection; Computer Simulation; Cystic Kidney Diseases; DNA Resequencing; Data; Databases; Defect; Development; Diagnosis; Disease; Dissection; Electroretinography; Engineering; Frequencies; Functional disorder; Genes; Genetic; Genetic Epistasis; Genotype; Guanosine Triphosphate Phosphohydrolases; Hereditary Disease; Human; Human Genetics; In Vitro; Individual; Joubert syndrome; Knock-in Mouse; Lead; Leber' s amaurosis; Lesion; Link; Medical; Modeling; Modification; Mus; Mutate; Mutation; Nature; Neonatal; Organelles; Patients; Penetrance; Phenotype; Photoreceptors; Play; Population; Proteins; Proteome; Reporter; Retina; Retinal; Retinal Degeneration; Retinitis Pigmentosa; Role; Sensitivity and Specificity; Severities; Signal Transduction; Site; Structure; Syndrome; System; Testing; Therapeutic; Variant; base; ciliopathy; cohort; early onset; empowered; improved; in vitro Assay; in vivo; interdisciplinary approach; mouse model; mutant; novel; outcome forecast; photoreceptor degeneration; pleiotropism; protein transport; tool

Genetic lesions affecting ciliary structure and function give rise to a broad collection of genetically heterogeneous and clinically overlapping disorders, known collectively as the ciliopathies, which are characterized by both phenotypic overlap and variable penetrance and expressivity. In the retina, a modified cilium plays an integral role in protein transport across the photoreceptor and is critical for retinal architecture and function, as evidenced by the fact that progressive photoreceptor degeneration is a hallmark of numerous ciliopathies. Accumulating evidence suggests that genes mutated in some ciliopathies can contribute both causal and modifying alleles across the ciliopathy spectrum, giving rise to the idea that both cis and trans acting alleles can contribute to the mutational load of ciliopathy patients and offer the possibility that understanding the genetic architecture of ciliopathies might inform the mechanisms that underlie phenotypic variability in human genetic disorders. To explore this notion, we have previously conducted unbiased medical resequencing of genes known/expected to be important to ciliary biogenesis and function in a large, clinically diverse cohort of patients that span the spectrum of severity. In RPGRIP1L, a gene known to cause neonatal lethal Meckel-Gruber Syndrome (MKS) and moderately severe Joubert Syndrome (JBTS), we identified a highly-conserved A229T change which was present at intermediate population frequency, and was significantly enriched in patients with retinal degeneration. Using an interdisciplinary approach, we went on to show that the Thr229 allele is a non-neutral change that disrupts the direct interaction between RPGRIP1L and RPGR, the most frequent genetic cause of X-linked Retinitis Pigmentosa (XLRP). These data offer us the opportunity explore the genetic mechanism(s) of second-site modification in retinal phenotypes in ciliopathies, and to develop models that can be used to probe such phenomena further. We propose two aims. First, motivated by the opportunity to develop a robust model to study epistasis, we will model the A229T change by introducing it into a mouse model and subsequently crossing the Thr229 allele into lines with sensitized ciliary function to determine if this allele will either induce or exacerbate retinal phenotypes. Second, because our preliminary data suggest that RPGRIP1L might also contribute epistatic alleles to non-syndromic retinal degeneration, we will expand the mutational analysis of RPGRIP1L to an extended cohort of non-syndromic patients and matched controls. Using our previously established in vivo complementation strategy, we will then test the pathogenic potential of newly discovered alleles, and, empowered with functional data, we will determine the overall enrichment of RPGRIP1L alleles in retinal degeneration. The completion of our studies will identify candidate modifier alleles in patients with retinal degeneration, generate new models to study such phenomena and has the potential to inform the genetic basis of phenotypic variability, which in turn will contribute to the better diagnosis and long-term management of patients.

影响睫状结构和功能的遗传病变会引起广泛的遗传收集 异质性和临床重叠的疾病，统称为纤毛病，是 以表型重叠和可变的外观和表现力为特征。在视网膜中，经过修改 纤毛在跨光感受器的蛋白质转运中起着不可或缺的作用，对于视网膜结构至关重要 和功能，如渐进的光感受器变性是许多人的标志所证明的 纤毛病。积累的证据表明，在某些纤毛病中突变的基因可以促进 在整个纤毛病谱中的因果和修饰等位基因，从而引起了顺式和反式的想法 演技等位基因可以导致纤毛病患者的突变负荷，并提供了这样的可能性 了解纤毛病的遗传结构可能会告知表型基础的机制 人类遗传疾病的变异性。为了探索这个概念，我们以前已经进行了公正的医学 重新陈述已知/预期对睫状生物发生和功能至关重要的基因 跨越严重程度的患者队列的各种队列。在RPGRIP1L中，已知引起新生儿的基因 致命的梅克梅克尔综合征（MKS）和中度严重的乔伯特综合征（JBTS），我们确定了一个 在中间种群频率下存在高度保存的A229T变化，并且显着 富含视网膜变性患者。使用跨学科的方法，我们继续证明 THR229等位基因是一种非中性变化，破坏了RPGRIP1L和RPGR之间的直接相互作用， X连锁性视网膜炎色素（XLRP）的最常见遗传原因。这些数据为我们提供了机会 探索纤毛病变视网膜表型中二次修饰的遗传机制， 开发可用于进一步探讨这种现象的模型。我们提出了两个目标。首先，受到动力 开发出强大模型来研究上毒的机会，我们将通过引入A229T的更改来建模 进入小鼠模型，随后将Thr229等位基因越过具有敏化睫状功能的线 确定该等位基因是否会诱导或加剧视网膜表型。第二，因为我们的初步 数据表明，RPGRIP1L也可能为非综合性视网膜变性造成同胞等位基因，我们 将将RPGRIP1L的突变分析扩展到扩展的非综合患者的队列和 匹配的控件。使用我们先前建立的体内互补策略，我们将测试 新发现的等位基因的致病潜力，并通过功能数据授权，我们将确定 视网膜变性中RPGRIP1L等位基因的总体富集。我们的研究完成将确定 视网膜变性患者的候选改性等位基因，生成新模型来研究这种 现象，有可能告知表型变异性的遗传基础，这反过来将 有助于对患者进行更好的诊断和长期治疗。