Pathogenesis of PCD Lung Disease

描述(申请人提供)：原发性睫状体运动障碍(PCD)是一种隐性的，遗传异质性的疾病，有缺陷的粘液纤毛清除。这个正在进行的项目旨在使用整个外显子组测序来识别PCD中更多的致病突变，然后将分子病因学与纤毛表型(超微结构、波形和拍频)、体内鼻腔一氧化氮的产生以及临床表型联系起来。我们有可靠的初步数据表明，离散的基因集对纤毛动力蛋白外臂(ODA)、内动力蛋白臂(IDA)、中心对(CP)和放射状辐条(RS)的结构和功能起作用。对于有这些纤毛超微结构(电子显微镜，EM)缺陷的患者，鼻腔一氧化氮(NNO)的产生一致较低(~20ml/分钟)，包括我们最近通过外显子测序发现导致ODA缺陷的新基因突变的患者(CCDC114)或oda+IDA缺陷(SPAG1；HEATR2；LRRC6；&ZMYND10)。我们现在正在鉴定越来越多的纤毛超微结构正常的PCD患者(在UNC的PCD患者中高达31%)，其中50%的患者具有DNAH11、RSPH4A或我们最近发现的两个新基因(RSPH1和CCDC65)的双等位突变。在过去的三年里，我们在鉴定导致PCD的15个基因的突变方面取得了很大进展，但我们还需要确定剩余的主要导致PCD的基因。我们现在正在由NHLBI支持的测序中心(耶鲁大学；R.Lifton博士)对另外100名患者(NIH 1X0101HL115246-01赠款)进行完整的外显子组测序。这个外显子组测序项目将扩大我们对致病突变的搜索，包括那些具有PCD相容临床表型，但NNO值高于典型PCD患者睫状体EM缺陷的患者。后续研究将在北卡罗来纳大学进行，以验证新的基因发现，并表征人类纤毛呼吸道细胞的基因/蛋白质表达和功能。综上所述，这些研究将为新基因突变与纤毛超微结构和功能缺陷的关系提供新的见解。这些研究不仅将极大地提高我们诊断PCD的能力，而且还将导致发现与正常睫状体超微结构和可能存在的某些残留睫状体功能相关的“较温和的”基因突变。最终，这将使PCD的临床基因测试的发展，以及未来关于睫毛功能部分丧失在易患常见呼吸道疾病(如慢性阻塞性肺疾病)中的作用的研究。

DESCRIPTION (provided by applicant): Primary ciliary dyskinesia (PCD) is a recessive, genetically heterogeneous disorder with defective mucociliary clearance. This ongoing project is designed to identify additional disease-causing mutations in PCD using whole exome sequencing, and then to correlate the molecular etiologies with the ciliary phenotype (ultrastructure, wave form and beat frequency), production of nasal nitric oxide in vivo, and clinical phenotype. We have robust preliminary data that discrete sets of genes contribute to the structure and function of the ciliary outer dynein arm (ODA), inner dynein arm (IDA), and central pair (CP) and radial spokes (RS). For patients with these ciliary ultrastructural (electron microscopic, EM) defects, nasal nitric oxide (nNO) production is uniformly low (~ 20 ml/min), including patients with mutations we recently discovered by exome sequencing in novel genes that cause ODA defects (CCDC114) or ODA+IDA defects (SPAG1; HEATR2; LRRC6; & ZMYND10). We are now identifying an increasing number of PCD patients with normal ciliary ultrastructure (up to 31% of PCD patients at UNC) and 50% of those patients have biallelic mutations in DNAH11, RSPH4A, or two novel genes we recently discovered (RSPH1 & CCDC65). Over the past 3 years, we have made great progress in identifying mutations in 15 genes that cause ~60% of PCD, but we need to identify the remaining major PCD-causing genes. We are now whole exome sequencing 100 additional patients (NIH 1X0101HL115246-01 grant) by an NHLBI-supported sequencing center (Yale; Dr. R. Lifton). This exome sequencing project will extend our search for disease-causing mutations by including patients who have a PCD-compatible clinical phenotype, but with nNO values that are higher than typical for PCD patients with ciliary EM defects. Followup studies will be performed at UNC to validate novel gene discoveries, and characterize gene/protein expression and function in human ciliated airway cells. Taken together, these studies will provide new insights regarding the relationship of mutations in novel genes to ciliary ultrastructural and functional defects. These studies will not only greatly enhance our ability to diagnose PCD, but will also lead to discovery of "milder" genetic mutations associated with normal ciliary ultrastructure and likely some residual ciliary function. Ultimately, this will allow development of clinical genetic testing for PCD, and future studies of the role of partial loss of ciliary function in the predisposition to moe common airways diseases, such as chronic obstructive pulmonary disease.