Pathogenesis of PCD Lung Disease

描述（由申请方提供）：原发性纤毛运动障碍（PCD）是一种隐性遗传异质性疾病，具有黏膜纤毛清除缺陷。这个正在进行的项目旨在使用全外显子组测序鉴定PCD中的其他致病突变，然后将分子病因与纤毛表型（超微结构，波形和搏动频率），体内鼻一氧化氮的产生和临床表型相关联。我们有强大的初步数据，离散的基因集有助于纤毛外动力蛋白臂（ODA），内动力蛋白臂（IDA），中央对（CP）和径向辐条（RS）的结构和功能。对于具有这些纤毛超微结构（电子显微镜，EM）缺陷的患者，鼻一氧化氮（nNO）产生均匀低（~ 20 ml/min），包括我们最近通过外显子组测序发现的导致ODA缺陷（CCDC 114）或ODA+IDA缺陷（SPAG 1; HEATR 2; LRRC 6; & ZMYND 10）的新基因突变的患者。我们现在正在鉴定越来越多的具有正常纤毛超微结构的PCD患者（在2010年时高达31%的PCD患者），并且这些患者中的50%在DNAH 11、RSPH 4A或我们最近发现的两个新基因（RSPH 1和CCDC 65）中具有双等位基因突变。在过去的3年中，我们在鉴定导致约60% PCD的15个基因突变方面取得了很大进展，但我们需要鉴定其余主要导致PCD的基因。我们现在正在对另外100名患者进行全外显子组测序（NIH 1X 0101 HL 115246 -01资助），由NHLBI支持的测序中心（耶鲁大学; R.利夫顿）。该外显子组测序项目将通过包括具有PCD相容临床表型但nNO值高于具有纤毛EM缺陷的PCD患者的典型值的患者来扩展我们对致病突变的搜索。后续研究将在生物医学中心进行，以验证新的基因发现，并表征人类纤毛气道细胞中的基因/蛋白质表达和功能。总之，这些研究将提供新的见解，在新的基因突变的关系，纤毛超微结构和功能缺陷。这些研究不仅将大大提高我们诊断PCD的能力，而且还将导致发现与正常纤毛超微结构相关的“温和”基因突变，并可能发现一些残留的纤毛功能。最终，这将允许开发PCD的临床基因检测，以及未来研究纤毛功能部分丧失在莫伊常见气道疾病（如慢性阻塞性肺病）易感性中的作用。

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.