Gileles-Hillel Alex, Mor-Shaked Hagar, Shoseyov David, Reiter Joel, Tsabari Reuven, Hevroni Avigdor, Cohen-Cymberknoh Malena, Amirav Israel, Brammli-Greenberg Shuli, Horani Amjad, Kerem Eitan, Breuer Oded
Pediatric Pulmonology and CF Unit, Department of Pediatrics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
Monique and Jacques Roboh Department of Genetic Research, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
ERJ Open Res. 2020 Dec 21;6(4). doi: 10.1183/23120541.00213-2020. eCollection 2020 Oct.
The diagnosis of primary ciliary dyskinesia (PCD) relies on clinical features and sophisticated studies. The detection of bi-allelic disease-causing variants confirms the diagnosis. However, a standardised genetic panel is not widely available and new disease-causing genes are continuously identified. To assess the accuracy of untargeted whole-exome sequencing (WES) as a diagnostic tool for PCD, patients with symptoms highly suggestive of PCD were consecutively included. Patients underwent measurement of nasal nitric oxide (nNO) levels, ciliary transmission electron microscopy analysis (TEM) and WES. A confirmed PCD diagnosis in symptomatic patients was defined as a recognised ciliary ultrastructural defect on TEM and/or two pathogenic variants in a known PCD-causing gene. Forty-eight patients (46% male) were enrolled, with a median age of 10.0 years (range 1.0-37 years). In 36 patients (75%) a diagnosis of PCD was confirmed, of which 14 (39%) patients had normal TEM. A standalone untargeted WES had a diagnostic yield of 94%, identifying bi-allelic variants in 11 known PCD-causing genes in 34 subjects. A nNO<77 nL·min was nonspecific when including patients younger than 5 years (area under the receiver operating characteristic curve (AUC) 0.75, 95% CI 0.60-0.90). Consecutive WES considerably improved the diagnostic accuracy of nNO in young children (AUC 0.97, 95% CI 0.93-1). Finally, WES established an alternative diagnosis in four patients. In patients with clinically suspected PCD and low nNO levels, WES is a simple, beneficial and accurate next step to confirm the diagnosis of PCD or suggest an alternative diagnosis, especially in preschool-aged children in whom nNO is less specific.
原发性纤毛运动障碍（PCD）的诊断依赖于临床特征和复杂的检查。双等位基因致病变异的检测可确诊该病。然而，标准化的基因检测 panel 尚未广泛应用，且不断有新的致病基因被发现。为评估非靶向全外显子测序（WES）作为 PCD 诊断工具的准确性，连续纳入了具有高度提示 PCD 症状的患者。患者接受了鼻一氧化氮（nNO）水平测量、纤毛透射电子显微镜分析（TEM）和 WES。有症状患者确诊为 PCD 的定义为 TEM 上公认的纤毛超微结构缺陷和/或已知 PCD 致病基因中的两个致病变异。共纳入 48 例患者（46%为男性），中位年龄为 10.0 岁（范围 1.0 - 37 岁）。36 例患者（75%）确诊为 PCD，其中 14 例（39%）患者的 TEM 正常。单独的非靶向 WES 的诊断率为 94%，在 34 名受试者的 11 个已知 PCD 致病基因中鉴定出双等位基因变异。当纳入 5 岁以下患者时，nNO<77 nL·min 不具有特异性（受试者操作特征曲线下面积（AUC）为 0.75，95%CI 为 0.60 - 0.90）。连续的 WES 显著提高了幼儿中 nNO 的诊断准确性（AUC 为 0.97，95%CI 为 0.93 - 1）。最后，WES 在 4 例患者中确立了替代诊断。在临床怀疑 PCD 且 nNO 水平较低的患者中，WES 是确认 PCD 诊断或提示替代诊断的简单、有益且准确的下一步检查，尤其是在 nNO 特异性较低的学龄前儿童中。
