Primary ciliary dyskinesia (PCD) is an inherited disorder of the motile cilia. Early accurate diagnosis is important to help prevent lung damage in childhood and to preserve lung function. Confirmation of a diagnosis traditionally relied on assessment of ciliary ultrastructure by transmission electron microscopy (TEM), however >40 known PCD genes has made the identification of bi-allelic mutations a viable alternative to confirm diagnosis. TEM and genotyping lack sensitivity and research to improve accuracy of both is required. TEM can be challenging when a subtle or partial ciliary defect is present or affected cilia structures are difficult to identify due to poor contrast. Here we demonstrate software to enhance TEM ciliary images and reduce background by averaging ciliary features. This includes an option to classify features into groups based on their appearance, to generation multiple averages when a nonhomogeneous abnormality is present. We validated this software on images taken from subjects with well characterised PCD caused by variants in the outer dynein arm (ODA) heavy chain gene DNAH5. Examining more difficult to diagnose cases, we detected (i) regionally restricted absence of the ODAs away from the ciliary base, in a subject carrying mutations in DNAH9; (ii) loss of the typically poorly contrasted inner dynein arms; (iii) sporadic absence of part of the central pair complex in subjects carrying mutations in HYDIN, including one case with an unverified genetic diagnosis. We show this easy to use software can assist in detailing relationships between genotype and ultrastructural phenotype and diagnosing PCD by TEM.

中文翻译：

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PCD检测：通过图像平均和分类增强睫状功能

原发性睫状运动障碍（PCD）是活动性纤毛的遗传性疾病。早期准确的诊断对于帮助预防儿童肺损伤和保持肺功能很重要。传统上，对诊断的确认依赖于通过透射电子显微镜（TEM）评估睫状超微结构，但是，> 40个已知的PCD基因使双等位基因突变的鉴定成为确诊的可行选择。TEM和基因分型缺乏敏感性，需要进行研究以提高两者的准确性。当存在细微或部分的睫状体缺陷或由于对比度差而难以识别受影响的纤毛结构时，TEM可能具有挑战性。在这里，我们演示了通过平均睫状功能来增强TEM睫状图像并减少背景的软件。这包括一个选项，可根据外观将特征分类为组，当存在非均匀异常时生成多个平均值。我们在从特征明确的PCD受试者拍摄的图像上验证了该软件，该受试者的特征是由外部动力系统（ODA）重链基因DNAH5的变异引起的。通过检查更难以诊断的病例，我们发现（i）在携带DNAH9突变的受试者中，远离睫状体的区域限制了ODA的缺失；（ii）典型的对比度较差的内达因臂丢失；（iii）携带HYDIN突变的受试者偶有中央对复合体的一部分缺失，包括一例未经基因诊断的病例。我们展示了这个易于使用的软件可以帮助详细描述基因型和超微结构表型之间的关系，并通过TEM诊断PCD。