Transmission electron microscopy study of suspected primary ciliary dyskinesia patients

Mansour Rezaei ,Hossein Ali Ghaffaripour,Hamid Reza Jamaati,Maryam Hasanzad,Mihan Pourabdollah,Hossein Toreyhi,Saied Mahmoudian,Amirali Soheili,Mahboobeh Karimi-Galougahi,Jahangir Ghorbani,Payam Tabarsi,Davood Mansouri,Atefeh Fakharian,Alireza Eslaminejad,Majid Marjani,Zahra Rodafshani,Maryam Sadat Mirenayat,Seyed Ali Ziai,Seyed Alireza Mahdaviani,Mohammad Varahram,Ali Akbar Velayati

doi:10.1038/s41598-022-06370-w

Abstract

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive condition often presenting with chronic respiratory infections in early life. Transmission electron microscopy (TEM) is used to detect ciliary ultrastructural defects. In this study, we aimed to assess ciliary ultrastructural defects using quantitative methods on TEM to identify its diagnostic role in confirming PCD. Nasal samples of 67 patients, including 37 females and 30 males (20.3 ± 10.7 years old), with suspected PCD symptoms were examined by TEM. The most common presentations were bronchiectasis: 26 (38.8%), chronic sinusitis: 23 (34.3%), and recurrent lower respiratory infections: 21 (31.3%). Secondary ciliary dyskinesia, including compound cilia (41.4%) and extra-tubules (44.3%), were the most prevalent TEM finding. Twelve patients (17.9%) had hallmark diagnostic criteria for PCD (class 1) consisting of 11 (16.4%) outer and inner dynein arm (ODA and IDA) defects and only one concurrent IDA defect and microtubular disorganization. Also, 11 patients (16.4%) had probable criteria for PCD (class 2), 26 (38.8%) had other defects, and 18 (26.9%) had normal ciliary ultrastructure. Among our suspected PCD patients, the most common ultrastructural ciliary defects were extra-tubules and compound cilia. However, the most prevalent hallmark diagnostic defect confirming PCD was simultaneous defects of IDA and ODA.

Highlights

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive condition often presenting with chronic respiratory infections in early life
These cilia play a pivotal role during the embryonic period by determining the laterality of organs; Situs Inversus is a common finding among PCD patients
This survey was the first study conducted in Iran to evaluate ciliary ultrastructural defects among patients presenting with symptoms attributable to PCD

Summary

Introduction

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive condition often presenting with chronic respiratory infections in early life. The ultrastructural ciliary impairments include the defect of the outer and/or inner dynein arms, the microtubular disorganization, and the rare absence of the central pair of microtubules (Fig. 2)[5]. PCD is an inherited genetic disorder that results from impaired ciliary beating caused mainly by an abnormal ciliary ultrastructure such as the ODA defect with or without the IDA defect[4] These cilia play a pivotal role during the embryonic period by determining the laterality of organs; Situs Inversus is a common finding among PCD patients. PCD cases develop into chronic upper and lower respiratory infections (such as Scientific Reports | (2022) 12:2375 |

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