Transmission electron microscopy study of suspected primary ciliary dyskinesia patients

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

doi:10.1038/s41598-022-06370-w

Cited by 8 publications

(6 citation statements)

References 27 publications

(44 reference statements)

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“…Regarding TEM findings, in contrast to the current study that showed ODA loss and MTD + IDA loss to be equally the most common hallmark defects, ODA + IDA loss was the most common hallmark defect reported in previous studies in the Kingdom of Saudi Arabia (KSA), Oman, and Iran 32–34 . ODA absence as a Class 1 hallmark defect was not reported among the Iranian cohort 34 …”

Section: Discussioncontrasting

confidence: 99%

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Primary ciliary dyskinesia in Egypt: First report of cilia ultrastructural defects and novel genetic variants

Shoman,

Elbanna,

Fassad

et al. 2024

Pediatric Pulmonology

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BackgroundPrimary ciliary dyskinesia (PCD) is a genetic disorder that follows several inheritance patterns predominately autosomal recessive. It is caused by aberrant motile cilia structure and/or function. Diagnosis of PCD is challenging, involving complex technical steps and requiring special expertise. Here, we report the first attempt to employ transmission electron microscopy (TEM) to precisely diagnose PCD in Egypt. The study aims to outline the findings of diagnostic procedures, including TEM and genetic analysis, carried out on a cohort of Egyptian patients clinically suspected of having PCD.MethodsA cohort of 48 individuals underwent testing to determine their PCD status. The diagnostic modalities used included genetic and TEM analysis. Clinical features and diagnostic test outcomes were described.ResultsPCD was confirmed in 27 of the 48 participating cases. Class 1 hallmark defects were the most commonly detected TEM findings. Outer dynein arm defect in addition to microtubular disorganization with inner dynein arm loss was found equally to be the most common diagnostic defects in the confirmed cases. A highly heterogeneous genetic background was found with 14 different affected genes. Of these, CCDC39 was the most commonly mutated one. The variants, c.430‐1G>A in DNAAF6, c.8099C>T in DNAH11, c.263T>C in DNAL1, c.1154dup in NEK10, c.487C>T in HYDIN, and c.90+1G>C in CCDC39 gene were detected novel variants.ConclusionDiagnosis of PCD is challenging especially in low‐ and middle‐income countries. As there is no single reference diagnostic test, integrating diagnostic modalities, such as TEM and genetics, can enhance diagnosis.

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Section: Discussioncontrasting

confidence: 99%

“…[32][33][34] ODA absence as a Class 1 hallmark defect was not reported among the Iranian cohort. 34 Class 2 defects affected 5/34 (14.70%) of the adequate samples.…”

Section: Discussionmentioning

confidence: 83%

Primary ciliary dyskinesia in Egypt: First report of cilia ultrastructural defects and novel genetic variants

Shoman,

Elbanna,

Fassad

et al. 2024

Pediatric Pulmonology

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“…Although the lack of any other PCD diagnostic test limited the direct comparisons that could be made between individual clinical diagnoses and the corresponding TEM observations, clinical suspicion of PCD and ciliary ultrastructure overall appeared concordant in 43% of the cases. This value compares well with other recent PCD-TEM-only reports from resource-limited settings, for example 17.9% in an Iranian study ( 23 ), 34% in the Palestinian cohort ( 11 ) and 43% (all cases) −70% (only cases with high clinical suspicion) in a Brazilian study ( 6 ). These studies were based on large numbers of clinically suspected PCD cases of all age groups, in contrast to the current small pediatric study in which correlation between clinical and ultrastructural data was probably due to the pediatric pulmonologists' heightened awareness of PCD as part of a diagnostic differential, to the small sample size, and to the lack of any other test to corroborate the clinical - TEM findings.…”

Section: Discussionsupporting

confidence: 88%

Ultrastructure for the diagnosis of primary ciliary dyskinesia in South Africa, a resource-limited setting

Birkhead,

Otido,

Mabaso

et al. 2023

Front. Pediatr.

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IntroductionInternational guidelines recommend a multi-faceted approach for successful diagnoses of primary ciliary dyskinesia (PCD). In the absence of a gold standard test, a combination of genetic testing/microscopic analysis of structure and function/nasal nitric oxide measurement is used. In resource-limited settings, often none of the above tests are available, and in South Africa, only transmission electron microscopy (TEM) is available in central anatomical pathology departments. The aim of this study was to describe the clinical and ultrastructural findings of suspected PCD cases managed by pediatric pulmonologists at a tertiary-level state funded hospital in Johannesburg.MethodsNasal brushings were taken from 14 children with chronic respiratory symptoms in keeping with a PCD phenotype. Ultrastructural analysis in accordance with the international consensus guidelines for TEM-PCD diagnostic reporting was undertaken.ResultsTEM observations confirmed 43% (6) of the clinically-suspected cases (hallmark ultrastructural defects in the dynein arms of the outer doublets), whilst 57% (8) required another PCD testing modality to support ultrastructural observations. Of these, 25% (2) had neither ultrastructural defects nor did they present with bronchiectasis. Of the remaining cases, 83% (5) had very few ciliated cells (all of which were sparsely ciliated), together with goblet cell hyperplasia. There was the apparent absence of ciliary rootlets in 17% (1) case.DiscussionIn resource-limited settings in which TEM is the only available testing modality, confirmatory and probable diagnoses of PCD can be made to facilitate early initiation of treatment of children with chronic respiratory symptoms.

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“…Indeed, EM has been used to further investigate the detailed structures of cell organelles to validate potential novel findings discovered through research studies. For example, EM has been used to: a) assess ciliary ultrastructural defects in ciliary disorders 13 ; b) identify stored material in lysosomal storage disorders, including neuronal ceroid lipofuscinoses and Batten disease 14 ; and c) isolate highly infectious and contagious microorganisms, primarily viruses, to enable production of vaccines in microbial diseases, e.g. SARS-CoV-2/coronavirus.…”

Section: Discussionmentioning

confidence: 99%

Investigating ultrastructural morphology in MIRAGE syndrome (SAMD9)-derived fibroblasts using transmission electron microscopy.

et al. 2023

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Background: Heterozygous de novo variants in the gene SAMD9 cause the complex multisystem disorder, MIRAGE syndrome. Patients are characterised by myelodysplasia, infections, growth restriction, adrenal insufficiency, gonadal dysfunction and enteropathies. Pathogenic variants in SAMD9 are gain-of-function and enhance its role as a growth repressor, leading to growth restriction of many tissues. Two studies have reported changes in skin fibroblasts derived from MIRAGE patients, more specifically identifying enlarged endosomes. We have also previously shown subtle changes in endosome size in patients’ fibroblasts compared to controls. However, these variations in endosomes were not as marked as those described in the literature. Methods: We have performed an observational study using transmission electron microscopy (EM) in a larger number of cells derived from three patients’ fibroblasts to assess ultrastructure morphology compared to control images. Results: Consistent changes were observed in cell organelles in all patient samples. In particular, increased endosomal activity was detected, characterised by augmented pinocytosis and vesicle budding, increased endosome number, as well as by large lysosomes and endosomes. Endoplasmic reticulum was also prominent. Mitochondria appeared enlarged in selected cells, possibly due to cellular stress. Cell nuclei did not display major differences compared to controls. Conclusions: EM is a powerful tool to investigate morphological features of tissues and cell organelles, although EM data could be affected by sample preparation methodology, therefore potentially explaining the variability between independent studies, and its analysis can be dependent on the experience of the researcher. The increased endosomal activity we have observed in patients’ fibroblasts could indicate that SAMD9 regulates endocytosis of receptors, acting as an endosome fusion facilitator, or in lysosomal activation. However, the precise mechanism(s) by which SAMD9 regulates cell growth is still not fully understood, and further studies are needed to elucidate its pathogenic pathway and develop therapeutic approaches to support patients.

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Transmission electron microscopy study of suspected primary ciliary dyskinesia patients

Cited by 8 publications

References 27 publications

Primary ciliary dyskinesia in Egypt: First report of cilia ultrastructural defects and novel genetic variants

Primary ciliary dyskinesia in Egypt: First report of cilia ultrastructural defects and novel genetic variants

Ultrastructure for the diagnosis of primary ciliary dyskinesia in South Africa, a resource-limited setting

Investigating ultrastructural morphology in MIRAGE syndrome (SAMD9)-derived fibroblasts using transmission electron microscopy.

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