Diagnosis of Primary Ciliary Dyskinesia. An Official American Thoracic Society Clinical Practice Guideline

An Innovative Transmission Electron Microscopy-Based Ultrastructural Imaging Methodology for the Diagnosis of Respiratory Ciliary Disorders

Transmission electron microscopy is a classical methodology for diagnosing many ciliary disorders. However, heterogeneity in sampling, low yield of ciliary epithelium by cytology, improper fixation, and different orientations of cylindrical axes of cilia section create difficulties in achieving the appropriate ciliary ultrastructure for diagnosis. We have reported an improvement in the number and proportion of ciliary epithelial cells up to 32 times. These include cleaning the nose before sample collection, changing the collection brush used for the cervical cytology (eight times), and paired nose collection (four times). We have optimized the primary fixation to preserve cilia ultrastructure, modified ultra-sectioning, and improved the number of reportable ultrastructure of cilia by tilting the sample angles of α axes (up to ±40°) and β axes (up to ±25°). These optimizations resulted in ∼20 times more reportable cilia (parallel to cylindrical axes concerning the electron beam, clearly visible dynein arms, 9 + 2 patterns, and compound cilia). This resulted in an enhanced diagnosis of ciliary disorders, up to 67% (reported in 135 among 200 patients), compared with 5% achieved using conventional routine practices at our facility. With certain advancements in conventional method, we could achieve an accuracy comparable to the new sophisticated cryo-electron tomography imaging.

Management of middle ear disease in pediatric primary ciliary dyskinesia

INTRODUCTION

Primary ciliary dyskinesia (PCD) adversely affects the middle ear from early childhood resulting in otitis media with effusion (OME) and conductive hearing loss (CHL). Chronic otorrhea and tympanic membrane (TM) perforation are serious postoperative complications from tympanostomy tube (TT) placement. Management of OME and CHL has been debated for decades. This study reports on a proposed management schema for the middle ear in individuals with PCD.

METHODS

A pediatric PCD cohort was retrospectively reviewed at Children's Hospital Colorado (CHCO) using electronic health record systems. Paired middle-ear/audiologic data for all subjects at their most recent CHCO visits were organized in a 4-age-group grid to compare clinical/audiologic outcomes between no-TT and TT subgroups.

RESULTS

68 PCD subjects with middle-ear and audiologic data were tabulated. No-TT and TT subgroup comparisons showed no difference in clinical (normal TM and OME prevalence) and hearing [CHL percentage and pure-tone average (PTA)] outcomes across 4 age-groups except for higher percentage of normal TM (10 to <15 years category; p = 0.006) and fewer hearing loss ears (≥15 years category; p = 0.008), both favoring the no-TT subgroup. There were 9/13 (subjects/ears) in the TT subgroup with TM perforations, and a total of 130 sets of TT and other medical/surgical procedures were performed in this sub-cohort.

CONCLUSION

Children with PCD have a high prevalence of otologic complications. A schema is proposed to restrict the indications for TT placement and guide active management of CHL with the goal of preventing adverse sequalae of OME and achieving best clinical outcomes.

Overlapping Clinical Phenotypes in Patients with Primary Ciliary Dyskinesia or Activated Phosphoinositide 3-Kinase Delta Syndrome

Primary ciliary dyskinesia and activated phosphoinositide 3-kinase delta syndrome type 1 present similarly, with recurrent respiratory infections and reduced nasal nitric oxide levels. When diagnostic confirmation of primary ciliary dyskinesia with genetic testing and/or ciliary electron microscopy is inconclusive, activated phosphoinositide 3-kinase delta syndrome type 1 and other inborn errors of immunity must be investigated.

Primary ciliary dyskinesia cases bronchoscopic sampling and TEM analysis: sampling & diagnosis in PCD

Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous disorder characterized by impaired ciliary structure and function, leading to chronic respiratory symptoms and recurrent infections. Despite its clinical significance, PCD diagnosis remains challenging due to its variable presentation and the lack of a gold standard diagnostic test. Specific clinical criteria, including neonatal respiratory distress and laterality defects, aid in suspicion of PCD, but confirmatory diagnosis often requires a combination of tests. In this study, we aimed to assess the efficacy of bronchoscopic techniques in obtaining respiratory epithelial samples for transmission electron microscopy (TEM) analysis. We enrolled adults with bronchiectasis and suspected PCD who underwent fiberoptic bronchoscopy. Bronchial forceps and brush biopsies were obtained from specific bronchial segments under conscious sedation. Tissue samples were processed for TEM analysis to identify ultrastructural axonemal defects associated with PCD. Our study included 10 patients (3 females, 7 males) aged 19-38 years, with detailed demographics and clinical characteristics provided. Evaluation of tracheobronchial biopsy samples revealed higher histological scores for the presence of ciliated cells and transverse sections of cilia in pellets obtained from brush biopsies and fixative solutions of forceps biopsy compared to forceps biopsy tissue samples. Electron microscopic examination of ultra-thin sections demonstrated abundant ciliated cells and abnormal cilia structures, aiding in the diagnosis of PCD in pellets. PCD represents a significant etiology of bronchiectasis, emphasizing the need for accurate diagnosis and appropriate management strategies. Our findings highlight the importance of bronchoscopic techniques, including bronchial brushing alongside forceps biopsies, in enhancing diagnostic yield and guiding timely intervention to improve patient outcomes.

Pediatric Pulmonology 2024 Year in Review: Rare and Diffuse Lung Disease

The field of pediatric rare and diffuse lung diseases continues to advance, with ongoing research deepening our understanding of the diagnosis and treatment of conditions such as children's interstitial and diffuse lung disease (chILD), non-cystic fibrosis (CF) bronchiectasis, and pulmonary complications of childhood cancer. Recent publications in Pediatric Pulmonology and other journals in 2024 have highlighted new insights into the pathophysiology, disease progression, and emerging diagnostic tools for these rare lung conditions, as well as innovative therapeutic approaches. This review features these important advancements within the context of current diagnostic practices and clinical care for pediatric patients with rare and diffuse lung diseases.

Genotype-Phenotype Correlation in a Group of Italian Patients With Primary Ciliary Dyskinesia

INTRODUCTION

Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder characterized by abnormalities in the motile cilia. Diagnosis could be hard to make, but genetic analysis could be important for the diagnosis and for defining prognosis.

AIM OF THE STUDY

To evaluate the clinical, ultrastructural, and molecular characteristics of a cohort of PCD subjects.

MATERIALS AND METHODS

The study cohort included PCD patients enrolled in two Italian centers. Clinical data were retrospectively collected consulting medical records. All patients underwent nasal brushing and peripheral blood sampling for ultrastructural analysis of motile cilia and genetic testing, respectively.

RESULTS

A total of 39 patients with PCD were enrolled (median age 25.5 years, range 2.5-54.3 years). All patients showed common clinical features, which included SIT in 22/39 (56.4%), chronic rhinitis in 31/39 (79.5%), chronic sinusitis in 26/37 (66.7%), chronic cough in 32/39 (82.1%), and neonatal respiratory distress in 46.2% (18/39). The genetic defect was identified in 27/39 patients (69.2%), while a diagnostic ultrastructure was found in 27/35 (77.1%). Assessing genotype-phenotype correlations, subjects with biallelic pathogenic variants in CCDC39 and CCDC40 genes had a significantly lower forced expiratory volume in the first second of exhalation value (p = 0.017) than subjects with pathogenic variants in DNAH5 or in other PCD-related genes.

CONCLUSIONS

Our study further highlights the high heterogeneity of ultrastructural defects and genetics characterizing patients with PCD, as well as providing additional evidence that patients with biallelic pathogenic variants in CCDC39 or CCDC40 display a worse clinical phenotype than patients with pathogenic variants in other PCD genes.

Risk factors for bronchiolitis obliterans development in children after Mycoplasma pneumoniae pneumonia: a retrospective study of 981 patients

BACKGROUND

Bronchiolitis obliterans (BO) is a rare and severe chronic pulmonary condition in children following an injury to lower respiratory tract lesion. Mycoplasma pneumoniae (M. pneumoniae) is the second etiology of post-infectious bronchiolitis obliterans (PIBO). The aim of this study was to determine risk factors for PIBO development in children after M. pneumoniae pneumonia.

METHODS

This retrospective study enrolled 981 children admitted to Beijing children's hospital due to M. pneumoniae pneumonia between January 2016 and December 2022. The medical records of the PIBO and non-PIBO groups, including demographic, clinical, radiologic, and laboratory data were analyzed by multivariate logistic regression to reveal PIBO development-associated risk factors.

RESULTS

Seventy-two of the study patients developed PIBO after M. pneumoniae pneumonia. Multivariate analysis showed that large lobar consolidation (OR 4.06, 95% CI 1.18-14.03), diffuse bronchiolitis (OR 11.78, 95% CI 3.28-42.22), co-infection (OR 3.65, 95% CI 1.60-8.33), atopic conditions (OR 12.32, 95% CI 5.2-29.11), bronchial mucus plug (OR 2.48, 95% CI 1.10-5.58), CPR (OR 1.01, 95% CI 1.00-1.02), mechanical ventilation (OR 2.95, 95% CI 1.00-8.67), and duration of fever (OR 1.19, 95% CI 1.05-1.37) were significantly associated with development of PIBO after M. pneumoniae pneumonia.

CONCLUSIONS

In children with M. pneumoniae pneumonia, large lobar consolidation, diffuse bronchiolitis, co-infections, atopic conditions, bronchial mucus plug, CRP, mechanical ventilation, and duration of fever appeared as prominent independent risk factors for PIBO. Timely application of HRCT could provide a basis for the early prediction of PIBO development in children.

Analysis of clinical and genetic features in a pediatric patient with Kartagener syndrome caused by compound heterozygous mutations in the DNAH5 gene: a case study and literature review

Kartagener syndrome (KS), a subtype of primary ciliary dyskinesia (PCD), is a rare genetic disorder characterized by situs inversus, chronic sinusitis, bronchiectasis, recurrent respiratory infections, and impaired ciliary function. It is diagnosed through physical examination, imaging techniques such as computed tomography (CT), nasal nitric oxide measurement, genetic testing, and pulmonary function tests. We present a case study of a 15-year-and-11-month-old male patient with KS complicated by sinusitis, secretory otitis media, and bronchiectasis. The patient exhibited situs inversus totalis, affecting the lungs, heart, and abdominal organs. Treatment included antibiotics for infection, mucolytics, and pulmonary rehabilitation. Postural drainage and bronchoscopy were performed for lung lavage. Following treatment, the patient's respiratory symptoms improved, and lung function tests showed improvement. A literature review identified a high prevalence of lung and heart transpositions in Chinese patients with PCD, while abdominal organ transposition was less commonly reported. Genetic analysis revealed compound heterozygous mutations in the DNAH5 gene, specifically c.12279 + 1 G > A (exon 71, NM_001369) and c.9457 C > T (exon 56, NM_001369), including the newly discovered variant c.9457 C > T (exon 56, NM_001369). This novel mutation expands the genetic landscape associated with KS, providing further insights into the underlying genetic basis of the condition. The study emphasizes the clinical features, the limited reporting of abdominal organ transposition, the genetic basis, and the treatment of KS, thereby contributing to the understanding and management of this condition.

Assessment of liquid media requirements for storing and evaluating respiratory cilia motility

Mucociliary clearance is critical for maintaining normal lung function. Respiratory cilia which drive mucociliary clearance are commonly studied by measuring cilia beat frequency (CBF). There is currently significant variation within the literature regarding what is a normal value for CBF, this may be due in part to the large variety of liquid media used to suspend, maintain, and image ciliated cells. This study aimed to conduct a thorough examination to assess how media choice influences respiratory cilia motility. To accomplish this, Adult C57/BL6 mouse trachea samples were incubated in eight commonly used liquid media including: Saline, Dulbecco's Phosphate-Buffered Saline (DPBS), Hanks' Balanced Salt Solution (HBSS), Medium 199 (M199), Dulbecco's Modified Eagle's Medium (DMEM), Roswell Park Memorial Institute Medium (RPMI), Minimum Essential Medium (MEM), and Leibovitz's L-15 Medium (L-15); with or without 10% FBS supplementation. The effects of storage time (0-12 hours) and storage temperature (4 °C or room temperature) were also assessed. All media except saline were found to be equally effective in maintaining cilia function in airway samples that were freshly harvested and immediately imaged. Saline, however, significantly reduced the number of cells with motile cilia. A more complex pattern emerged when samples were stored before imaging. In saline, cilia function was significantly impaired after just one hour of storage. Samples stored in all other media showed strong maintenance of motile cilia function, with only minor changes. Notably, cilia function was better preserved with storage at 4 °C, while room temperature storage generally led to significant increases in CBF, especially in media containing FBS. Lastly, FBS supplementation was essential for maintaining cilia motility in L-15 media, as L-15 without FBS resulted in significant decreases in cilia motility following storage at either 4 °C or room temperature. In conclusion, saline should only be used if cilia are to be imaged immediately, as cilia stored in saline quickly lose motile function. All other commonly used media appear equally capable of maintaining motile cilia function for up to 12 hours when stored at 4 °C. Surprisingly, DPBS was just as effective as more expensive media in preserving ciliated samples. Storing ciliated tissue at room temperature generally leads to increased CBF, particularly in media containing FBS. Finally, L-15 media alone specifically requires the addition of 10% FBS to maintain cilia motility. These findings provide a valuable foundation for standardizing the handling, collection, and transport of ciliated samples for motile cilia assessment.

Whole exome sequencing enhances diagnosis of hereditary bronchiectasis

BACKGROUND

Hereditary bronchiectasis refers to a subset of bronchiectasis related to genetic mutations, presenting with common clinical features. Historically, diagnosing this condition has been difficult due to the inaccessibility of diagnostic services coupled with a lack of awareness of the syndrome. We hypothesize that whole exome sequencing (WES) in patients with supporting clinical features, combined with non-genetic testing methods, will enhance the diagnosis of hereditary bronchiectasis.

RESULTS

In total, 87 patients with clinical features suggestive of hereditary bronchiectasis, such as diffuse bronchiectasis (≥ 2 lobes) combined with early onset symptoms, recurrent otitis media, rhinosinusitis, infertility, organ laterality defects or a family history of bronchiectasis, were included in this study. Among them, 49.4% (43/87) were diagnosed with hereditary bronchiectasis, including 15 patients with cystic fibrosis, 27 patients with primary ciliary dyskinesia, and 1 patient with immunodeficiency-21. The combined use of WES and non-genetic testing methods significantly improved the diagnostic rate of hereditary bronchiectasis compared to non-genetic testing alone (47.1% vs. 25.3%, P = 0.005). Re-analysis of negative commercial genetic tests led to two additional diagnoses, though this increase was not statistically significant (47.1% vs. 49.4%, P = 0.879).

CONCLUSIONS

We have described the supporting clinical features of patients with hereditary bronchiectasis. Clinicians should recommend WES for patients exhibiting these characteristics, in combination with accessible non-genetic testing methods, to maximize diagnostic accuracy. For patients with negative initial genetic test results, re-analysis of WES data may facilitate obtaining a new diagnosis.

Empowering limited-resource countries: collaborating with expert centers for diagnosis of primary ciliary dyskinesia

Introduction

Primary ciliary dyskinesia (PCD) is an autosomal recessive rare disease caused by alterations in ciliary structure and function. Without a unique gold standard diagnostic test, the European Respiratory Society and the American Thoracic Society recommend using various diagnostic techniques to improve accuracy. This study aimed to demonstrate the effectiveness of immunofluorescence (IF) analysis in the diagnosis of PCD cases with uncertain genetic results and to demonstrate the importance of international collaboration in the diagnosis of PCD.

Methods

In collaboration with IF specialists at the University of Münster, individuals with inconclusive results in the Marmara University PCD panel consisting of the 22 most common genes and clinically suggestive of PCD were included in the study. IF imaging determined the subcellular localization of DNAH5 and GAS8 in respiratory epithelial cells. Nasal nitric oxide measurements, high-speed video microscopy (HSVM) analysis, and genetic analyses were performed.

Results

19 patients were evaluated. The median age (25-75p) was 15 years (10-20 years) with 12 (63.2%) males. Three cases (15.7%) showed an absence of DNAH5, and one (5.3%) had a proximal distribution of DNAH5 in the ciliary axoneme. One case (5.3%) had cells without cilia, indicating a possible ciliogenesis defect. All individuals with abnormal IF analysis had a PICADAR score of 6 or above, and their cilia were immotile in HSVM.

Discussion

Consistent with the IF finding suggesting a ciliogenesis defect, further genetic analysis revealed biallelic pathogenic variants in CCNO in the affected individual. The absence of DNAH5 in the respiratory epithelial cells of an individual carrying heterozygous pathogenic splice variants in DNAH5 suggests the need for further genetic analysis. This study underscores the importance of international collaboration in diagnosing rare diseases like PCD.

Genetic spectrum and genotype-phenotype correlations in DNAH5-mutated primary ciliary dyskinesia: a systematic review

BACKGROUND

Primary ciliary dyskinesia (PCD), a rare ciliopathy disorder, is caused by variants in multiple genes, with DNAH5 being one of the most frequently implicated. However, the precise relationship between variant type or location in the DNAH5 gene and the clinical heterogeneity remains elusive. The present systematic review aims to provide critical insights into the impact of the molecular nature of DNAH5 variants on PCD phenotypes.

METHODS

We enrolled all reported cases of PCD with biallelic pathogenic variants in the DNAH5 gene to date, and evaluated genotype-phenotype correlations in these patients, employing truncating (TV) and missense (MV) variant-carrying as grouping criteria.

RESULTS

A total of 323 PCD patients with the DNAH5 variants were included, with 14.55% of these patients were diagnosed as Kartagener syndrome. Pediatric and adult patients exhibited distinct clinical features, including varying incidences of bronchiectasis, infertility, neonatal respiratory distress (NRD), ciliary ultrastructural defects distributions, and lung function (all p < 0.05). With regard to mutational patterns, truncating variants in DNAH5 were clustered in the 1200-3200 amino acid region, and were more prevalent in children compared to adult (p < 0.0001). Most missense variants are clustering in the linker, AAA + ATPase and AAA-lid domains. The most frequently observed mutation, c.10815delT, was prevalent in Europe and America, whereas c.8030G > A was more common in China and Asia. In terms of genotype-phenotype correlations, individuals with the TV/TV genotype exhibited a higher proportion of NRD and earlier onset compared to those with MV-carrying genotypes, both in overall population and in pediatric patients (all p < 0.05). Patients with the TV/TV genotype exhibited worse lung function compared to those with MV-carrying genotypes.

CONCLUSION

The study underscores the broad mutational spectrum and high phenotypic heterogenicity in DNAH5-related PCD patients. The presence of biallelic truncating variants may predispose patients to earlier disease onset and poorer lung function.

A Pilot Study of Primary Ciliary Dyskinesia: Sleep-Related Disorders and Neuropsychiatric Comorbidities

Sleep disorders are characterized by impaired quality, timing, and amount of sleep, resulting in daytime distress and functioning. Primary ciliary dyskinesia (PCD) is a rare genetic condition characterized by oto-sino-pulmonary manifestations with multiple comorbidities, including sleep disorders. Background/Objectives: This pilot study aims to assess sleep disorders and neuropsychiatric comorbidities in Puerto Rican patients with the RSPH4A (c.921+3_921+6delAAGT) PCD founder mutation. However, the literature on sleep-related disorders and their neuropsychiatric comorbidities in PCD is limited. Methods: A cohort of fifteen patients with the RSPH4A (c.921+3_921+6delAAGT) founder mutation (six pediatric, nine adults) were evaluated for sleep quality, cognitive, neurodevelopmental history, and mood-related manifestations, followed by diagnostic polysomnography for sleep-disordered breathing and other sleep-related disorder detection. Results: Twelve out of fifteen (12/15, 80%) patients presented with sleep-related disorders, particularly obstructive sleep apnea where the median Pediatric AHI was 1.25/h (IQR: 1.1-1.75/h), T < 90: 0.1 min (IQR: 0-1.9 min) and adult AHI 1.3 (IQR: 0.9-8), T < 90: 0.2 min (IQR: 0-3.5 min). PCD patients also presented complex sleep behaviors, and more than half had sleep-related movement manifestations such as sleep-related Bruxism, PLMS, among others. All pediatric patients with OSA met criteria for an anxiety disorder, with a GAD-7 of 13 (IQR: 10.5-15.8); this association was not clearly seen in adults. Conclusions: Patients with PCD RSPH4A exhibited multiple sleep and neuropsychiatric manifestations, particularly OSA, sleep-related movement disorders and complex sleep behaviors. Further studies are needed to determine if these manifestations result from obstructive breathing, sleep mechanism disruption, or other neurodevelopmental impairment associated with this ciliopathy.

Impact of Aerobic Exercise on Oxygenation, Pulmonary Function, and Nasal Nitric Oxide in Primary Ciliary Dyskinesia

Background

Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder characterized by impaired mucociliary clearance, resulting in chronic respiratory complications. While exercise benefits respiratory health, its impacts on PCD remain understudied.

Objective

The objective of this study was to assess how moderate aerobic exercise influences FEV1, SpO2, and nNO levels in PCD patients, with a focus on short-term post-exercise changes.

Methods

This is a matched case-control pilot study involving 12 PCD patients homozygous for the RSPH4A (c.921+3_921+6del) mutation and 12 healthy controls (HC). Baseline FEV1, SpO2, and nNO levels were measured before participants underwent a six-minute exercise challenge test (ECT) on a stationary bicycle. Post-exercise measurements included FEV1 at 5, 10, 15, and 20 minutes, nNO after final spirometry, and SpO2 at 5 minutes.

Results

The PCD group experienced a significant increase in SpO2 from 95.5% ± 2.1 to 97.7% ± 1.5 post-exercise (p < 0.05), while the HC group had stable SpO2 levels with a minor increase from 97.9% ± 1.5 to 98.9% ± 1.4 (p = 0.14). No significant changes in FEV1 or nNO levels were observed post-exercise in either group. One HC participant exhibited exercise-induced bronchoconstriction.

Conclusion

Aerobic exercise improves oxygenation in PCD patients without adverse effects on pulmonary function or nNO levels. Further research is necessary due to the small sample size and genetic homogeneity to confirm these findings and evaluate long-term outcomes. Moreover, this pilot study highlights the safety and potential respiratory benefits of aerobic exercise in PCD patients, supporting further investigation into its role in clinical management.

Comparison of characteristics and immune responses between paired human nasal and bronchial epithelial organoids

BACKGROUND

The nasal epithelium, as part of a continuous and integrated airway epithelium, provides a more accessible sample source than the bronchial epithelium. However, the similarities and differences in gene expression patterns and immune responses between these two sites have not been extensively studied.

RESULTS

Four lines of matched nasal and bronchial airway epithelial cells obtained from the four patients were embedded in Matrigel and cultured in thechemically defined medium to generate patient-derived nasal organoids (NO) and bronchial organoids (BO). Histologic examination of nasal organoid tissue revealed high similarity and a reduced ciliary beat frequency compared to bronchial organoid tissue. Whole exome sequencing revealed that over 99% of single nucleotides were shared between the NO and matched BO and there was a 95% overlap in their RNA transcriptomes. RNA sequencing analysis of differentially expressed genes indicated a significant reduction in the immune response in NO. RSV infection revealed more productive replication in NO, with a downregulated immune pathway identified by RNA sequencing analysis and upregulated levels of pro-inflammatory cytokines in culture supernatants in NO compared to BO.

CONCLUSIONS

NO and BO serve as robust in vitro models, faithfully recapitulating the biological characteristics of upper respiratory epithelial cells. The different regions of respiratory epithelial cells exhibit distinct immune responses, underscoring their complementary roles in exploring airway immune mechanisms and disease pathophysiology.

Evaluation of the Clinical and Genetic Characteristics of Primary Ciliary Dyskinesia Patients With Situs Inversus Totalis

BACKGROUND

Situs inversus totalis (SIT) is present in approximately 40%-50% of patients with primary ciliary dyskinesia (PCD). We evaluated the relationships between novel genetic results and the clinical and radiological characteristics of PCD patients with SIT.

METHODS

The study included 48 patients diagnosed with PCD and SIT. Demographic and clinical features, disease-related scores (Bhalla, Primary Ciliary Dyskinesia Rule [PICADAR], and American Thoracic Society [ATS]), and genetic analyses were retrospectively assessed.

RESULTS

The median age of patients was 13 (6.5-16) years, and parental consanguinity was observed in 43 (89.58%) patients. Bhalla score was available in 31 patients and "moderate and severe" score was observed in 19 (61.29%) patients. The median PICADAR score was 10 (8-11), and 34 (70.83%) patients had a high (≥ 10) PICADAR score. The ATS score was found to be 4 in 24 (50%) patients and 3 in 20 (43.75%) patients. Genetic data were available in 40 patients and mutations were found in 27 (67.5%) patients. The most common pathogenic variants were DNAH5 in 8 (20%), CCDC103 in 4 (10%), and CCDC39 in 3 (7.5%) patients. Subjects with any genetic variants may be older, have a greater frequency of parental consanguinity, higher Bhalla score, and higher ATS score (p < 0.05). DNAH5 mutation was associated with a lower likelihood of neonatal ICU stay and neonatal respiratory distress-related symptoms (p = 0.036 and 0.015, respectively).

CONCLUSIONS

Situs abnormalities may be a warning sign for the early diagnosis of PCD. Early diagnosis of PCD through genetic analysis is important for preventing chronic lung pathologies and predicting prognosis and may improve the quality of life.

The Impact of Age of Diagnosis in Children with Primary Ciliary Dyskinesia

Rationale: The typical symptoms of primary ciliary dyskinesia (PCD) manifest after birth and in early infancy, but diagnosis is often not confirmed during infancy. There is currently a lack of evidence in PCD regarding the impact of the age of the patient at the time of diagnosis on clinical outcomes. Objective: To determine whether early diagnosis of PCD is related to improved long-term outcomes. Methods: This was a retrospective study of patients diagnosed with PCD between 2000 and 2022. We divided our cohort into three groups according to the age at diagnosis: (1) early diagnosis (age <1 year), typical diagnosis (age 1-7 years), and late diagnosis (age 8-14 years). We compared various clinical long-term outcomes between the groups. Results: During the study period, 110 patients were included in the analysis, with 41 patients in the early diagnosis group, 35 in the typical diagnosis group, and 34 in the late diagnosis group. Unexplained neonatal respiratory distress and organ laterality defect were more common in the early diagnosis group, with respective rates in the early, typical, and late diagnosis groups of 80%, 53%, and 61% for neonatal respiratory distress (P = 0.045) and 64%, 50%, and 18% for laterality defect (P < 0.001). At the end of the first decade of life, patients in the early and typical-age diagnosis groups had better forced expiratory volume in 1 second compared with the late diagnosis group (93.5% and 93.1% vs. 80.2%; P = 0.002), but there was no significant change in the annual rate of decline between the groups when diagnosis had been confirmed. Patients diagnosed late had significantly higher rates of pulmonary exacerbations than those diagnosed at a typical age (1.95 vs. 0.75 per year; P < 0.01) Conclusions: Late diagnosis (age ≥8 years) was associated with lower forced expiratory volume in 1 second throughout childhood, although, once diagnosed, the annual rate of decline was not different. These findings demonstrate the negative effect of delayed diagnosis in pediatric PCD.

Association between Cystic Fibrosis and Pericardial Calcification Detected at Chest CT in Adults

Background Although pericardial calcification has been observed on chest CT scans in patients with cystic fibrosis (CF), its prevalence and characteristics have not been elucidated. Purpose To determine the prevalence and characteristics of pericardial calcification, and identify clinical variables associated with it, in adult patients with CF and to compare this prevalence with that in individuals without CF. Materials and Methods This was a retrospective, single-center case-control study including consecutive patients with CF who underwent chest CT between January 2021 and December 2022. Control group 1 included individuals without CF matched for age and sex. Control group 2 included individuals with previous Mycobacterium tuberculosis infection and no concomitant diagnosis of CF matched for sex. Control group 3 included patients with primary ciliary dyskinesia. Qualitative and quantitative evaluations of pericardial calcification were performed. The χ2 test and Fisher exact test were used for comparisons of categorical variables; the Kruskal-Wallis test and Mann-Whitney U test were used for comparisons of continuous variables. Results Of the 348 adult patients with CF (mean age, 35 years ± 13 [SD]; 193 [55%] male patients), 62 (18%) had pericardial calcification at CT. The prevalence of pericardial calcification was 1% (four of 348) in control group 1, 2% (two of 100) in control group 2, and 4% (one of 24) in control group 3 (P < .001). Pericardial calcification developed de novo in 66% (41 of 62) and progressed in 21% (13 of 62) of patients with CF. The distribution of pericardial calcification in patients with CF was most frequently multifocal (58%; 36 of 62). The median calcium score of pericardial calcification was 65 (IQR, 28-375). In patients with CF, older age, lower forced expiratory volume in 1 second, higher vitamin D level, and a higher prevalence of Burkholderia cenocepacia ET12 infection were associated with pericardial calcification. Conclusion Pericardial calcification was more prevalent in adult patients with CF than in individuals without CF and progressed over time in some patients. © RSNA, 2025 Supplemental material is available for this article.

Uplift of genetic diagnosis of rare respiratory disease using airway epithelium transcriptome analysis

Rare genetic respiratory disease has an incidence rate of more than 1:2500 live births in Northern Europe and carries significant disease burden. Early diagnosis improves outcomes, but many individuals remain without a confident genetic diagnosis. Improved and expanded molecular testing methods are required to improve genetic diagnosis rates and thereby improve clinical outcomes. Using primary ciliary dyskinesia (PCD) as an exemplar rare genetic respiratory disease, we developed a standardized method to identify pathogenic variants using whole transcriptome RNA-sequencing (RNA-seq) of nasal epithelial cells cultured at air-liquid interface (ALI). The method was optimized using cells from healthy volunteers, and people with rhino-pulmonary disease but no diagnostic indication of PCD. We validated the method using nasal epithelial cells from PCD patients with known genetic cause. We then assessed the ability of RNA-seq to identify pathogenic variants and the disease mechanism in PCD likely patients but in whom DNA genetic testing was inconclusive. The majority of 49 targeted PCD genes were optimally identified in RNA-seq data from nasal epithelial cells grown for 21 days at ALI culture. Four PCD-likely patients without a previous genetic diagnosis received a confirmed genetic diagnosis from the findings of the RNA-seq data. We demonstrate the clinical potential of RNA-seq of nasal epithelial cells to identify variants in individuals with genetically unsolved PCD. This uplifted genetic diagnosis should improve genetic counselling, enables family cascade screening, opens the door to potential personalised treatment and care approaches. This methodology could be implemented in other rare lung diseases such as cystic fibrosis.

Convergence of autism proteins at the cilium

Hundreds of high-confidence autism genes have been identified, yet the relevant etiological mechanisms remain unclear. Gene ontology analyses have repeatedly identified enrichment of proteins with annotated functions in gene expression regulation and neuronal communication. However, proteins are often pleiotropic and these annotations are inherently incomplete. Our recent autism functional genetics work has suggested that these genes may share a common mechanism at the cilium, a membrane-bound organelle critical for neurogenesis, brain patterning, and neuronal activity-all processes strongly implicated in autism. Moreover, autism commonly co-occurs with conditions that are known to involve ciliary-related pathologies, including congenital heart disease, hydrocephalus, and blindness. However, the role of autism genes at the cilium has not been systematically investigated. Here we demonstrate that autism proteins spanning disparate functional annotations converge in expression, localization, and function at cilia, and that patients with pathogenic variants in these genes have cilia-related co-occurring conditions and biomarkers of disrupted ciliary function. This degree of convergence among genes spanning diverse functional annotations strongly suggests that cilia are relevant to autism, as well as to commonly co-occurring conditions, and that this organelle should be explored further for therapeutic potential.

Progression of Otologic and Nasal Symptoms in Primary Ciliary Dyskinesia Throughout Childhood

Objective

Primary ciliary dyskinesia (PCD) is characterized by upper and lower airway disease. Multiple studies have demonstrated the progression of pulmonary disease; however, longitudinal changes in the otologic and nasal symptoms have not been well described in patients. This study defines age-related prevalence, age of onset, and age-related trends in self-reported otologic and sinonasal comorbidities in individuals with PCD.

Study Design

A prospective, longitudinal, multicenter, observational study spanning up to 12 years.

Setting

Six PCD centers in North America.

Methods

Inclusion criteria were <19 years of age and a confirmed diagnosis of PCD based on electron microscopy and/or genetics. A standardized medical history questionnaire and physical exam were completed during each study visit. Descriptive statistics were performed for the entire cohort as well as for subgroups based on ciliary ultrastructure.

Results

A total of 147 participants were followed for an average of 7.6 ± 3.2 years. Pressure equalization tubes (PETs) were placed in 80%, transient hearing loss was reported in 68%, and persistent hearing loss was reported in 30%. Hearing aids and speech therapy were utilized by 8% and 27%, respectively. PETs were placed earlier in those with inner dynein arm/microtubular disorganization defects than those with outer dynein arm defects. Participants reported chronic nasal congestion in 97%, sinusitis in 87%, and 35% underwent >1 sinus surgery.

Conclusion

There is a high prevalence of reported otologic and sinonasal morbidity among people with PCD that begins during early childhood and persists. Further analysis is indicated to evaluate differences over time among participants with varying ultrastructural defects.

Level of Evidence

Level 2.

Therapies Used by Children With Primary Ciliary Dyskinesia: A Natural History Study

INTRODUCTION

Primary ciliary dyskinesia (PCD) management has not been systematically evaluated and is largely empirical.

METHODS

Pediatric participants with PCD were enrolled in a prospective, longitudinal, multicenter, observational study. Therapies were recorded at annual visits and categorized by type. Age-related trends in prevalence of therapies were described by serial cross-sectional analyses. Generalized estimating equations analyzed covariates affecting prevalence of certain therapies and whether these covariates impacted oral antibiotic courses.

RESULTS

A total of 137 participants completed 897 visits over 13 years. All but one received ≥ 1 antibiotic courses during study participation, most often cephalosporins (74%) or amoxicillin-clavulanate (73%). Thirty-one percent reported chronic azithromycin use. Per participant, there was an average of 2.3 (SD = 2.2) oral antibiotic courses annually. The rate of reported antibiotic courses at the 6 United States sites was 2.6 times higher compared to the Canadian site (p < 0.001). As patients got older, they were more likely to report use of amoxicillin-clavulanate (p < 0.001), chronic azithromycin (p < 0.001), fluroquinolones (p < 0.001), inhaled steroids with long-acting beta-agonists (p = 0.010), and hypertonic saline (p < 0.001). Compared to outer dynein arm defects, those with inner dynein arm/microtubular disorganization defects reported increased use of chronic azithromycin (p = 0.011) and inhaled steroids (p = 0.015).

DISCUSSION

Older participants and those with inner dynein arm/microtubular disorganization defects reported more therapies likely due to disease progression and more severe phenotypes, respectively. We report that a wide range of therapies are used in PCD without disease-specific studies defining benefits and risks.

An electronic medical record retrieval system can be used to identify missed diagnosis in patients with primary ciliary dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous disease. Due to difficulty accessing diagnostic services and a lack of awareness of the syndrome, clinicians often fail to recognize the classic phenotype, leading to missed diagnoses.

METHODS

Relevant medical records were accessed through The BIG DATA QUERY AND ANALYSIS SYSTEM of Peking Union Medical College Hospital from September 1, 2012 to March 31, 2024. The search strategy included the following key terms: (bronchiectasis OR atelectasis OR recurrent cough OR recurrent expectoration OR hemoptysis) AND (sinusitis OR nasal polyps OR otitis media OR neonatal pneumonia OR neonatal respiratory distress OR ectopic pregnancy OR infertility OR artificial insemination OR assisted reproduction OR hydrocephalus OR congenital heart disease OR organ laterality defect OR right-sided heart OR semen OR consanguineous marriage). Patients were filtered according to inclusion and exclusion criteria, and those with clinical suspicion of PCD were invited for screening, which included nasal nitric oxide and whole exome sequencing.

RESULTS

A total of 874 medical records were retrieved. After filtering based on inclusion and exclusion criteria, 65 patients with clinical suspicion of PCD were identified, 21 of whom accepted our invitation to complete PCD-related screening. Among them, four were diagnosed with PCD, one was diagnosed with cystic fibrosis, and one was diagnosed with immunodeficiency-21.

CONCLUSIONS

This is the first study to use an electronic medical record retrieval system to identify missed diagnoses PCD. We believe that the methods used in this study can be extended to other rare diseases in the future.

Interpreting Variants of Uncertain Significance in PCD: Abnormal Splicing Caused by a Missense Variant of DNAAF3

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disorder characterized by dysfunction of motile cilia. While approximately 50 genes have been identified, around 25% of PCD patients remain genetically unexplained; elucidating the pathogenicity of specific variants remains a challenge.

METHODS

Whole exome sequencing (WES) and Sanger sequencing were conducted to identify potential pathogenic variants of PCD. Minigene assays were performed to evaluate the pathogenicity of variants. Transmission electron microscopy (TEM) and high-speed video analysis (HSVA) were conducted to analyze the function of cilia in respiratory epithelial cells.

RESULTS

We identified two variants of DNAAF3: c.557G>A, p.G186E in exon 5, and c.1364G>A, p.G455D at the terminal nucleotide of exon 10 in a 16-year-old male patient. Through a minigene assay, we demonstrated that the c.1364G>A variant led to a four-nucleotide skipping. The cilia in epithelial ciliary cells of the proband were almost immotile. The absence of outer dynein arms and inner dynein arms was also observed.

CONCLUSIONS

Our study identified two compound heterozygous variants of DNAAF3, a pathogenic gene for PCD, and proved that a novel missense variant c.1364G>A affects splicing. Our findings not only expanded the spectrum of mutations in the DNAAF3 gene but also highlighted the importance of investigating variants of uncertain significance (VUS) for comprehensive genetic diagnoses.

A novel homozygous mutation of CFAP300 identified in a Chinese patient with primary ciliary dyskinesia and infertility

ABSTRACT

Primary ciliary dyskinesia (PCD) is a clinically rare, genetically and phenotypically heterogeneous condition characterized by chronic respiratory tract infections, male infertility, tympanitis, and laterality abnormalities. PCD is typically resulted from variants in genes encoding assembly or structural proteins that are indispensable for the movement of motile cilia. Here, we identified a novel nonsense mutation, c.466G>T, in cilia- and flagella-associated protein 300 ( CFAP300 ) resulting in a stop codon (p.Glu156*) through whole-exome sequencing (WES). The proband had a PCD phenotype with laterality defects and immotile sperm flagella displaying a combined loss of the inner dynein arm (IDA) and outer dynein arm (ODA). Bioinformatic programs predicted that the mutation is deleterious. Successful pregnancy was achieved through intracytoplasmic sperm injection (ICSI). Our results expand the spectrum of CFAP300 variants in PCD and provide reproductive guidance for infertile couples suffering from PCD caused by them.

Upper Extremity Exercise Capacity and Muscle Oxygenation in Patients With Primary Ciliary Dyskinesia

BACKGROUND AND OBJECTIVES

Patients with primary ciliary dyskinesia (PCD) have a reduction in exercise capacity from the early stages. Although there are studies investigating these patients' lower extremity exercise capacity using various methodologies, there needs to be more research on the functional exercise capacity of the upper extremities. This study aimed to compare pulmonary function, upper extremity functional exercise capacity, muscle oxygenation, muscle strength, and physical activity level in children with PCD and controls.

METHODS

Twenty-seven children with PCD and 26 controls were included. Pulmonary function (spirometry), upper extremity functional exercise capacity (6-min pegboard and ring test (6PBRT), muscle oxygenation (Moxy device), deltoid muscle strength (dynamometer), and physical activity level (metabolic holter) were assessed.

RESULTS

Patients' FVC%, FEV1%, FEV1/FVC, PEF%, FEF25%-75%, deltoid muscle strength (%) were statistically decreased compared with controls (p < 0.05). The 6PBRT ring count, deltoid muscle oxygen saturations, and total hemoglobin levels were similar in both groups (p > 0.05).

DISCUSSION

Pulmonary function deteriorates and upper extremity muscle strength decreases in children with PCD. The upper extremity exercise capacity of these patients remains preserved. However, upper extremity resting muscle oxygen saturation is lower in children compared to healthy children. Most patients and healthy children are inactive. The upper extremity exercise capacity possibly declines due to deteriorating pulmonary function as the patients get older, which needs to be investigated routinely. Both upper-lower extremity aerobic exercise training applied consistently and physical activity counseling as part of their pulmonary rehabilitation program should be considered in children with PCD.

Asthma Among Children With Primary Ciliary Dyskinesia

This case-control study uses electronic health record data to assess the association between primary ciliary dyskinesia and asthma in children.

Investigating genotype-phenotype correlations in primary ciliary dyskinesia: a sibling cohort study

INTRODUCTION

Primary Ciliary Dyskinesia (PCD) is a complex mostly autosomal recessive disorder characterized by dysfunction of primary motor cilia, leading to multisystemic manifestations, primarily affecting the rhino-sinopulmonary system. Despite advancements in understanding its pathogenesis, genotype-phenotype correlations are not fully elucidated. Utilizing sibling cohorts offers a promising approach to investigate these genotype-phenotype correlations in PCD.

MATERIALS AND METHODS

This retrospective cohort study, conducted from 2010 to 2023 at Soroka University Medical Center in Be'er-Sheva, Israel, included patients with a confirmed diagnosis of PCD. Variables and outcomes compared include typical presenting symptoms, lung function, structural changes in chest tomography (CT), and anthropometric data.

RESULTS

Seventeen sibling patients from eight families met the inclusion criteria. At the last follow-up visit, the median age was 16 years. Genetic diagnosis revealed homozygous pathogenic variants including DNAH11, DNAAF3, DNAL1, and ZMYND10. Full concordance rates were observed for unexplained neonatal respiratory distress, chronic cough, and rhinosinusitis in patients with DNAH11 mutations. The family with the DNAAF3 mutation exhibited the lowest difference in Forced Expiratory Volume in 1 s (FEV1) Z-scores (0.48), but the highest differences in Forced Vital Capacity (FVC) Z-scores (3.39). High differences in FEV1 Z-scores were identified in the family with the DNAL1 mutation (2.06), while the lowest differences in FVC Z-scores (0.39) were observed in the same family.

DISCUSSION

High concordance rates for certain mutations in clinical features suggest potential genotype-phenotype correlations, in contrast to weak concordance in lung function. Challenges remain in establishing direct correlations between genetic mutations and clinical outcomes.

Comparison of respiratory functions, muscle strength, and physical activity among children with primary ciliary dyskinesia with and without Kartagener's syndrome and healthy controls

INTRODUCTION

Kartagener's syndrome (KS), consisting of bronchiectasis, situs inversus totalis, and sinusitis, is a subtype of primary ciliary dyskinesia (PCD). The presence of KS may affect respiratory and physical functions.

PURPOSE

This study aimed to compare respiratory functions, exercise capacity, muscle strength, and physical activity levels among children with PCD with/without KS and healthy peers.

METHODS

Fifteen patients with KS, 23 with PCD without KS, and 27 controls were compared. Pulmonary function, functional exercise capacity (6-minute walk test - 6MWT), maximal inspiratory, expiratory (MIP, MEP), and skeletal muscle strength, inspiratory muscle endurance (IME), and physical activity level were evaluated.

RESULTS

The forced expiratory volume in one second (FEV1) % (p = .009), forced expiratory flow from 25%-75% (FEF25-75%) % (p = .001), MIP (p = .034), MEP (p = .003), 6MWT distance (p = .001), and daily steps (p = .034) were significantly different among the groups. Quadriceps femoris (QF) muscle strength and IME were similar in groups (p ˃ .05). FEV1% (p = .002), FEF25-75% % (p = .001), MIP (p = .027), MEP (p = .001), and 6MWT distance (p = .003) in patients with KS; 6MWT distance (p = .003) in patients with PCD without KS was significantly lower than controls.

CONCLUSION

The presence of KS affects pulmonary function, respiratory muscle strength, and physical activity more. Exercise capacity and physical activity levels are decreased, inspiratory muscle endurance and QF muscle strength are preserved in patients with KS and PCD without KS. Kartagener's syndrome further impairs pulmonary and extrapulmonary outcomes; the reasons should be investigated, and the necessity of rehabilitation approaches that will prevent deterioration come to the fore.

Pathogenic variants in CFAP46, CFAP54, CFAP74 and CFAP221 cause primary ciliary dyskinesia with a defective C1d projection of the central apparatus

BACKGROUND

Primary ciliary dyskinesia is a rare genetic disorder caused by insufficient mucociliary clearance leading to chronic airway infections. The diagnostic guideline of the European Respiratory Society primarily recommends an evaluation of the clinical history (e.g. by the PICADAR prediction tool), nasal nitric oxide production rate measurements, high-speed videomicroscopy analysis of ciliary beating and an assessment of ciliary axonemes via transmission electron microscopy. Genetic testing can be implemented as a last step.

AIMS

In this study, we aimed to characterise primary ciliary dyskinesia with a defective C1d projection of the ciliary central apparatus and we evaluated the applicability of the European Respiratory Society diagnostic guideline to this primary ciliary dyskinesia type.

METHODS

Using a high-throughput sequencing approach of genes encoding C1d components, we identified pathogenic variants in the novel primary ciliary dyskinesia genes CFAP46 and CFAP54, and the known primary ciliary dyskinesia gene CFAP221. To fully assess this primary ciliary dyskinesia type, we also analysed individuals with pathogenic variants in CFAP74.

RESULTS

Careful evaluation revealed that C1d-defective primary ciliary dyskinesia is associated with normal situs composition, normal nasal nitric oxide production rates, normal ciliary ultrastructure by transmission electron microscopy and normal ciliary beating by high-speed videomicroscopy analysis. Despite chronic respiratory disease, PICADAR does not reliably detect this primary ciliary dyskinesia type. However, we could show by in vitro ciliary transport assays that affected individuals exhibit insufficient ciliary clearance.

CONCLUSIONS

Overall, this study extends the spectrum of primary ciliary dyskinesia genes and highlights that individuals with C1d-defective primary ciliary dyskinesia elude diagnosis when using the current diagnostic algorithm. To enable diagnosis, genetic testing should be prioritised in future diagnostic guidelines.

Lung ultrasound in children with primary ciliary dyskinesia or cystic fibrosis

INTRODUCTION

Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are respiratory conditions requiring regular chest radiography (CXR) surveillance to monitor pulmonary disease. However, CXR is insensitive for lung disease in CF and PCD. Lung ultrasound (LU) is a radiation-free alternative showing good correlation with severity of lung disease in CF but has not been studied in PCD.

METHOD

Standardized, six-zone LU studies and CXR were performed on a convenience sample of children with PCD or CF during a single visit when well. LU studies were graded using the LU scoring system, while CXR studies received a modified Chrispin-Norman score. Scores were correlated with clinical outcomes.

RESULT

Data from 30 patients with PCD and 30 with CF (median age PCD 11.5 years, CF 9.1 years) with overall mild pulmonary disease (PCD median FEV1 90% predicted, CF FEV1 100%) were analyzed. LU abnormalities appear in 11/30 (36%) patients with PCD and 9/30 (30%) with CF. Sensitivity, specificity, positive predictive, and negative predictive values for abnormal LU compared to the gold standard of CXR are 42%, 61%, 42%, and 61% in PCD, and 44%, 81%, 50%, and 77% in CF, respectively. Correlation between LU and CXR scores are poor for both diseases (PCD r = -0.1288, p = 0.4977; CF r = 0.0343, p = 0.8571), and LU score does not correlate with clinical outcomes in PCD.

CONCLUSION

The correlation of LU findings with CXR surveillance studies is poor in patients with mild disease burdens from PCD or CF, and LU scores do not correlate with clinical outcomes in PCD.

Whole genome sequencing enhances molecular diagnosis of primary ciliary dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is a genetic disorder affecting motile cilia. Most cases are inherited recessively, due to variants in >50 genes that result in abnormal or absent motile cilia. This leads to chronic upper and lower airway disease, subfertility, and laterality defects. Given overlapping clinical features and genetic heterogeneity, diagnosis can be difficult and often occurs late. Of those tested an estimated 30% of genetically screened PCD patients still lack a molecular diagnosis. A molecular diagnosis allows for appropriate clinical management including prediction of phenotypic features correlated to genotype. Here, we aimed to identify how readily a genetic diagnosis could be made using whole genome sequencing (WGS) to facilitate identification of pathogenic variants in known genes as well as novel PCD candidate genes.

METHODS

WGS was used to screen for pathogenic variants in eight patients with PCD.

RESULTS

7/8 cases had homozygous or biallelic variants in DNAH5, DNAAF4 or DNAH11 classified as pathogenic or likely pathogenic. Three identified variants were deletions, ranging from 3 to 13 kb, for which WGS identified precise breakpoints, permitting confirmation by Sanger sequencing. WGS yielded identification of a de novo variant in a novel PCD gene TUBB4B.

CONCLUSION

Here, WGS uplifted genetic diagnosis of PCD by identifying structural variants and novel modes of inheritance in new candidate genes. WGS could be an important component of the PCD diagnostic toolkit, increasing molecular diagnostic yield from current (70%) levels, and enhancing our understanding of fundamental biology of motile cilia and variants in the noncoding genome.

A 53-Year-Old Man With Recurrent Cough, Expectoration, and Fever

CASE PRESENTATION

A 53-year-old man was admitted with complaints of recurrent cough, mucopurulent phlegm, and fever for 10 days. These symptoms started in his youth, and he had experienced three or more acute attacks per year in the past 3 years. Persistent nasal obstruction was noticed. When asked for symptoms, the patient denied heartburn, wheezing, aspiration, night sweats, and weight loss. The patient was married for 30 years and had a son. He had never used tobacco products or alcohol. A family history indicated that his parents were consanguineously married, and one of his sisters died of bronchiectasis coinfection.

Recognizing clinical features of primary ciliary dyskinesia in the perinatal period

Primary ciliary dyskinesia (PCD) is a rare, motile ciliopathy inherited through mostly autosomal recessive variants that results in chronic ear, sinus, and respiratory disease. Despite neonatal respiratory distress being a common presenting symptom in term infants with PCD, the diagnosis is often delayed due to non-familiarity of neonatal caregivers with phenotypic and diagnostic features of this disease. Organ laterality defects, prenatal cerebral ventriculomegaly, and a family history of suppurative respiratory disease may occur in PCD and should prompt neonatal testing for this condition. In this review of neonatal PCD diagnoses in a large PCD clinic, prevalence and details of neonatal PCD issues are presented, highlighting the typically delayed onset of neonatal respiratory distress and lobar atelectasis on chest radiography, specific presentations in premature neonates, and responses to perinatal therapies.

Genetics of 67 patients of suspected primary ciliary dyskinesia from India

Data are limited on the genetic profile of primary ciliary dyskinesia (PCD) from developing countries. Here, we report one of the first study on genetic profile of patients with suspected PCD from India. In this prospective cross-sectional study, we enrolled 162 children with suspected PCD. We recorded clinical features, relevant laboratory tests for PCD and performed whole exome sequencing (WES). We are reporting 67 patients here who had positive variant/s on WES. We had 117 variants in 40 genes among 67 patients. Among the 108 unique variants, 33 were categorized as pathogenic or likely pathogenic (P/LP). We had nine novel variants in out cohort. The 29 definite PCD cases, diagnosed by composite reference standards, had variants in 16 genes namely LRRC6/DNAAF11 (5), DNAH5 (3), CCDC39 (3), HYDIN (3), DNAH11 (2), CCDC40 (2), CCDC65 (2) and one each DNAAF3, DNAAF2, CFAP300, RPGR, CCDC103, CCDC114, SPAG1, DNAI1, and DNAH14. To conclude, we identified 108 unique variants in 40 genes among 67 patients. The common genes involved in definite cases of PCD in Indian patients were LRRC6, DNAH5, CCDC39, and HYDIN. Our findings suggest a need to develop a separate genetic panel for PCD in the Indian population.

Primary Ciliary Dyskinesia in Adult Bronchiectasis: Data from the German Bronchiectasis Registry PROGNOSIS

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare genetic disorder caused by the malfunction of motile cilia and a specific etiology of adult bronchiectasis of unknown prevalence. A better understanding of the clinical phenotype of adults with PCD is needed to identify individuals for referral to diagnostic testing.

RESEARCH QUESTION

What is the frequency of PCD among adults with bronchiectasis; how do people with PCD differ from those with other etiologies; and which clinical characteristics are independently associated with PCD?

STUDY DESIGN AND METHODS

We investigated the proportion of PCD among the participants of the Prospective German Non-CF-Bronchiectasis Registry (PROGNOSIS) study; applied multiple imputation to account for missing data in 64 (FEV1), 58 (breathlessness), 26 (pulmonary exacerbations), and two patients (BMI), respectively; and identified predictive variables from baseline data using multivariate logistic regression analysis.

RESULTS

We consecutively recruited 1,000 patients from 38 centers across all levels of the German health care system. Overall, PCD was the fifth most common etiology of bronchiectasis in 87 patients (9%) after idiopathic, postinfective, COPD, and asthma. People with PCD showed a distinct clinical phenotype. In multivariate regression analysis, the chance of PCD being the etiology of bronchiectasis increased with the presence of upper airway disease (chronic rhinosinusitis and/or nasal polyps; adjusted OR [aOR], 6.3; 95% CI, 3.3-11.9; P < .001), age < 53 years (aOR, 5.3; 95% CI, 2.7-10.4; P < .001), radiologic involvement of any middle and lower lobe (aOR, 3.7; 95% CI, 1.3-10.8; P = .016), duration of bronchiectasis > 15 years (aOR, 3.6; 95% CI, 1.9-6.9; P < .001), and a history of Pseudomonas aeruginosa isolation from respiratory specimen (aOR, 2.4; 95% CI, 1.3-4.5; P = .007).

INTERPRETATION

Within our nationally representative cohort, PCD was a common etiology of bronchiectasis. We identified few easy-to-assess phenotypic features, which may promote awareness for PCD among adults with bronchiectasis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02574143; URL: www.

CLINICALTRIALS

gov.

The 75-Year Anniversary of the Department of Physiology and Pharmacology at Karolinska Institutet-Examples of Recent Accomplishments and Future Perspectives

Karolinska Institutet is a medical university encompassing 21 departments distributed across three departmental or campus groups. Pharmacological research has a long and successful tradition at the institute with a multitude of seminal findings in the areas of neuronal control of vasodilatation, cardiovascular pharmacology, neuropsychopharmacology, receptor pharmacology, and pharmacogenomics that resulted in, among many other recognitions, two Nobel prizes in Physiology and Medicine, one in 1970 to Ulf von Euler for his discovery of the processes involved in storage, release, and inactivation of neurotransmitters and the other in 1982 to Sune Bergström and Bengt Samuelsson for their work on prostaglandins and the discovery of leukotrienes. Pharmacology at Karolinska Institutet has over the last decade been ranked globally among the top 10 according to the QS World University Ranking. With the Department of Physiology and Pharmacology now celebrating its 75-year anniversary, we wanted to take this as an opportunity to showcase recent research achievements and how they paved the way for current activities at the department. We emphasize examples from preclinical and clinical research where the dpartment's integrative environment and robust infrastructure have successfully facilitated the translation of findings into clinical applications and patient benefits. The close collaboration between preclinical scientists and clinical researchers across various disciplines, along with a strong network of partnerships within the department and beyond, positions us to continue leading world-class pharmacological research at the Department of Physiology and Pharmacology for decades to come. SIGNIFICANCE STATEMENT: Pharmacological research at Karolinska Institutet has a long and successful history. Given the 75-year anniversary of the Department of Physiology and Pharmacology, this perspective provides an overview of recent departmental achievements and future trajectories. For these developments, interdisciplinary and intersectoral collaborations and a clear focus on result translation are key elements to continue its legacy of world-leading pharmacological research.

Delayed Diagnosis of Primary Ciliary Dyskinesia in Low-Middle-Income Countries: The Clinical Value of Nasal Nitric Oxide

Primary ciliary dyskinesia (PCD) is a rare lung disease that causes chronic oto-sino-pulmonary disease with irreversible lung damage. Several diagnostic methods exist, but electron microscopy (EM) is the most accurate tool, as it visualizes alterations in the axonemal ultrastructure; however, some patients may present a normal ciliary structure. Therefore, other diagnostic methods have been promoted, such as genetic studies or immunofluorescence of specific markers; nonetheless, they are not very accessible and expensive and even present a high level of false negatives. The quantification of nasal nitric oxide (nNO) has been a well-known tool for decades for the screening of this pathology, and recent studies have highlighted its high predictive value in the diagnosis of PCD, as it is a rapid tool in its processing, execution, and accessibility, especially in countries with limited health resources. We present the case of a patient with respiratory symptoms since childhood and extensive lung damage (cystic bronchiectasis); due to lack of access to EM or immunofluorescence, determinations of nNO were performed and found to be compatible with PCD.

Epidemiology of bronchiectasis

Bronchiectasis is a chronic respiratory disease characterised by permanent enlargement of the airways associated with cough, sputum production and a history of pulmonary exacerbations. In the past few years, incidence and prevalence of bronchiectasis have increased worldwide, possibly due to advances in imaging techniques and disease awareness, leading to increased socioeconomic burden and healthcare costs. Consistently, a mortality increase in bronchiectasis patient cohorts has been demonstrated in certain areas of the globe, with mortality rates of 16-24.8% over 4-5 years of follow-up. However, heterogeneity in epidemiological data is consistent, as reported prevalence in the general population ranges from 52.3 to more than 1000 per 100 000. Methodological flaws in the designs of available studies are likely to underestimate the proportion of people suffering from this condition worldwide and comparisons between different areas of the globe might be unreliable due to different assessment methods or local implementation of the same method in different contexts. Differences in disease severity associated with diverse geographical distribution of aetiologies, comorbidities and microbiology might explain an additional quota of heterogeneity. Finally, limited access to care in certain geographical areas is associated with both underestimation of the disease and increased severity and mortality. The aim of this review is to provide a snapshot of available real-world epidemiological data describing incidence and prevalence of bronchiectasis in the general population. Furthermore, data on mortality, healthcare burden and high-risk populations are provided. Finally, an analysis of the geographical distribution of determinants contributing to differences in bronchiectasis epidemiology is offered.

Combined approaches, including long-read sequencing, address the diagnostic challenge of HYDIN in primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD), a disorder of the motile cilia, is now recognised as an underdiagnosed cause of bronchiectasis. Accurate PCD diagnosis comprises clinical assessment, analysis of cilia and the identification of biallelic variants in one of 50 known PCD-related genes, including HYDIN. HYDIN-related PCD is underdiagnosed due to the presence of a pseudogene, HYDIN2, with 98% sequence homology to HYDIN. This presents a significant challenge for Short-Read Next Generation Sequencing (SR-NGS) and analysis, and many diagnostic PCD gene panels do not include HYDIN. We have used a combined approach of SR-NGS with bioinformatic masking of HYDIN2, and state-of-the-art long-read Nanopore sequencing (LR_NGS), together with analysis of respiratory cilia including transmission electron microscopy and immunofluorescence to address the underdiagnosis of HYDIN as a cause of PCD. Bioinformatic masking of HYDIN2 after SR-NGS facilitated the detection of biallelic HYDIN variants in 15 of 437 families, but compromised the detection of copy number variants. Supplementing testing with LR-NGS detected HYDIN deletions in 2 families, where SR-NGS had detected a single heterozygous HYDIN variant. LR-NGS was also able to confirm true homozygosity in 2 families when parental testing was not possible. Utilising a combined genomic diagnostic approach, biallelic HYDIN variants were detected in 17 families from 242 genetically confirmed PCD cases, comprising 7% of our PCD cohort. This represents the largest reported HYDIN cohort to date and highlights previous underdiagnosis of HYDIN-associated PCD. Moreover this provides further evidence for the utility of LR-NGS in diagnostic testing, particularly for regions of high genomic complexity.

Priorities and barriers for research related to primary ciliary dyskinesia

Background

Despite advances in primary ciliary dyskinesia (PCD) research, many questions remain; diagnosis is complex and no disease-specific therapies exist. Using a mixed-methods approach, we aimed to identify priorities for clinical and epidemiological research and explore barriers to research.

Methods

To obtain rich, relevant, diverse data, we performed in-depth semi-structured interviews with PCD specialists selected using purposive sampling. We transcribed, coded and analysed interview data using thematic analysis. Based on interview themes that we identified, we developed an anonymous survey and circulated it widely through the BEAT-PCD network.

Results

We interviewed 28 participants from 15 countries across different disciplines and expertise levels. The main themes identified as priorities for PCD research were improving diagnosis; understanding prevalence and disease course; phenotypic variability; disease monitoring; treatment strategies; clinical trial end-points; and poorly researched areas. In total, 136 participants (49% paediatric pulmonologists) from 36 countries completed the survey. Most commonly reported barriers for research were low awareness about PCD and difficulties securing funding - in more than one-third of cases, participants reported undertaking predominantly unfunded research. Research questions ranked highest included priorities related to further improving diagnosis, treating PCD, managing upper and lower airway problems, and studying clinical variability and disease prognosis.

Conclusion

We need to overcome barriers of limited funding and low awareness and promote collaborations between centres, disciplines, experts and patients to address identified PCD priorities effectively. Our results contribute to the ongoing efforts of guiding the use of existing limited research resources and setting up a roadmap for future research activities.

Respiratory Aspects of Primary Ciliary Dyskinesia

This review article explores the respiratory aspects of primary ciliary dyskinesia (PCD), a rare, heterogenous, genetic disorder characterized by impaired motile ciliary function. It discusses the clinical diagnosis and management strategies for PCD-related respiratory disease, including chronic sinusitis, otitis media with effusion, recurrent pneumonia, and bronchiectasis. The review emphasizes the need for a multidisciplinary approach to optimize care and clinical trials to improve outcomes in individuals with PCD, highlighting the importance of accurate diagnosis.

Characterization of pathogenic genetic variants in Russian patients with primary ciliary dyskinesia using gene panel sequencing and transcript analysis

BACKGROUND

Primary ciliary dyskinesia (PCD) is a group of rare genetically heterogeneous disorders caused by defective cilia and flagella motility. The clinical phenotype of PCD patients commonly includes chronic oto-sino-pulmonary disease, infertility, and, in about half of cases, laterality defects due to randomization of left-right body asymmetry. To date, pathogenic variants in more than 50 genes responsible for motile cilia structure and assembly have been reported in such patients. While multiple population-specific mutations have been described in PCD cohorts from different countries, the data on genetic spectrum of PCD in Russian population are still extremely limited.

RESULTS

The present study provides a comprehensive clinical and genetic characterization of 21 Russian families with PCD living in various country regions. Anomalies of ciliary beating in patients` respiratory epithelial cells were confirmed by high-speed video microscopy. In the most cases, custom-designed panel sequencing allowed to uncover causative variants in well-known or rarely mentioned PCD-related genes, including DNAH5, DNAH11, CFAP300, LRRC6, ZMYND10, CCDC103, HYDIN, ODAD4, DNAL1, and OFD1. The variations comprised common mutations, as well as novel genetic variants, some of which probably specific for Russian patients. Additional targeted analysis of mRNA transcripts from ciliated cells enabled us to specify functional effects of newly identified genetic variants in DNAH5 (c.2052+3G>T, c.3599-2A>G), HYDIN (c.10949-2A>G, c.1797C>G), and ZMYND10 (c.510+1G>C) on splicing process. In particular, the splice site variant c.2052+3G>T, detected in four unrelated families, resulted in skipping of exon 14 in DNAH5 transcripts and, according to haplotype analysis of affected probands, was proposed as an ancestral founder mutation in Udmurt population.

CONCLUSIONS

The reported data provide a vital insight into genetic background of primary ciliary dyskinesia in the Russian population. The findings clearly illustrate the utility of gene panel sequencing coupled with transcriptional analysis in identification and clinical interpretation of novel genetic variants.

Development and Initial Characterization of Pigs with DNAI1 Mutations and Primary Ciliary Dyskinesia

Mutations in more than 50 different genes cause primary ciliary dyskinesia (PCD) by disrupting the activity of motile cilia that facilitate mucociliary transport (MCT). Knowledge of PCD has come from studies identifying disease-causing mutations, characterizing structural cilia abnormalities, finding genotype-phenotype relationships, and studying the cell biology of cilia. Despite these important findings, we still lack effective treatments and people with PCD have significant pulmonary impairment. As with many other diseases, a better understanding of pathogenic mechanisms may lead to effective treatments. To pursue disease mechanisms, we used CRISPR-Cas9 to develop a PCD pig with a disrupted DNAI1 gene. PCD pig airway cilia lacked the outer dynein arm and had impaired beating. MCT was impaired under both baseline conditions and after cholinergic stimulation in PCD pigs. Neonatal PCD pigs developed neonatal respiratory distress with evidence of atelectasis, air trapping, and airway mucus obstruction. Despite airway mucus accumulation, lung bacterial counts were similar between neonatal wild-type and PCD pigs. Sinonasal disease was present in all neonatal PCD pigs. Older PCD pigs developed worsening airway mucus obstruction, inflammation, and bacterial infection. This pig model closely mimics the disease phenotype seen in people with PCD and can be used to better understand the pathophysiology of PCD airway disease.

Evaluation of Open-Source Ciliary Analysis Software in Primary Ciliary Dyskinesia: A Comparative Assessment

Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder characterized by alterations in motile cilia function. The diagnosis of PCD is challenging due to the lack of standardized methods in clinical practice. High-speed video microscopy analysis (HSVA) directly evaluates ciliary beat frequency (CBF) in PCD. Recently, open-source ciliary analysis software applications have shown promise in measuring CBF accurately. However, there is limited knowledge about the performance of different software applications, creating a gap in understanding their comparative effectiveness in measuring CBF in PCD. We compared two open-source software applications, CiliarMove (v219) and Cilialyzer (v1.2.1-b3098cb), against the manual count method. We used high-speed videos of nasal ciliary brush samples from PCD RSPH4A-positive (PCD (RSPH4A)) patients and healthy controls. All three methods showed lower median CBF values for patients with PCD (RSPH4A) than in healthy controls. CiliarMove and Cilialyzer identified lower CBF in patients with PCD (RSPH4A), similarly to the manual count. Cilialyzer, CiliarMove, and manual count methods demonstrated statistical significance (p-value < 0.0001) in the difference of median CBF values between patients with PCD (RSPH4A) and healthy controls. Correlation coefficients between the manual count values against both software methods demonstrated positive linear relationships. These findings support the utility of open-source software-based analysis tools. Further studies are needed to validate these findings with other genetic variants and identify the optimal software for accurate CBF measurement in patients with PCD.

Analyses of 1236 genotyped primary ciliary dyskinesia individuals identify regional clusters of distinct DNA variants and significant genotype-phenotype correlations

BACKGROUND

Primary ciliary dyskinesia (PCD) represents a group of rare hereditary disorders characterised by deficient ciliary airway clearance that can be associated with laterality defects. We aimed to describe the underlying gene defects, geographical differences in genotypes and their relationship to diagnostic findings and clinical phenotypes.

METHODS

Genetic variants and clinical findings (age, sex, body mass index, laterality defects, forced expiratory volume in 1 s (FEV1)) were collected from 19 countries using the European Reference Network's ERN-LUNG international PCD Registry. Genetic data were evaluated according to American College of Medical Genetics and Genomics guidelines. We assessed regional distribution of implicated genes and genetic variants as well as genotype correlations with laterality defects and FEV1.

RESULTS

The study included 1236 individuals carrying 908 distinct pathogenic DNA variants in 46 PCD genes. We found considerable variation in the distribution of PCD genotypes across countries due to the presence of distinct founder variants. The prevalence of PCD genotypes associated with pathognomonic ultrastructural defects (mean 72%, range 47-100%) and laterality defects (mean 42%, range 28-69%) varied widely among countries. The prevalence of laterality defects was significantly lower in PCD individuals without pathognomonic ciliary ultrastructure defects (18%). The PCD cohort had a reduced median FEV1 z-score (-1.66). Median FEV1 z-scores were significantly lower in CCNO (-3.26), CCDC39 (-2.49) and CCDC40 (-2.96) variant groups, while the FEV1 z-score reductions were significantly milder in DNAH11 (-0.83) and ODAD1 (-0.85) variant groups compared to the whole PCD cohort.

CONCLUSION

This unprecedented multinational dataset of DNA variants and information on their distribution across countries facilitates interpretation of the genetic epidemiology of PCD and indicates that the genetic variant can predict diagnostic and phenotypic features such as the course of lung function.

Transcriptional analysis of primary ciliary dyskinesia airway cells reveals a dedicated cilia glutathione pathway

Primary ciliary dyskinesia (PCD) is a genetic condition that results in dysmotile cilia. The repercussions of cilia dysmotility and gene variants on the multiciliated cell remain poorly understood. We used single-cell RNA-Seq, proteomics, and advanced microscopy to compare primary culture epithelial cells from patients with PCD, their heterozygous mothers, and healthy individuals, and we induced pluripotent stem cells (iPScs) generated from a patient with PCD. Transcriptomic analysis revealed unique signatures in PCD airway cells compared with their mothers' cells and the cells of healthy individuals. Gene expression in heterozygous mothers' cells diverged from both control and PCD cells, marked by increased inflammatory and cellular stress signatures. Primary and iPS-derived PCD multiciliated cells had increased expression of glutathione-S-transferases GSTA2 and GSTA1, as well as NRF2 target genes, accompanied by elevated levels of reactive oxygen species (ROS). Immunogold labeling in human cilia and proteomic analysis of the ciliated organism Chlamydomonas reinhardtii demonstrated that GSTA2 localizes to motile cilia. Loss of human GSTA2 and C. reinhardtii GSTA resulted in slowed cilia motility, pointing to local cilia regulatory roles. Our findings identify cellular responses unique to PCD variants and independent of environmental stress and uncover a dedicated ciliary GSTA2 pathway essential for normal motility that may be a therapeutic target.