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

A novel splicing mutation DNAH5 c.13,338 + 5G > C is involved in the pathogenesis of primary ciliary dyskinesia in a family with primary familial brain calcification

BACKGROUND

Primary ciliary dyskinesia (PCD) is an autosomal recessive hereditary disease characterized by recurrent respiratory infections. In clinical manifestations, DNAH5 (NM_001361.3) is one of the recessive pathogenic genes. Primary familial brain calcification (PFBC) is a neurodegenerative disease characterized by bilateral calcification in the basal ganglia and other brain regions. PFBC can be inherited in an autosomal dominant or recessive manner. A family with PCD caused by a DNAH5 compound heterozygous variant and PFBC caused by a MYORG homozygous variant was analyzed.

METHODS

In this study, we recruited three generations of Han families with primary ciliary dyskinesia combined with primary familial brain calcification. Their clinical phenotype data were collected, next-generation sequencing was performed to screen suspected pathogenic mutations in the proband and segregation analysis of families was carried out by Sanger sequencing. The mutant and wild-type plasmids were constructed and transfected into HEK293T cells instantaneously, and splicing patterns were detected by Minigene splicing assay. The structure and function of mutations were analyzed by bioinformatics analysis.

RESULTS

The clinical phenotypes of the proband (II10) and his sister (II8) were bronchiectasis, recurrent pulmonary infection, multiple symmetric calcifications of bilateral globus pallidus and cerebellar dentate nucleus, paranasal sinusitis in the whole group, and electron microscopy of bronchial mucosa showed that the ciliary axoneme was defective. There was also total visceral inversion in II10 but not in II8. A novel splice variant C.13,338 + 5G > C and a frameshift variant C.4314delT (p. Asn1438lysfs *10) were found in the DNAH5 gene in proband (II10) and II8. c.347_348dupCTGGCCTTCCGC homozygous insertion variation was found in the MYORG of the proband. The two pathogenic genes were co-segregated in the family. Minigene showed that DNAH5 c.13,338 + 5G > C has two abnormal splicing modes: One is that part of the intron bases where the mutation site located is translated, resulting in early translation termination of DNAH5; The other is the mutation resulting in the deletion of exon76.

CONCLUSIONS

The newly identified DNAH5 splicing mutation c.13,338 + 5G > C is involved in the pathogenesis of PCD in the family, and forms a compound heterozygote with the pathogenic variant DNAH5 c.4314delT lead to the pathogenesis of PCD.

Estimates of primary ciliary dyskinesia prevalence: a scoping review

Background

Primary ciliary dyskinesia (PCD) is a rare multisystem genetic disease caused by dysfunctional motile cilia. Despite PCD being the second most common inherited airway disease after cystic fibrosis, PCD continues to be under-recognised globally owing to nonspecific clinical features and the lack of a gold standard diagnostic test. Commonly repeated prevalence estimates range from one in 10 000 to one in 20 000, based on regional epidemiological studies with known limitations. The purpose of this scoping review was to appraise the PCD literature, to determine the best available global PCD prevalence estimate and to inform the reader about the potential unmet health service needs in PCD. The primary objective of the present study was to systematically review the literature about PCD prevalence estimates.

Methods

A scoping review was conducted following the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for scoping reviews (PRISMA-ScR) methodology. Included studies estimated PCD prevalence and used cohort, clinical or genomic data. Case reports, conference abstracts, review articles, animal studies or non-English articles were excluded.

Results

A literature review identified 3484 unique abstracts; 34 underwent full-text review and eight met the inclusion/exclusion criteria. Seven articles were based on epidemiological studies of specific geographical regions and provided prevalence estimates that ranged from approximately one to 44.1 in 100 000. Only one study estimated global prevalence, using two large genomic databases, and calculated it to be ∼13.2 in 100 000 (based on pathogenic variants in 29 disease-causing genes).

Conclusions

A population-based genomic approach for estimating global prevalence has found that PCD is much more prevalent than previously cited in the literature. This highlights the potential unmet health service needs of people living with PCD.

Bronchiectasis

Non-cystic fibrosis bronchiectasis, a condition that remains relatively underrecognized, has garnered increasing research focus in recent years. This scientific interest has catalyzed advancements in diagnostic methodologies, enabling comprehensive clinical and molecular profiling. Such progress facilitates the development of personalized treatment strategies, marking a significant step toward precision medicine for these patients. Bronchiectasis poses significant diagnostic challenges in both clinical settings and research studies. While computed tomography (CT) remains the gold standard for diagnosis, novel alternatives are emerging. These include artificial intelligence-powered algorithms, ultra-low dose chest CT, and magnetic resonance imaging (MRI) techniques, all of which are becoming recognized as feasible diagnostic tools. The precision medicine paradigm calls for refined characterization of bronchiectasis patients by analyzing their inflammatory and molecular profiles. Research into the underlying mechanisms of inflammation and the evaluation of biomarkers such as neutrophil elastase, mucins, and antimicrobial peptides have led to the identification of distinct patient endotypes. These endotypes present variable clinical outcomes, necessitating tailored therapeutic interventions. Among these, eosinophilic bronchiectasis is notable for its prevalence and specific prognostic factors, calling for careful consideration of treatable traits. A deeper understanding of the microbiome's influence on the pathogenesis and progression of bronchiectasis has inspired a holistic approach, which considers the multibiome as an interconnected microbial network rather than treating pathogens as solitary entities. Interactome analysis therefore becomes a vital tool for pinpointing alterations during both stable phases and exacerbations. This array of innovative approaches has revolutionized the personalization of treatments, incorporating therapies such as inhaled mannitol or ARINA-1, brensocatib for anti-inflammatory purposes, and inhaled corticosteroids specifically for patients with eosinophilic bronchiectasis.

The Coronavirus Disease 2019 Pandemic and Time to Diagnosis for Childhood Pulmonary Diseases: Outcomes of a Tertiary Care Center

Coronavirus disease 2019 pandemic caused many changes in the social behaviors of individuals and the provision of health systems. Many studies revealed reductions in the number of diagnoses and delays in diagnosis time during the pandemic. This study aimed to evaluate the effect of the pandemic on the time to diagnosis of major diseases of pediatric pulmonology. Newly diagnosed patients with cystic fibrosis (CF), childhood interstitial lung disease (chILD), tuberculosis (TB), and primary ciliary dyskinesia (PCD) were grouped into pandemic (group 1) and 2 consecutive pre-pandemic periods divided into equal intervals (groups 2 and 3). For each disease group, the time to diagnosis was compared between the specified periods. A total number of patients were 171 in this study. In the CF group, there was no statistically difference in time to diagnosis between periods. In the chILD group, there was a statistically significant difference in time to diagnosis (P = .036) between groups (group 1: 2 months, group 2: 4 months and group 3: 10.5 months) that was not originated from pandemic period. In TB group there was no statistically significant difference between groups. In the PCD group, the impact of the pandemic on the time to diagnosis could not be clarified because the time interval to diagnosis (minimum: 2 years, maximum: 16 years) exceeded the studied periods (21 months). In our study, no effect found between the pandemic and age at diagnosis or time to diagnosis in patients with PCD, chILD, CF, and TB at our center.

Primary Ciliary Dyskinesia: A Clinical Review

Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous, motile ciliopathy, characterized by neonatal respiratory distress, recurrent upper and lower respiratory tract infections, subfertility, and laterality defects. Diagnosis relies on a combination of tests for confirmation, including nasal nitric oxide (nNO) measurements, high-speed videomicroscopy analysis (HSVMA), immunofluorescent staining, axonemal ultrastructure analysis via transmission electron microscopy (TEM), and genetic testing. Notably, there is no single gold standard confirmatory or exclusionary test. Currently, 54 causative genes involved in cilia assembly, structure, and function have been linked to PCD; this rare disease has a spectrum of clinical manifestations and emerging genotype-phenotype relationships. In this review, we provide an overview of the structure and function of motile cilia, the emerging genetics and pathophysiology of this rare disease, as well as clinical features associated with motile ciliopathies, novel diagnostic tools, and updates on genotype-phenotype relationships in PCD.

Kartagener's Syndrome: A Case Series

Kartagener's syndrome is an uncommon autosomal recessive ciliary dyskinesia. It combines a triad comprised of bronchiectasis, chronic sinusitis, and situs inversus. This work aims to describe the clinical and paraclinical aspects of primary ciliary dyskinesia using Kartagener's syndrome as a model and to highlight the difficulties of confirming the diagnosis in our context. We report four observations (three boys and one girl with an average age of 10 years) of Kartagener's syndrome collected in the department of pediatric pneumo-allergology. Chronic bronchorrhea and otorhinolaryngological manifestations were found in all cases. Signs of neonatal respiratory distress syndrome were found in only one case. One child had dysmorphic facial features suggestive of Noonan's syndrome and conductive hearing loss. Digital hippocratism was found in half of the cases, along with pulmonary crackles and heart sounds perceived on the right. A chest CT scan showed bronchiectasis in all patients and necrotic adenopathy suggestive of tuberculosis in one case. Sinus imaging showed an appearance of pansinusitis. All children had abdominal situs inversus with dextrocardia. They had received antibiotic therapy with amoxicillin-clavulanic acid associated with respiratory physiotherapy. The girl had benefited from a right lobectomy with a follow-up of 18 months and a good evolution. In light of these four observations, Kartagener's syndrome is a rare disease but can be compatible with normal life if the treatment is done early. However, in our context, the difficulty of confirming the diagnosis explains its delay with the risk of progression of pulmonary lesions.

Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a rare, genetic disease characterized by dysfunctional motile cilia and abnormal mucociliary clearance, resulting in chronic sino-oto-pulmonary disease, neonatal respiratory distress, subfertility, and organ laterality defects. Over the past 2 decades, research and international collaborations have led to an improved understanding of disease prevalence, classic and variable phenotypes, novel diagnostics, genotype-phenotype correlations, long term morbidity, and innovative therapeutics. However, PCD is often underrecognized in clinical settings and the recent analyses of genetic databases suggest that only a fraction of these patients are being accurately diagnosed. Knowledge of significant advancements, from pathophysiology to the expanded range of clinical manifestations, will have important clinical impacts. These may include increasing disease recognition, improving diagnostic testing and management, and establishing an adequate pool of affected patients to enroll in upcoming clinical therapeutic trials. The objective of this state-of-the-art review is for readers to gain a greater understanding of the clinical spectrum of motile ciliopathies, cutting-edge diagnostic practices, emerging genotype-phenotype associations, and currently accepted management of people with PCD.

Genetic Spectrum and Clinical Characteristics of Patients with Primary Ciliary Dyskinesia: a Belgian Single Center Study

PURPOSE

We aimed to examine the correlation between clinical characteristics and the pathogenic gene variants in patients with Primary Ciliary Dyskinesia (PCD).

METHODS

We conducted a retrospective single-center study in patients with PCD followed at the University Hospitals Leuven. We included patients with genetically confirmed PCD and described their genotype, data from ultrastructural ciliary evaluation and clinical characteristics. Genotype/phenotype correlations were studied in patients with the most frequently involved genes.

RESULTS

We enrolled 74 patients with a median age of 25.58 years. The most frequently involved genes were DNAH11 (n = 23) and DNAH5 (n = 19). The most frequent types of pathogenic variants were missense (n = 42) and frameshift variants (n = 36) and most patients had compound heterozygous variants (n = 44). Ciliary ultrastructure (p < 0.001), situs (p = 0.015) and age at diagnosis (median 9.50 vs 4.71 years, p = 0.037) differed between DNAH11 and DNAH5. When correcting for situs this difference in age at diagnosis was no longer significant (p = 0.973). Patients with situs inversus were diagnosed earlier (p = 0.031). Respiratory tract microbiology (p = 0.161), lung function (cross-sectional, p = 0.829 and longitudinal, p = 0.329) and chest CT abnormalities (p = 0.202) were not significantly different between DNAH11 and DNAH5 variants.

CONCLUSION

This study suggests a genotype-phenotype correlation for some of the evaluated clinical characteristics of the two most frequently involved genes in this study, namely DNAH11 and DNAH5.

Practical guide for the diagnosis and management of primary ciliary dyskinesia

OBJECTIVE

Primary ciliary dyskinesia (PCD) is a relatively rare genetic disorder that affects approximately 1 in 20,000 people. Approximately 50 genes are currently known to cause PCD. In light of differences in causative genes and the medical system in Japan compared with other countries, a practical guide was needed for the diagnosis and management of Japanese PCD patients.

METHODS

An ad hoc academic committee was organized under the Japanese Rhinologic Society to produce a practical guide, with participation by committee members from several academic societies in Japan. The practical guide including diagnostic criteria for PCD was approved by the Japanese Rhinologic Society, Japanese Society of Otolaryngology-Head and Neck Surgery, Japanese Respiratory Society, and Japanese Society of Pediatric Pulmonology.

RESULTS

The diagnostic criteria for PCD consist of six clinical features, six laboratory findings, differential diagnosis, and genetic testing. The diagnosis of PCD is categorized as definite, probable, or possible PCD based on a combination of the four items above. Diagnosis of definite PCD requires exclusion of cystic fibrosis and primary immunodeficiency, at least one of the six clinical features, and a positive result for at least one of the following: (1) Class 1 defect on electron microscopy of cilia, (2) pathogenic or likely pathogenic variants in a PCD-related gene, or (3) impairment of ciliary motility that can be repaired by correcting the causative gene variants in iPS cells established from the patient's peripheral blood cells.

CONCLUSION

This practical guide provides clinicians with useful information for the diagnosis and management of PCD in Japan.

[Primary ciliary dyskinesia]

Primary ciliary dyskinesia (PCD) is a rare genetic disorder with a variable clinical phenotype that is accompanied by reduced motility of the cilia in the respiratory tract and numerous other organs. This leads to various characteristic symptoms and disease manifestations, primarily affecting the lungs (chronic persistent productive cough, bronchiectasis), the nose and paranasal sinuses (chronic persistent rhinitis or rhinosinusitis) as well as the middle ear (chronic otitis media, middle ear effusion). Moreover, PCD is associated with impaired fertility or lateralization defects (situs anomalies, congenital heart defects). The diagnostics of PCD are complex and require a combination of several sophisticated instrument-based diagnostic procedures. Through thorough history taking and evaluation, suspected cases can be comparatively well identified based on typical clinical features and referred to further diagnostics. In recent years, molecular genetic analysis through panel diagnostics or whole exome and whole genome sequencing, has gained in importance as this enables affected individuals to participate in disease-specific and genotype-specific clinical trials. Although the current treatment is purely symptomatic, the earliest possible diagnosis is crucial for connecting patients to specialized PCD centers, which can have a significant impact on the clinical course of the affected individuals.

A novel mutation in GAS8 gene associated with chronic rhinosinusitis with nasal polyposis in a case of primary ciliary dyskinesia: a case report

Background

Primary ciliary dyskinesia (PCD) is considered a rare cause of chronic rhinosinusitis with nasal polyposis (CRSwNP), which is reported in 6% of children with PCD. The forms of PCD associated with the variants of the GAS8 gene identified so far seem to be linked to recurrent respiratory infections (sinusitis, otitis, and bronchiectasis) without situs inversus.

Case presentation

We report a case of an 11-year-old girl with recurrent otitis media, productive cough, and chronic rhinosinusitis with nasal polyposis with homozygosity for a novel nonsense mutation in the GAS8.

Conclusion

Children with CRSwNP should be treated in a multidisciplinary manner (ENT, pulmonologist, allergist, pathologist, pediatrician, and geneticist) because nasal polyposis often hides etiologies that must be recognized.

FOXJ1 Variants Causing Primary Ciliary Dyskinesia with Hydrocephalus: A Case Report from Japan

Primary ciliary dyskinesia (PCD) is a genetic disease characterized by motile cilia dysfunction, mostly inherited in an autosomal recessive or X-linked manner. We herein report a 29-year-old woman with PCD caused by a heterozygous frameshift mutation due to a single nucleotide deletion in exon 3 of FOXJ1. Heterozygous de novo mutations in FOXJ1 have been reported as an autosomal-dominant cause of PCD. The patient had situs inversus, congenital heart disease, infertility, and hydrocephalus. However, the nasal nitric oxide level was normal. Long-term macrolide therapy was remarkably effective. This is the first case report of PCD caused by a FOXJ1 variant in Japan.

IFT27 regulates the long-term maintenance of photoreceptor outer segments in zebrafish

Approximately a quarter of Retinitis Pigmentosa (RP) is caused by mutations in transport-related genes in cilia. IFT27 (Intraflagellar Transport 27), a core component of the ciliary intraflagellar transport (IFT) system, has been implicated as a significant pathogenic gene in RP. The pathogenic mechanisms and subsequent pathology related to IFT27 mutations in RP are largely obscure. Here, we utilized TALEN technology to create an ift27 knockout (ift27-/-) zebrafish model. Electroretinography (ERG) detection showed impaired vision in this model. Histopathological examinations disclosed that ift27 mutations cause progressive degeneration of photoreceptors in zebrafish, and this degeneration was late-onset. Immunofluorescence labeling of outer segments showed that rods degenerated before cones, aligning with the conventional characterization of RP. In cultured human retinal pigment epithelial cells, we found that IFT27 was involved in maintaining ciliary morphology. Furthermore, decreased IFT27 expression resulted in the inhibition of the Hedgehog (Hh) signaling pathway, including decreased expression of key factors in the Hh pathway and abnormal localization of the ciliary mediator Gli2. In summary, we generated an ift27-/- zebrafish line with retinal degeneration which mimicked the symptoms of RP patients, highlighting IFT27's integral role in the long-term maintenance of cilia via the Hh signaling pathway. This work may furnish new insights into the treatment or delay of RP caused by IFT27 mutations.

Situs Inversus Totalis in a Newborn With Primary Ciliary Dyskinesia

Respiratory distress in the newborn is associated with numerous etiologies, some common and some rare. When respiratory distress is accompanied by laterality defects, namely, situs inversus (SI), the index of suspicion for comorbid primary ciliary dyskinesia (PCD) should be raised. Primary ciliary dyskinesia is characterized by ciliary dysmotility and the accumulation of thick secretions in the airways that obstruct air and gas exchange. Neonatal clinicians should know that while PCD is definitively diagnosed in infancy or early childhood, findings suspicious for PCD should be communicated to primary care providers at discharge from the hospital to facilitate timely subspecialty involvement, diagnosis, and treatment. This article will present a case report of a term newborn with SI totalis who was later diagnosed with PCD. We will discuss epidemiology, pathophysiology, clinical manifestations, and diagnostics, followed by management strategies. Additionally, we discuss the outpatient needs and lifespan implications.

Comparing region of interest selection and whole-field analysis for measurement of ciliary beat frequency in high-speed video analysis

BACKGROUND

Ciliary beat frequency (CBF) is crucial in mucociliary clearance. High-speed video analysis (HSVA) is commonly used to measure CBF but lacks standardization. We compared visual observation and computer-assisted calculation using fast Fourier transformation (FFT) in freshly collected bronchial ciliary epithelial cells and cultured cells.

METHODS

Bronchial epithelial cells were obtained from 12 patients who required bronchoscopic examination. Eighty-five videos of ciliary movement of freshly collected and cultured cells were recorded and used to calculate CBF using manual observation, region of interest (ROI) selection, and whole-field analysis.

RESULTS

CBF measured by the ROI selection method strongly correlated with that measured using manual observation, especially in freshly collected cells. However, 27.8% of the manual observation method values were doubled in the ROI selection method, probably because a round trip of cilia was calculated as two cycles and needed to be corrected to 1/2 value. Upon increasing the number of ROIs, the results of the ROI selection method came closer to that of WFA.

CONCLUSIONS

Computer-assisted calculation using FFT can aid in measuring CBF; however, current methods require visual confirmation. Further automated evaluation techniques are needed to establish more standardized and generalized CBF measurement methods using HSVA.

Situs Ambiguus Is Associated With Adverse Clinical Outcomes in Children With Primary Ciliary Dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare disorder of motile cilia associated with situs abnormalities. At least 12% of patients with PCD have situs ambiguus (SA), including organ laterality defects falling outside normal arrangement (situs solitus [SS]) or mirror image inversion (situs inversus totalis [SIT]).

RESEARCH QUESTION

Do patients with PCD and SA achieve worse clinical outcomes compared with those with SS or SIT?

STUDY DESIGN AND METHODS

This cross-sectional, multicenter study evaluated participants aged 21 years or younger with PCD. Participants were classified as having SA, including heterotaxy, or not having SA (SS or SIT). Markers of disease severity were compared between situs groups, adjusting for age at enrollment and severe CCDC39 or CCDC40 genotype, using generalized linear models and logistic and Poisson regression.

RESULTS

In 397 participants with PCD (mean age, 8.4 years; range, 0.1-21), 42 patients were classified as having SA, including 16 patients (38%) with complex cardiovascular malformations or atrial isomerism, 13 patients (31%) with simple CVM, and 13 patients (31%) without cardiovascular malformations. Of these, 15 patients (36%) underwent cardiac surgery, 24 patients (57%) showed an anatomic spleen abnormality, and seven patients (17%) showed both. The remaining 355 participants did not have SA, including 152 with SIT and 203 with SS. Overall, 70 participants (17%) harbored the severe CCDC39 or CCDC40 genotype. Compared with participants without SA, those with SA showed lower median BMI z scores (P = .03), lower FVC z scores (P = .01), and more hospitalizations and IV antibiotic courses for acute respiratory infections during the 5 years before enrollment (P < .01). Participants with cardiovascular malformations requiring surgery or with anatomic spleen abnormalities showed lower median BMI z scores and more hospitalizations and IV therapies for respiratory illnesses compared with participants without SA.

INTERPRETATION

Children with PCD and SA achieve worse nutritional and pulmonary outcomes with more hospitalizations for acute respiratory illnesses than those with SS or SIT combined. Poor nutrition and increased hospitalizations for respiratory infections in participants with SA and PCD are associated with cardiovascular malformations requiring cardiac surgery, splenic anomalies, or both.

TRIAL REGISTRY

ClinicalTrials.gov; Nos.: NCT02389049 and NCT00323167; URL: www.

CLINICALTRIALS

gov.

The utility of nasal nitric oxide in the diagnostic evaluation of primary ciliary dyskinesia

BACKGROUND

There is no gold-standard test for primary ciliary dyskinesia (PCD), rather American Thoracic Society guidelines recommend starting with nasal nitric oxide (nNO) in children ≥5 years old and confirming the diagnosis with genetic testing or ciliary biopsy with transmission electron microscopy (TEM). These guidelines have not been studied in a clinical setting. We present a case series describing the PCD diagnostic process at our pediatric PCD center.

METHODS

Diagnostic data from 131 patients undergoing PCD consultation were reviewed.

RESULTS

In all participants ≥ 5 years old and who completed nNO using resistor methodology, the first diagnostic test performed was nNO in 77% (73/95), genetic testing in 14% (13/95), and TEM in <1% (9/95). nNO was the only diagnostic test performed in 75% (55/73) of participants who completed nNO first. Seventy-five percent (55/73) had a single above the cutoff nNO value and PCD was determined to be unlikely in 91% (50/55) without performing additional confirmatory testing. Eleven percent (8/73) had multiple below the cutoff nNO values, with 38% (3/8) being diagnosed with PCD by confirmatory testing and 50% (4/8) with negative confirmatory testing, but being managed as PCD. The genetic testing positivity rate was 50% in participants who completed nNO first and 8% when genetic testing was completed first.

CONCLUSION

nNO is useful in three situations: an initial above the cutoff nNO value makes PCD unlikely and prevents additional confirmatory testing, repetitively below the cutoff nNO values without positive confirmatory testing suggests a probable PCD diagnosis and the yield of genetic testing is higher when nNO is performed first.

Stepwise genetic approach for the diagnosis of primary ciliary dyskinesia in highly consanguineous populations

BACKGROUND

The American Thoracic Society guidelines for the diagnosis of primary ciliary dyskinesia (PCD) consider the presence of a bi-allelic pathogenic variant confirmatory for the diagnosis of PCD, with genetic testing recommended when other confirmatory diagnostic tests are less accessible. We present our experience with genetic testing as first line with a proposed algorithm for high consanguinity populations.

METHODS

Patients with a suspected diagnosis of PCD underwent genetic testing according to a diagnostic algorithm composed of three steps: (1) patients with a previously known causative familial/Bedouin tribal pathogenic variant completed direct testing for a single variant; (2) if the initial test was negative or there was no known pathogenic variant, a PCD genetic panel was completed; (3) if the panel was negative, whole exome sequencing (WES) was completed.

RESULTS

Since the implementation of the protocol, diagnosis was confirmed by genetic testing in 21 patients. The majority of them were of Bedouin origin (81%) and had a positive history of consanguinity (65%). Nine patients (43%) had a sibling with a confirmed diagnosis. Most patients (15/21, 71%) were diagnosed by direct pathogenic variant testing and the remainder by genetic panel (19%) and WES (10%). Disease-causing variants were found in nine genes, with DNAL1 (24%) and DNAAF3, DNAAF5, ZMYND10 (14% each) as the most prevalent ones.

CONCLUSIONS

In highly consanguineous regions, a stepwise genetic testing approach is recommended. This approach may be particularly useful in areas where the ability to obtain confirmatory diagnostic tests through other modalities is less accessible.

Unlocking the Future: Pluripotent Stem Cell-Based Lung Repair

The human respiratory system is susceptible to a variety of diseases, ranging from chronic obstructive pulmonary disease (COPD) and pulmonary fibrosis to acute respiratory distress syndrome (ARDS). Today, lung diseases represent one of the major challenges to the health care sector and represent one of the leading causes of death worldwide. Current treatment options often focus on managing symptoms rather than addressing the underlying cause of the disease. The limitations of conventional therapies highlight the urgent clinical need for innovative solutions capable of repairing damaged lung tissue at a fundamental level. Pluripotent stem cell technologies have now reached clinical maturity and hold immense potential to revolutionize the landscape of lung repair and regenerative medicine. Meanwhile, human embryonic (HESCs) and human-induced pluripotent stem cells (hiPSCs) can be coaxed to differentiate into lung-specific cell types such as bronchial and alveolar epithelial cells, or pulmonary endothelial cells. This holds the promise of regenerating damaged lung tissue and restoring normal respiratory function. While methods for targeted genetic engineering of hPSCs and lung cell differentiation have substantially advanced, the required GMP-grade clinical-scale production technologies as well as the development of suitable preclinical animal models and cell application strategies are less advanced. This review provides an overview of current perspectives on PSC-based therapies for lung repair, explores key advances, and envisions future directions in this dynamic field.

Primary ciliary dyskinesia: An update on contemporary diagnosis

KEY POINTS

Primary ciliary dyskinesia (PCD) is a complex diagnosis without a universal diagnostic test Clinicians must have some skepticism of historic diagnoses of PCD Clinicians should consider a diagnosis of PCD in patients with recalcitrant disease.

Advancing Primary Ciliary Dyskinesia Diagnosis through High-Speed Video Microscopy Analysis

Primary ciliary dyskinesia (PCD) is an inherited disorder that impairs motile cilia, essential for respiratory health, with a reported prevalence of 1 in 16,309 within Hispanic populations. Despite 70% of Puerto Rican patients having the RSPH4A [c.921+3_921+6del (intronic)] founder mutation, the characterization of the ciliary dysfunction remains unidentified due to the unavailability of advanced diagnostic modalities like High-Speed Video Microscopy Analysis (HSVA). Our study implemented HSVA for the first time on the island as a tool to better diagnose and characterize the RSPH4A [c.921+3_921+6del (intronic)] founder mutation in Puerto Rican patients. By applying HSVA, we analyzed the ciliary beat frequency (CBF) and pattern (CBP) in native Puerto Rican patients with PCD. Our results showed decreased CBF and a rotational CBP linked to the RSPH4A founder mutation in Puerto Ricans, presenting a novel diagnostic marker that could be implemented as an axillary test into the PCD diagnosis algorithm in Puerto Rico. The integration of HSVA technology in Puerto Rico substantially enhances the PCD evaluation and diagnosis framework, facilitating prompt detection and early intervention for improved disease management. This initiative, demonstrating the potential of HSVA as an adjunctive test within the PCD diagnostic algorithm, could serve as a blueprint for analogous developments throughout Latin America.

Loss of an extensive ciliary connectome induces proteostasis and cell fate switching in a severe motile ciliopathy

Motile cilia have essential cellular functions in development, reproduction, and homeostasis. Genetic causes for motile ciliopathies have been identified, but the consequences on cellular functions beyond impaired motility remain unknown. Variants in CCDC39 and CCDC40 cause severe disease not explained by loss of motility. Using human cells with pathological variants in these genes, Chlamydomonas genetics, cryo-electron microscopy, single cell RNA transcriptomics, and proteomics, we identified perturbations in multiple cilia-independent pathways. Absence of the axonemal CCDC39/CCDC40 heterodimer results in loss of a connectome of over 90 proteins. The undocked connectome activates cell quality control pathways, switches multiciliated cell fate, impairs microtubule architecture, and creates a defective periciliary barrier. Both cilia-dependent and independent defects are likely responsible for the disease severity. Our findings provide a foundation for reconsidering the broad cellular impact of pathologic variants in ciliopathies and suggest new directions for therapies.

Magnetic Resonance Imaging of Pulmonary and Paranasal Sinus Abnormalities in Children with Primary Ciliary Dyskinesia Compared to Children with Cystic Fibrosis

Rationale: Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are characterized by inherited impaired mucociliary clearance leading to chronic progressive lung disease as well as chronic rhinosinusitis (CRS). The diseases share morphological and functional commonalities on magnetic resonance imaging (MRI) of the lungs and paranasal sinuses, but comparative MRI studies are lacking. Objectives: To determine whether PCD shows different associations of pulmonary and paranasal sinus abnormalities on MRI and lung function test results in children (infants to adolescents) compared with children with CF. Methods: Eighteen children with PCD (median age, 9.5 [IQR, 3.4-12.7] yr; range, 0-18 yr) and 36 age-matched CF transmembrane conductance regulator modulator-naive children with CF (median age, 9.4 [3.4-13.2] yr; range, 0-18 yr) underwent same-session chest and paranasal sinus MRI as well as spirometry (to determine forced expiratory volume in 1 s percent predicted) and multiple-breath washout (to determine lung clearance index z-score). Pulmonary and paranasal sinus abnormalities were assessed using previously validated chest MRI and CRS-MRI scoring systems. Results: Mean chest MRI global score was similar in children with PCD and CF (15.0 [13.5-20.8] vs. 15.0 [9.0-15.0]; P = 0.601). Consolidations were more prevalent and severe in children with PCD (56% vs. 25% and 1.0 [0.0-2.8] vs. 0.0 [0.0-0.3], respectively; P < 0.05). The chest MRI global score correlated moderately with forced expiratory volume in 1 second percent predicted in children with PCD and children with CF (r = -0.523 and -0.687; P < 0.01) and with lung clearance index in children with CF (r = 0.650; P < 0.001) but not in PCD (r = 0.353; P = 0.196). CRS-MRI sum score and mucopyocele subscore were lower in children with PCD than in children with CF (27.5 [26.3-32.0] vs. 37.0 [37.8-40.0] and 2.0 [0.0-2.0] vs. 7.5 [4.8-9.0], respectively; P < 0.01). CRS-MRI sum score did not correlate with chest MRI score in PCD (r = 0.075-0.157; P = 0.557-0.788) but correlated moderately with MRI morphology score in CF (r = 0.437; P < 0.01). Conclusions: MRI detects differences in lung and paranasal sinus abnormalities between children with PCD and those with CF. Lung disease does not correlate with CRS in PCD but correlates in CF.

Dual-color live imaging unveils stepwise organization of multiple basal body arrays by cytoskeletons

For mucociliary clearance of pathogens, tracheal multiciliated epithelial cells (MCCs) organize coordinated beating of cilia, which originate from basal bodies (BBs) with basal feet (BFs) on one side. To clarify the self-organizing mechanism of coordinated intracellular BB-arrays composed of a well-ordered BB-alignment and unidirectional BB-orientation, determined by the direction of BB to BF, we generated double transgenic mice with GFP-centrin2-labeled BBs and mRuby3-Cep128-labeled BFs for long-term, high-resolution, dual-color live-cell imaging in primary-cultured tracheal MCCs. At early timepoints of MCC differentiation, BB-orientation and BB-local alignment antecedently coordinated in an apical microtubule-dependent manner. Later during MCC differentiation, fluctuations in BB-orientation were restricted, and locally aligned BB-arrays were further coordinated to align across the entire cell (BB-global alignment), mainly in an apical intermediate-sized filament-lattice-dependent manner. Thus, the high coordination of the BB-array was established for efficient mucociliary clearance as the primary defense against pathogen infection, identifying apical cytoskeletons as potential therapeutic targets.

Exhaled Breath Analysis Detects the Clearance of Staphylococcus aureus from the Airways of Children with Cystic Fibrosis

BACKGROUND

Electronic nose (eNose) technology can be used to characterize volatile organic compound (VOC) mixes in breath. While previous reports have shown that eNose can detect lung infections with pathogens such as Staphylococcus aureus (SA) in people with cystic fibrosis (CF), the clinical utility of eNose for longitudinally monitoring SA infection status is unknown.

METHODS

In this longitudinal study, a cloud-connected eNose, the SpiroNose, was used for the breath profile analysis of children with CF at two stable visits and compared based on changes in SA infection status between visits. Data analysis involved advanced sensor signal processing, ambient correction, and statistics based on the comparison of breath profiles between baseline and follow-up visits.

RESULTS

Seventy-two children with CF, with a mean (IQR) age of 13.8 (9.8-16.4) years, were studied. In those with SA-positive airway cultures at baseline but SA-negative cultures at follow-up (n = 19), significant signal differences were detected between Baseline and Follow-up at three distinct eNose sensors, i.e., S4 (p = 0.047), S6 (p = 0.014), and S7 (p = 0.014). Sensor signal changes with the clearance of SA from airways were unrelated to antibiotic treatment. No changes in sensor signals were seen in patients with unchanged infection status between visits.

CONCLUSIONS

Our results demonstrate the potential applicability of the eNose as a non-invasive clinical tool to longitudinally monitor pulmonary SA infection status in children with CF.

The genetic framework of primary ciliary dyskinesia assessed by soft computing analysis

BACKGROUND

International guidelines disagree on how best to diagnose primary ciliary dyskinesia (PCD), not least because many tests rely on pattern recognition. We hypothesized that quantitative distribution of ciliary ultrastructural and motion abnormalities would detect most frequent PCD-causing groups of genes by soft computing analysis.

METHODS

Archived data on transmission electron microscopy and high-speed video analysis from 212 PCD patients were re-examined to quantitate distribution of ultrastructural (10 parameters) and functional ciliary features (4 beat pattern and 2 frequency parameters). The correlation between ultrastructural and motion features was evaluated by blinded clustering analysis of the first two principal components, obtained from ultrastructural variables for each patient. Soft computing was applied to ultrastructure to predict ciliary beat frequency (CBF) and motion patterns by a regression model. Another model classified the patients into the five most frequent PCD-causing gene groups, from their ultrastructure, CBF and beat patterns.

RESULTS

The patients were subdivided into six clusters with similar values to homologous ultrastructural phenotype, motion patterns, and CBF, except for clusters 1 and 4, attributable to normal ultrastructure. The regression model confirmed the ability to predict functional ciliary features from ultrastructural parameters. The genetic classification model identified most of the different groups of genes, starting from all quantitative parameters.

CONCLUSIONS

Applying soft computing methodologies to PCD diagnostic tests optimizes their value by moving from pattern recognition to quantification. The approach may also be useful to evaluate atypical PCD, and novel genetic abnormalities of unclear disease-producing potential in the future.

Impact of primary ciliary dyskinesia: Beyond sinobronchial syndrome in Japan

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterized by impaired motile cilia function, particularly in the upper and lower airways. To date, more than 50 causative genes related to the movement, development, and maintenance of cilia have been identified. PCD mostly follows an autosomal recessive inheritance pattern, in which PCD symptoms manifest only in the presence of pathogenic variants in both alleles. Several genes causing PCD have been recently identified that neither lead to situs inversus nor cause definitive abnormalities in ciliary ultrastructure. Importantly, the distribution of disease-causing genes and pathogenic variants varies depending on ethnicity. In Japan, homozygosity for a ∼27.7-kb deletion of DRC1 is estimated to be the most common cause of PCD, presumably as a founder mutation. The clinical picture of PCD is similar to that of sinobronchial syndrome, thus making its differentiation from diffuse panbronchiolitis and other related disorders difficult. Given the diagnostic challenges, many cases remain undiagnosed or misdiagnosed, particularly in adults. While no fundamental cure is currently available, lifelong medical subsidies are provided in Japan, and proper respiratory management, along with continued prevention and treatment of infections, is believed to mitigate the decline in respiratory function. Timely action will be necessary when specific treatments for PCD become available in the future. This narrative review focuses on variations in the disease status of PCD in a non-Western country.

Bronchodilator responsiveness in children with primary ciliary dyskinesia

Background

Reversible airway obstruction is common in children with primary ciliary dyskinesia. However, the diagnostic value of adding bronchodilator (BD) response testing to routine spirometry is unclear.

Methods

This is a retrospective analysis of pulmonary function test results obtained from children with primary ciliary dyskinesia seen as outpatients at the Hospital for Sick Children, Toronto. Spirometry results were collected for every appointment with BD response testing ("Visit", with pre-BD and post-BD measurements) as well as for the previous ("Baseline") and following ("Follow-up") encounters.

Results

A positive BD response was seen in 86 out of 474 (18.1%) of the pulmonary function tests from 82 children with primary ciliary dyskinesia. BD responsiveness was associated with a significant absolute change (±sd) in % predicted forced expiratory volume in 1 s (FEV1) from Baseline to Visit pre-BD (-6.5±10.3%, p<0.001), but not from Baseline to Follow-up (0.4±10.8, p=0.757). Antimicrobial therapy was initiated more commonly following a Visit with a positive BD response (OR 3.8, 95% CI 2.2-6.6) compared to no BD response. Children with a positive BD response had a greater annual decline in FEV1 % predicted compared to those with no BD response (-0.9% per year versus -0.5% per year, p<0.001). The annual decline in FEV1 % predicted was greater in children with multiple compared to one measured positive BD responses (-1.3% per year versus -0.6% per year, p<0.001) and in those not treated with antibiotic therapy following a positive BD response compared to those treated with antibiotics (-1.1% versus -0.6%, p<0.001).

Conclusion

A positive BD response in children with primary ciliary dyskinesia may help identify those at risk for accelerated lung disease progression.

Diagnosis of Primary Ciliary Dyskinesia via Whole Exome Sequencing and Histologic Findings

PURPOSE

To assess the diagnostic potential of whole-exome sequencing (WES) and elucidate the clinical and genetic characteristics of primary ciliary dyskinesia (PCD) in the Korean population.

MATERIALS AND METHODS

Forty-seven patients clinically suspected of having PCD were enrolled at a tertiary medical center. WES was performed in all patients, and seven patients received biopsy of cilia and transmission electron microscopy (TEM).

RESULTS

Overall, PCD was diagnosed in 10 (21.3%) patients: eight by WES (8/47, 17%), four by TEM. Among patients diagnosed as PCD based on TEM results, two patients showed consistent results with WES and TEM of PCD (2/4, 50%). In addition, five patients, who were not included in the final PCD diagnosis group, had variants of unknown significance in PCD-related genes (5/47, 10.6%). The most frequent pathogenic (P)/likely pathogenic (LP) variants were detected in DNAH11 (n=4, 21.1%), DRC1 (n=4, 21.1%), and DNAH5 (n=4, 21.1%). Among the detected 17 P/LP variants in PCD-related genes in this study, 8 (47.1%) were identified as novel variants. Regarding the genotype-phenotype correlation in this study, the authors experienced severe PCD cases caused by the LP/P variants in MCIDAS, DRC1, and CCDC39.

CONCLUSION

Through this study, we were able to confirm the value of WES as one of the diagnostic tools for PCD, which increases with TEM, rather than single gene tests. These results will prove useful to hospitals with limited access to PCD diagnostic testing but with relatively efficient in-house or outsourced access to genetic testing at a pre-symptomatic or early disease stage.

The First Case of a Homozygous CCNO NM 021147.4 Mutation Associated With Primary Ciliary Dyskinesia in Two Indian Siblings

Primary ciliary dyskinesia (PCD) is a heterogeneous autosomal recessive disease marked by organ lateralization in 50% of patients, chronic sinopulmonary disease, infertility in men, and neonatal respiratory distress. Respiratory control cells contain CCNO in their apical cytoplasm, which is necessary for the development of multiciliate cells, basal body amplification, and migration. Reduced generation of multiple motile cilia, a rare form of PCD, has been linked to CCNO gene abnormalities. Individuals with CCNO mutations have been reported to suffer from severe lower respiratory infections that cause progressive impairment of lung function. For the first time, we describe the CCNO NM 021147.4 (c.258 262dup.p, Gln88argfs*8 Homozygous) gene mutation in an Indian consanguineous family that resulted in severe PCD.

Device comparison study to measure nasal nitric oxide in relation to primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a genetic respiratory disease characterized by chronic cough, recurrent respiratory infections, and rhinosinusitis. The measurement of nasal nitric oxide (nNO) against resistance has been suggested as a sensitive screening method. However, current recommendations argue for the use of expensive, chemiluminescence devices to measure nNO. This study aimed to compare nNO measurement using three different devices in distinguishing PCD patients from healthy controls and cystic fibrosis (CF) patients and to evaluate their diagnostic precision. The study included 16 controls, 16 PCD patients, and 12 CF patients matched for age and sex. nNO measurements were performed using a chemiluminescence device (Eco Medics CLD 88sp), and two devices based on electrochemical sensors (Medisoft FeNO+ and NIOX Vero) following standardized guidelines. Correlation estimation, Bland-Altman, ROC curve, and one-way ANOVA were used to assess device differences and diagnostic performance. Significantly lower nNO output values were observed in PCD and CF patients compared to controls during exhalation against resistance. The correlation analysis showed high agreement among the three devices. ROC curve analysis demonstrated 100% sensitivity and specificity at different cut-off values for all devices in distinguishing PCD patients from controls (optimal cut-offs: EcoMedics 73, Medisoft 92 and NIOX 87 (nl min-1)). Higher nNO output values were obtained with the Medisoft and NIOX devices as compared to the EcoMedics device, with a bias of-19 nl min-1(95% CI: -73-35) and -21 nl min-1(-73-31) accordingly. These findings indicate that all three tested devices can potentially serve as diagnostic tools for PCD if device specific cut-off values are used. This last-mentioned aspect warrants further studies and consideration in defining optimal cut-offs for individual device.

Airway microbiota correlated with pulmonary exacerbation in primary ciliary dyskinesia patients

IMPORTANCE

PCD is a rare disease characterized by productive cough, rhinitis, and recurrent infections of the upper and lower airways. Because the diagnosis of PCD is often delayed, patients receive more antibiotics, experience a heavier financial burden, and have a worse prognosis; thus, it is very important to identify the pathogeny and use the correct antibiotic. In this large single-center study of PCD microbiota, we identified an outline of the bacterial microbes from the respiratory tract; furthermore, we found that the microbiota diversity in pediatric sputum was richer than that in pediatric BALF through sequencing, indicating a heterogeneous community structure. The microbiota diversity and richness were lower during pulmonary exacerbation than during pulmonary stabilization. A significantly higher abundance of Pseudomonas had a moderate distinguishing effect for lung exacerbation, which attracted more attention for the study of Pseudomonas therapy in pediatric patients with PCD.

Clinical and genetic analysis of two patients with primary ciliary dyskinesia caused by a novel variant of DNAAF2

BACKGROUND

The study describes the clinical manifestations and variant screening of two Chinese siblings with primary ciliary dyskinesia (PCD). They carry the same DNAAF2 genotype, which is an extremely rare PCD genotype in the Chinese population. In addition, the study illustrated an overview of published variants on DNAAF2 to date.

METHODS

A two-child family was recruited for the study. Clinical manifestations, laboratory tests, bronchoscopic and otoscopic images, and radiographic data were collected. Whole blood was collected from siblings and their parents for whole-exome sequencing (WES) and Sanger sequencing to screen variants.

RESULTS

The two siblings exhibited typical clinical manifestations of PCD. Two compound heterozygous variants in DNAAF2 were detected in both by WES. Nonsense variant c.156 C>A and frameshift variant c.177_178insA, which was a novel variant.

CONCLUSION

The study identified a novel variant of DNAAF2 in Chinese children with a typical phenotype of PCD, which may enrich our knowledge of the clinical, diagnostic and genetic information of DNAAF2-induced PCD in children.

Lack of CFAP54 causes primary ciliary dyskinesia in a mouse model and human patients

Primary ciliary dyskinesia (PCD) is a highly heterogeneous recessive inherited disorder. FAP54, the homolog of CFAP54 in Chlamydomonas reinhardtii, was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella. A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes. Through whole-exome sequencing, compound heterozygous variants c.2649_2657delinC (p. E883Dfs*47) and c.7312_7313insCGCAGGCTGAATTCTTGG (p. T2438delinsTQAEFLA) in a new suspected PCD-relevant gene, CFAP54, were identified in an individual with PCD. Two missense variants, c.4112A>C (p. E1371A) and c.6559C>T (p. P2187S), in CFAP54 were detected in another unrelated patient. In this study, a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression. In addition, a CFAP54 in-frame variant knock-in mouse model was established, which recapitulated the typical symptoms of PCD, including hydrocephalus, infertility, and mucus accumulation in nasal sinuses. Correspondingly, two missense variants were deleterious, with a dramatic reduction in mRNA abundance from bronchial tissue and sperm. The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene. This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.

Investigation and Management of Bronchiectasis in Nontuberculous Mycobacterial Pulmonary Disease

Patients with nontuberculous mycobacterial (NTM) lung infection require life-long attention to their bronchiectasis, whether or not their NTM infection has been cured. The identification of the cause of bronchiectasis and/or coexisting diseases is important because it may affect therapeutic strategies. Airway clearance is the mainstay of bronchiectasis management. It can include multiple breathing techniques, devices, and mucoactive agents. The exact airway clearance regimen should be customized to each individual patient. Chronic pathogenic airway bacteria, such as Pseudomonas aeruginosa, may warrant consideration of eradication therapy and/or chronic use of maintenance inhaled antibiotics.

Ciliary Ultrastructure Assessed by Transmission Electron Microscopy in Adults with Bronchiectasis and Suspected Primary Ciliary Dyskinesia but Inconclusive Genotype

Whole-exome sequencing has expedited the diagnostic work-up of primary ciliary dyskinesia (PCD), when used in addition to clinical phenotype and nasal nitric oxide. However, it reveals variants of uncertain significance (VUS) in established PCD genes or (likely) pathogenic variants in genes of uncertain significance in approximately 30% of tested individuals. We aimed to assess genotype-phenotype correlations in adults with bronchiectasis, clinical suspicion of PCD, and inconclusive whole-exome sequencing results using transmission electron microscopy (TEM) and ciliary image averaging by the PCD Detect software. We recruited 16 patients with VUS in CCDC39, CCDC40, CCDC103, DNAH5, DNAH5/CCDC40, DNAH8/HYDIN, DNAH11, and DNAI1 as well as variants in the PCD candidate genes DNAH1, DNAH7, NEK10, and NME5. We found normal ciliary ultrastructure in eight patients with VUS in CCDC39, DNAH1, DNAH7, DNAH8/HYDIN, DNAH11, and DNAI1. In six patients with VUS in CCDC40, CCDC103, DNAH5, and DNAI1, we identified a corresponding ultrastructural hallmark defect. In one patient with homozygous variant in NME5, we detected a central complex defect supporting clinical relevance. Using TEM as a targeted approach, we established important genotype-phenotype correlations and definite PCD in a considerable proportion of patients. Overall, the PCD Detect software proved feasible in support of TEM.

Clinical Manifestations and Genotype of Primary Ciliary Dyskinesia Diagnosed in Korea: Multicenter Study

PURPOSE

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder that leads to secondary ciliary dysfunction. PCD is a rare disease, and data on it are limited in Korea. This study systematically evaluated the clinical symptoms, diagnostic characteristics, and treatment modalities of pediatric PCD in Korea.

METHODS

This Korean nationwide, multicenter study, conducted between January 2000 and August 2022, reviewed the medical records of pediatric patients diagnosed with PCD. Prospective studies have been added to determine whether additional genetic testing is warranted in some patients.

RESULTS

Overall, 41 patients were diagnosed with PCD in 15 medical institutions. The mean age at diagnosis was 11.8 ± 5.4 years (range: 0.5 months-18.9 years). Most patients (40/41) were born full term, 15 (36.6%) had neonatal respiratory symptoms, and 12 (29.3%) had a history of admission to the neonatal intensive care unit. The most common complaint (58.5%) was chronic nasal symptoms. Thirty-three patients were diagnosed with transmission electron microscopy (TEM) and 12 patients by genetic studies. TEM mostly identified outer dynein arm defects (alone or combined with inner dynein arm defects, n = 17). The genes with the highest mutation rates were DNAH5 (3 cases) and DNAAF1 (3 cases). Rare genotypes (RPGR, HYDIN, NME5) were found as well. Chest computed tomography revealed bronchiectasis in 33 out of 41 patients. Among them, 15 patients had a PrImary CiliAry DyskinesiA Rule score of over 5 points.

CONCLUSIONS

To our knowledge, this is the first multicenter study to report the clinical characteristics, diagnostic methods, and genotypes of PCD in Korea. These results can be used as basic data for further PCD research.

Clinical Characteristics and Immune Responses in Children with Primary Ciliary Dyskinesia during Pneumonia Episodes: A Case-Control Study

OBJECTIVE

This study explored the clinical features and immune responses of children with primary ciliary dyskinesia (PCD) during pneumonia episodes.

METHODS

The 61 children with PCD who were admitted to hospital because of pneumonia were retrospectively enrolled into this study between April 2017 and August 2022. A total of 61 children with pneumonia but without chronic diseases were enrolled as the control group. The clinical characteristics, levels of inflammatory indicators, pathogens, and imaging features of the lungs were compared between the two groups.

RESULTS

The PCD group had higher levels of lymphocytes (42.80% versus 36.00%, p = 0.029) and eosinophils (2.40% versus 1.25%, p = 0.020), but lower neutrophil counts (3.99 versus 5.75 × 109/L, p = 0.011), percentages of neutrophils (46.39% versus 54.24%, p = 0.014), CRP (0.40 versus 4.20 mg/L, p < 0.001) and fibrinogen (257.50 versus 338.00 mg/dL, p = 0.010) levels. Children with PCD and children without chronic diseases were both most commonly infected with Mycoplasma pneumoniae (24.6% versus 51.9%). Children with PCD had significantly more common imaging features, including mucous plugging (p = 0.042), emphysema (p = 0.007), bronchiectasis (p < 0.001), mosaic attenuation (p = 0.012), interstitial inflammation (p = 0.015), and sinusitis (p < 0.001).

CONCLUSION

PCD is linked to immune system impairment, which significantly contributes to our understanding of the pathophysiology of this entity.

Sleep Respiratory Disorders in Children and Adolescents with Cystic Fibrosis and Primary Ciliary Dyskinesia

Cystic fibrosis (CF) and primary ciliary dyskinesia (PCD) are genetic respiratory diseases featured by chronic upper and lower airway inflammation and infection, mainly due to impaired mucociliary clearance due to genetic mutations. Sleep is crucial to healthy children's normal physical and psychological development and has an important value in chronic respiratory diseases. Impaired sleep quality, such as sleep deprivation or insufficient sleep during the night, and sleep respiratory disorders (SRDs) are common in 5% to 30% of the general population. Sleep disruption leads to attention deficits, daytime sleepiness, fatigue and mood disorders and correlates to a worsened quality of life. Furthermore, sleep respiratory disorders (SRSs) are under-recognized comorbidities in CF and PCD patients. SRSs include a spectrum of symptoms ranging from primary snoring through upper airway resistance to obstructive sleep apnea (OSA), nocturnal hypoventilation and hypoxemia occurring in people with moderate to severe lung disease and damaging the disease-related outcomes and quality of life. Effective screening during sleep with polysomnography is very important for the timely initiation of efficacious treatments and to prevent worsened respiratory, metabolic and cardiovascular outcomes. However, the impact of SRDs on health and quality of life is still underinvestigated.

Defective airway intraflagellar transport underlies a combined motile and primary ciliopathy syndrome caused by IFT74 mutations

Ciliopathies are inherited disorders caused by defective cilia. Mutations affecting motile cilia usually cause the chronic muco-obstructive sinopulmonary disease primary ciliary dyskinesia (PCD) and are associated with laterality defects, while a broad spectrum of early developmental as well as degenerative syndromes arise from mutations affecting signalling of primary (non-motile) cilia. Cilia assembly and functioning requires intraflagellar transport (IFT) of cargos assisted by IFT-B and IFT-A adaptor complexes. Within IFT-B, the N-termini of partner proteins IFT74 and IFT81 govern tubulin transport to build the ciliary microtubular cytoskeleton. We detected a homozygous 3-kb intragenic IFT74 deletion removing the exon 2 initiation codon and 40 N-terminal amino acids in two affected siblings. Both had clinical features of PCD with bronchiectasis, but no laterality defects. They also had retinal dysplasia and abnormal bone growth, with a narrowed thorax and short ribs, shortened long bones and digits, and abnormal skull shape. This resembles short-rib thoracic dysplasia, a skeletal ciliopathy previously linked to IFT defects in primary cilia, not motile cilia. Ciliated nasal epithelial cells collected from affected individuals had reduced numbers of shortened motile cilia with disarranged microtubules, some misorientation of the basal feet, and disrupted cilia structural and IFT protein distributions. No full-length IFT74 was expressed, only truncated forms that were consistent with N-terminal deletion and inframe translation from downstream initiation codons. In affinity purification mass spectrometry, exon 2-deleted IFT74 initiated from the nearest inframe downstream methionine 41 still interacts as part of the IFT-B complex, but only with reduced interaction levels and not with all its usual IFT-B partners. We propose that this is a hypomorphic mutation with some residual protein function retained, which gives rise to a primary skeletal ciliopathy combined with defective motile cilia and PCD.

Clinical and Genetic Characterization of Patients with Primary Ciliary Dyskinesia in Southwest Saudi Arabia: A Cross Sectional Study

BACKGROUND

Primary ciliary dyskinesia (PCD, MIM 244400) is an inherited ciliopathy disorder characterized by recurrent sinopulmonary infections, subfertility, and laterality defects. The true incidence of PCD in Saudi Arabia is not known, but it is likely underdiagnosed due to the high prevalence of consanguineous marriages. In this study, we aim to study the clinical and genetic characteristics of PCD patients in the southwestern region of Saudi Arabia to provide guidance to clinicians and researchers studying PCD.

METHODS

This was a cross-sectional study conducted between 2019 and 2023 in Abha Maternity and Children's Hospital. Twenty-eight patients with clinically diagnosed PCD were recruited. The diagnosis of PCD was confirmed via whole-exome sequencing.

RESULTS

A total of 28 patients from 20 families were identified and recruited for this study. The median age of patients was 7.5 years (IQR = 3, 13 years). The people of different sexes were evenly distributed, and 18 patients (64%) had neonatal respiratory distress (NRD). The median age of diagnosis was 5.5 years (IQR = 2, 11 years), while the age when the first symptoms appeared was 3 months old (IQR = 1, 6 months). The prevalence of a chronic wet cough, chronic rhinosinusitis, ear infections were 100% (n = 28), 78.6% (n = 22), and 67.9% (19), respectively. The most common gene in our study was DNAH5, which represented 17.9% (five out of twenty-eight) of the cases. Furthermore, the remaining pathogenic variants included: 14.3% with RSPH9 in four individuals (three families), 14.3% with DNAI2 in four individuals (two families), and 10.7% with LRRC56 in three individuals (one family). The most common findings on the chest CT scans were consolidation (seen in all patients), mucus plugging (seen in 95%), and bronchiectasis (seen in 77%). In the patients with bronchiectasis, the most commonly affected lobes were the right lower lobe (88%) and left lower lobe (76%). The patients with PCD and situs inversus were more likely to experience NRD than the patients with PCD and situs solitus. The median PICADAR score in the patients with PCD and situs inversus (median: 11.5; Q1: 10-Q3: 12.5) was significantly higher compared to those with PCD and situs solitus (median: 7.5; Q1: 5.8-Q3: 8) (U = 10.5; p < 0.001).

CONCLUSION

This study provides preliminary data on the clinical and genetic characteristics of PCD patients in the southwestern region of Saudi Arabia. We found that DNAH5 and RSPH9 genes were the most common genes among the studied population. Furthermore, PCD should be considered for each child with early NRD and laterality defects, and further confirmatory tests are recommended. These findings also highlight the need for greater awareness of the disease in daily clinical practice to facilitate early diagnosis and avoid irreversible lung damage.

Analysis of Clinical Characteristics and Gene Variants Associated with Primary Ciliary Dyskinesia

Background: Primary ciliary dyskinesia (PCD) is considered a monogenic heterogeneous recessive disorder. Objectives: This study aimed to identify clinical characteristics and gene mutations in children with PCD admitted to Quanzhou Women’s and Children’s hospital in China from January 2019 to January 2022. Methods: Clinical manifestations, lung imaging, transmission electron microscopy (TEM) findings, and genetic test results were analyzed in this study. Results: For 8 patients, PCD manifestations included asthma, total visceral inversion, secretory otitis media, adenoid hypertrophy, gastroesophageal reflux, intestinal malrotation with midgut torsion, and bronchiectasis. Primary ciliary dyskinesia-associated gene variants included DNAH11, DNAH5, RSPH4A, and CFAP300. Novel variants of DNAH11 (c.5460 + 5G > C, c.11749_11752delGTTA, and c.5822G > C), DNAH5 (c.4314delT and c.877dupA), RSPH4A (c.1774_1775delTT and c.1949A > G), and CFAP300 (c.603delG) were found in these children. Conclusions: Recurrent cough, expectoration, purulent discharge, bronchiectasis, and visceral inversion provide clues for diagnosing early-onset PCD. Transmission electron microscopy and genetic testing improve early diagnosis, treatment delivery, and prognosis. Novel genotypes identified in this study expand the PCD genotypic spectrum.

Analysis of Clinical Characteristics and Gene Variants Associated with Primary Ciliary Dyskinesia

Background: Primary ciliary dyskinesia (PCD) is considered a monogenic heterogeneous recessive disorder. Objectives: This study aimed to identify clinical characteristics and gene mutations in children with PCD admitted to Quanzhou Women’s and Children’s hospital in China from January 2019 to January 2022. Methods: Clinical manifestations, lung imaging, transmission electron microscopy (TEM) findings, and genetic test results were analyzed in this study. Results: For 8 patients, PCD manifestations included asthma, total visceral inversion, secretory otitis media, adenoid hypertrophy, gastroesophageal reflux, intestinal malrotation with midgut torsion, and bronchiectasis. Primary ciliary dyskinesia-associated gene variants included DNAH11, DNAH5, RSPH4A, and CFAP300. Novel variants of DNAH11 (c.5460 + 5G > C, c.11749_11752delGTTA, and c.5822G > C), DNAH5 (c.4314delT and c.877dupA), RSPH4A (c.1774_1775delTT and c.1949A > G), and CFAP300 (c.603delG) were found in these children. Conclusions: Recurrent cough, expectoration, purulent discharge, bronchiectasis, and visceral inversion provide clues for diagnosing early-onset PCD. Transmission electron microscopy and genetic testing improve early diagnosis, treatment delivery, and prognosis. Novel genotypes identified in this study expand the PCD genotypic spectrum.

Deletions in DNAL1 Cause Primary Ciliary Dyskinesia Across North American Indigenous Populations

We report 4 cases of primary ciliary dyskinesia in unrelated indigenous North American children caused by identical, homozygous, likely pathogenic deletions in the DNAL1 gene. These shared DNAL1 deletions among dispersed indigenous populations suggest that primary ciliary dyskinesia accounts for more lung disease with bronchiectasis than previously recognized in indigenous North Americans.

Treatment response to pulmonary exacerbation in primary ciliary dyskinesia

INTRODUCTION

Pulmonary exacerbation (Pex) are common in pediatric primary ciliary dyskinesia (PCD), however changes in forced expiratory volume in 1 s precent predicted (FEV1pp) during Pex are not well described.

AIM

To assess the evolution of FEV1pp during Pex and to define factors associated with failure to return to baseline lung function.

METHOD

This was a retrospective study of patients with PCD between 2010 and 2022. Pex were defined as the presence of increased respiratory symptoms treated with intravenous (IV) antibiotics. The main outcomes were the changes in FEV1 during therapy and the proportion of patients (responders) achieving ≥90% of baseline FEV1pp values at the end of admission.

RESULTS

The study included 52 Pex events in 28 children with PCD. The rate of responders was 32/41 (78%) at the end of admission. Nonresponse was associated with lower median body mass index (BMI) Z-score (-2.4 vs. -0.4, p < .01) and with a history of IV treated Pex in the previous year (p = .06). For the 22 Pex with available FEV1pp measurements at mid admission, the median relative and absolute improvement from admission to Day 7 was 9.1% and 6.2%, respectively (p- .001), and from Days 7 to 14 was 4.4% and 2.8%, respectively (p = .08).

CONCLUSION

In children with PCD treated with IV antibiotics, the majority of lung function recovery happens during the first week of IV therapy. Lower BMI was associated with nonresponse to therapy.