Primary Ciliary Dyskinesia Research Articles

Pädiatrische Rhinologie.

The following review article highlights key topics in pediatric rhinology that are currently the focus in research and at conferences as well as in the interdisciplinary discussion between otorhinolaryngologists and pediatricians. In particular, congenital malformations such as choanal atresia or nasal dermoid cysts are discussed, followed by statements on the current procedures for sinogenic orbital complications as well as on the diagnosis and therapy of chronic rhinosinusitis in children. Furthermore, updates on the role of the ENT specialist in the care for children with cystic fibrosis and primary ciliary dyskinesia are provided.

Neonatal diagnosis of primary ciliary dyskinesia in a high consanguinity population: a single tertiary center experience.

Though PCD usually presents after birth in term neonates, diagnosing PCD during the neonatal and infancy stages is uncommon, particularly in children who do not exhibit laterality defects. We report our recent experience with the diagnosis of PCD in the neonatal and early infantile period in a highly consanguine population. This was achieved by implementing a novel genetic-based diagnostic approach based on direct testing for recognized regional genetic variants. We conducted a retrospective analysis of children diagnosed with PCD at Soroka University Medical Center during the neonatal or early infantile period between 2020 and 2023. We included children under 3 months of age who had a genetic confirmation of PCD, as evidenced by the presence of two pathogenic variants in recognized genes. Genetic testing targeted regional genetic variants in previously identified PCD genes. Eight patients were included. The median age at diagnosis was 12.5 days. Three (38%) were born prematurely < 34 weeks gestational age. All patients were presented with respiratory distress and hypoxemia after birth. The median duration of oxygen support was 23 days, and upper lobe atelectasis was present in five patients (63%). Congenital cardiac malformation was present in four patients. Organ laterality defects were present in four patients. Genetic mutations identified were in the DNAAF5, DNAL1, DNAAF3, and DNAH1 genes. Conclusion: Neonatal diagnosis of PCD is uncommon, especially in atypical presentations such as children without laterality defects or preterms. Focusing on a genetic diagnosis of the local tribal pathogenic variants promotes a potential cost-efficient test leading to earlier diagnosis. There is a need for a standardized protocol for earlier diagnosis of PCD in high-consanguinity areas. What is Known: • Primary ciliary dyskinesia (PCD) typically presents after birth in term neonates. • Diagnosing PCD during neonatal and infancy stages is challenging, particularly in children without laterality defects. What is New: • A novel genetic-based diagnostic approach was implemented on the neonatal population in a highly consanguine community, focusing on direct testing for regional genetic variants, leading to early and rapid diagnosis of PCD.

A Biallelic Mutation in CCDC103 Impairs Sperm Motility due to the Absence of Dynein Arms

Primary ciliary dyskinesia (PCD) is a rare genetic condition characterized by destructive respiratory disease and laterality abnormalities due to randomized left–right body asymmetry. In men, PCD is also often associated with infertility due to immotile sperm owing to a malfunction of the sperm flagella. Pathogenic mutations have been found in more than 50 genes. Nonetheless, not all patients with PCD experience infertility. Therefore, to better understand the impact of PCD-associated mutations on male fertility, it is necessary to clarify the role of these genes in spermatogenesis. The CCDC103 p.His154Pro mutation has a high prevalence in PCD. Here, we present the identification and functional analysis of a biallelic mutation in CCDC103 identified in a familial case of PCD associated with male infertility. The biallelic CCDC103 mutations, NM_213607:c.161_162del(p.His55Serfs ∗9) and NM_213607:c.461A &gt; C (p.His154Pro), were identified by whole-exome sequencing. Sanger sequencing validation was performed on all available family members, and the mutation was recessively separated with an infertility phenotype. The c.161_162del mutation breaks the reading frame of the protein and, therefore, is predicted to produce a nonfunctional protein. The tertiary structure of CCDC103-mutated protein indicated a significant conformational change that likely affected protein function. Transmission electron microscopy of spermatozoa showed that both the mid and principal regions of the flagellum lacked dynein arms, which was confirmed via immunofluorescence staining. Using the method of laser-assisted immotile sperm selection combined with intracytoplasmic sperm injection, the patient’s wife has a successful clinical pregnancy. These results extend the phenotype spectrum of the CCDC103 mutation in PCD.

Ciliopathy patient variants reveal organelle-specific functions for TUBB4B in axonemal microtubules.

Tubulin, one of the most abundant cytoskeletal building blocks, has numerous isotypes in metazoans encoded by different conserved genes. Whether these distinct isotypes form cell type- and context-specific microtubule structures is poorly understood. Based on a cohort of 12 patients with primary ciliary dyskinesia as well as mouse mutants, we identified and characterized variants in the TUBB4B isotype that specifically perturbed centriole and cilium biogenesis. Distinct TUBB4B variants differentially affected microtubule dynamics and cilia formation in a dominant-negative manner. Structure-function studies revealed that different TUBB4B variants disrupted distinct tubulin interfaces, thereby enabling stratification of patients into three classes of ciliopathic diseases. These findings show that specific tubulin isotypes have distinct and nonredundant subcellular functions and establish a link between tubulinopathies and ciliopathies.

Estimates of primary ciliary dyskinesia prevalence: a scoping review.

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. 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. 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). 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.

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

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

Recessively Inherited Deficiency of Secreted WFDC2 (HE4) Causes Nasal Polyposis and Bronchiectasis.

Rationale: Bronchiectasis is a pathological dilatation of the bronchi in the respiratory airways associated with environmental or genetic causes (e.g., cystic fibrosis, primary ciliary dyskinesia, and primary immunodeficiency disorders), but most cases remain idiopathic. Objectives: To identify novel genetic defects in unsolved cases of bronchiectasis presenting with severe rhinosinusitis, nasal polyposis, and pulmonary Pseudomonas aeruginosa infection. Methods: DNA was analyzed by next-generation or targeted Sanger sequencing. RNA was analyzed by quantitative PCR and single-cell RNA sequencing. Patient-derived cells, cell cultures, and secretions (mucus, saliva, seminal fluid) were analyzed by Western blotting and immunofluorescence microscopy, and mucociliary activity was measured. Blood serum was analyzed by electrochemiluminescence immunoassay. Protein structure and proteomic analyses were used to assess the impact of a disease-causing founder variant. Measurements and Main Results: We identified biallelic pathogenic variants in WAP four-disulfide core domain 2 (WFDC2) in 11 individuals from 10 unrelated families originating from the United States, Europe, Asia, and Africa. Expression of WFDC2 was detected predominantly in secretory cells of control airway epithelium and also in submucosal glands. We demonstrate that WFDC2 is below the limit of detection in blood serum and hardly detectable in samples of saliva, seminal fluid, and airway surface liquid from WFDC2-deficient individuals. Computer simulations and deglycosylation assays indicate that the disease-causing founder variant p.Cys49Arg structurally hampers glycosylation and, thus, secretion of mature WFDC2. Conclusions: WFDC2 dysfunction defines a novel molecular etiology of bronchiectasis characterized by the deficiency of a secreted component of the airways. A commercially available blood test combined with genetic testing allows its diagnosis.

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.

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

We aimed to examine the correlation between clinical characteristics and the pathogenic gene variants in patients with Primary Ciliary Dyskinesia (PCD). 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. We enrolled 74 patients with a median age of 25.58years. 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 4.71years, 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. 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.

Thermal dynamics assessment for multi-phase flow analysis with motile cilia and electric double layer effects: Application of Levenberg–Marquardt backpropagation NNs

Ciliary movement holds substantial importance in the realm of biomedical research. Disorders arising from impaired ciliary motion, such as primary ciliary dyskinesia and specific respiratory ailments, underscore the critical need to investigate both the normal functioning and dysfunction of cilia. Such research is fundamental to the development of effective treatments and therapies. This work explores the application of Levenberg–Marquardt backpropagation neural networks (LMBP-NNs) for simulating the flow of a non-Newtonian Jeffery fluid in peristaltic motion. Inspired by synchronous ciliary movement, microfluidic systems mimicking cilia functionality have been developed. These artificial cilia can generate controlled fluid flow patterns, enabling various applications such as drug delivery, mixing, and particle sorting in lab-on-a-chip devices. The present study focuses on measuring thermal and mass transfer in beating cilia during multiphase peristaltic pumping of Jeffery fluid in two- and three-dimensional channels using transverse magnetohydrodynamics in a porous medium. The governing equations for the non-Newtonian Jeffery fluid in both the fluid and dusty phases are formulated, and exact solutions are calculated for fluid phase velocity, particulate phase velocity, temperature, concentration, and pressure gradient. The physical behavior is investigated by graphing dimensionless parameters for velocity, temperature, and concentration profiles in both solid and liquid phases. The trapping phenomena is depicted by showing streamlines of various dimensionless characteristics such as porosity velocity and volume percentage. The LMBP-NNs approach is then used to train, test, and verify the neural network models using the reference datasets. The accuracy of the LMBP-NN is assessed using statistical data such as mean square error, curve fitting graphs, regression plots, and error histograms. The study also investigates flow model limits for momentum, temperature, and concentration profiles using visual representations. This study illustrates the computational capability of LMBP-NNs in modeling the peristaltic flow of Jeffery fluid and gives useful insights into fluid flow behavior in microfluidic devices containing artificial cilia. The findings help to better understand and optimize these systems for a variety of fluid manipulation and transportation applications.

IJCM_83A: Primary Ciliary Dyskinesia in a child

Background: PCD is rare genetic disorder with incidence of 1:10,000. We present a 10-year-boy who came with recurrent respiratory-infections with Dextrocardia and bilateral Bronchiectasis for interesting clinical presentation. Objective: PCD is rare inherited disease with mutations which impair normal cilia function, characterized by impaired muco-ciliary clearance, causing recurrent-respiratory infections leading to bronchiectasis. Treatment includes preventing and managing complications. Methodology: 10-year-old child came cough-cold since 2 days, and hurried breathing since 1 day. Child had multiple episodes of respiratory- infections which was treated with antibiotics and nebulization on OP basis. Developmental delay also noted, currently in speech domain, can speak 2-3 words. On examination, open mouth breathing and clubbing(grade 3) present. On auscultation bilateral bronchial breath sounds with coarse crepitations. Heart sounds heard louder on right side, but no murmur was heard. Chest X-ray and 2D-ECHO showed Situs-Solitus with Dextrocardia. Child required non-invasive ventilation and IV antibiotics for treatment. Child was weaned off to room air by day 4. CT Thorax done showed bronchiectatic changes in bilateral lung with volume loss of right hemithorax with mediastinal shift to right. CT Nasopharynx and OMC done for open-mouth breathing was normal, and advised steroid nasal spray for nasal blockage. Physiotherapist counselled parents about postural drainage. Genetic testing for PCD was sent, report awaited. He is on regular follow up and doing well. Results: Primary defect in PCD is structure and/or function of cilia leading to accumulation of secretions. Diagnostic criteria includes recurrent chest infections, bronchitis, and rhinitis, with situs-inversus, infertility, decreased mucociliary clearance and cilia showing ultrastructural defect on electron microscopy. We suspected PCD with clinical features and imaging studies. Conclusion: Patients are frequently troubled by repeated infections for which they need to seek medical attention which is reason for morbidity. As there is no specific treatment, early diagnosis and prevention of complication is key to management.

Nontuberculous Mycobacteria, Mucociliary Clearance, and Bronchiectasis.

Nontuberculous mycobacteria (NTM) are environmental and ubiquitous, but only a few species are associated with disease, often presented as nodular/bronchiectatic or cavitary pulmonary forms. Bronchiectasis, airways dilatations characterized by chronic productive cough, is the main presentation of NTM pulmonary disease. The current Cole's vicious circle model for bronchiectasis proposes that it progresses from a damaging insult, such as pneumonia, that affects the respiratory epithelium and compromises mucociliary clearance mechanisms, allowing microorganisms to colonize the airways. An important bronchiectasis risk factor is primary ciliary dyskinesia, but other ciliopathies, such as those associated with connective tissue diseases, also seem to facilitate bronchiectasis, as may occur in Lady Windermere syndrome, caused by M. avium infection. Inhaled NTM may become part of the lung microbiome. If the dose is too large, they may grow excessively as a biofilm and lead to disease. The incidence of NTM pulmonary disease has increased in the last two decades, which may have influenced the parallel increase in bronchiectasis incidence. We propose that ciliary dyskinesia is the main promoter of bronchiectasis, and that the bacteria most frequently involved are NTM. Restoration of ciliary function and impairment of mycobacterial biofilm formation may provide effective therapeutic alternatives to antibiotics.

Primary ciliary dyskinesia caused by mutation of CCNO29 gene in a family report

Primary ciliary dyskinesia caused by mutation of CCNO29 gene in a family report

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.

Comparative characteristics of patients with primary ciliary dyskinesia with or without Kartagener’s syndrome

Primary ciliary dyskinesia (PCD) is a rare hereditary disease, a ciliopathy that is based on a defect in the ultrastructure of the cilia of the epithelium of the respiratory tract and similar structures. All parts of the respiratory tract are affected. About half of the patients with PCD have transposition of the internal organs (Kartagener syndrome – KS).The aim was to investigate the clinical and genetic characteristics of patients with PCD with and without KS.Methods. An assessment of clinical and genetic characteristics was performed in a sample of 127 patients with PCD, who were divided into 2 groups: patients with KS (n = 60) and without KS (n = 67). The groups were compared on the basis of their medical history (according to the PICADAR scale), clinical, instrumental and laboratory data, including the results of light and video microscopy, transmission electron microscopy (TEM) and genetic testing.Results. According to the results of comparative characterization of patients with PCD with and without KS, there were similarities in the medical history, decreased lung function indices, videomicroscopy results – ciliated epithelium beating below 6 Hz, TEM – predominance of dynein arm defect. The PICADAR score was higher in the group with KS than in the group without it; congenital heart defects and renal pathology were found more frequently in patients with KS, while hearing loss and nasal polyposis were found more frequently in patients without KS. Electron microscopy revealed defects in the outer and inner dynein arms of the cilia in 50% of patients in both groups, and a tendency to lack of the central pair of microtubules in 18% of patients without KS. The following genes responsible for PCD were found in both groups: DNAH5, CFAP300 and HYDIN. DNAH5 gene variants were more common for KS patients (61.1%), while HYDIN gene variants were only found in patients with PCD without KS (15.8%).Conclusion. The identified differences may help in the diagnosis of the groups studied.

Multi-institutional Assessment of Otitis Media Epidemiology Using Real-world Data

ObjectivesTo determine rates and risk factors of pediatric otitis media (OM) using real-world electronic health record (PEDSnet) data from January 2009 through May 2021. Study designRetrospective cohort study. SettingSeven pediatric academic health systems that participate in PEDSnet. MethodsChildren <6 months-old at time of first outpatient, Emergency Department, or inpatient visit were included and followed longitudinally. A time-to-event analysis was performed using a Cox proportional hazards model to estimate hazard ratios for OM incidence based on sociodemographic factors and specific health conditions. ResultsThe PEDSnet cohort included 910,265 children, 54.3% male, mean age (months) 1.3 [standard deviation (SD) 1.6] and mean follow up (years) 4.3 (SD 3.2). By age 3 years, 39.6% of children had evidence of one OM episode. OM rates decreased following pneumococcal-13 vaccination (PCV-13) and the COVID-19 pandemic. Along with young age, non-Hispanic Black/African American or Hispanic race/ethnicity, public insurance, higher family income, and male sex had higher incidence rates. Health conditions that increased OM risk included cleft palate [adjusted hazard ratio (aHR) 4.0 [95% confidence interval (CI) 3.9–4.2], primary ciliary dyskinesia [aHR 2.5 (95% CI 1.8–3.5)], trisomy 21 [aHR 2.0 (95% CI 1.9–2.1)], atopic dermatitis [aHR 1.4 (95% CI 1.4–1.4)], and gastroesophageal reflux [aHR1.5 (95% CI 1.5–1.5)]. ConclusionsApproximately 20% of children by age 1 and 40% of children by age 3 years will have experienced an OM episode. OM rates decreased after PCV-13 and COVID-19. Children with abnormal ciliary function or craniofacial conditions, specifically cleft palate, carry the highest risk of OM.

Gene dosage of independent dynein arm motor preassembly factors influences cilia assembly in Chlamydomonas reinhardtii.

Motile cilia assembly utilizes over 800 structural and cytoplasmic proteins. Variants in approximately 58 genes cause primary ciliary dyskinesia (PCD) in humans, including the dynein arm (pre)assembly factor (DNAAF) gene DNAAF4. In humans, outer dynein arms (ODAs) and inner dynein arms (IDAs) fail to assemble motile cilia when DNAAF4 function is disrupted. In Chlamydomonas reinhardtii, a ciliated unicellular alga, the DNAAF4 ortholog is called PF23. The pf23-1 mutant assembles short cilia and lacks IDAs, but partially retains ODAs. The cilia of a new null allele (pf23-4) completely lack ODAs and IDAs and are even shorter than cilia from pf23-1. In addition, PF23 plays a role in the cytoplasmic modification of IC138, a protein of the two-headed IDA (I1/f). As most PCD variants in humans are recessive, we sought to test if heterozygosity at two genes affects ciliary function using a second-site non-complementation (SSNC) screening approach. We asked if phenotypes were observed in diploids with pairwise heterozygous combinations of 21 well-characterized ciliary mutant Chlamydomonas strains. Vegetative cultures of single and double heterozygous diploid cells did not show SSNC for motility phenotypes. When protein synthesis is inhibited, wild-type Chlamydomonas cells utilize the pool of cytoplasmic proteins to assemble half-length cilia. In this sensitized assay, 8 double heterozygous diploids with pf23 and other DNAAF mutations show SSNC; they assemble shorter cilia than wild-type. In contrast, double heterozygosity of the other 203 strains showed no effect on ciliary assembly. Immunoblots of diploids heterozygous for pf23 and wdr92 or oda8 show that PF23 is reduced by half in these strains, and that PF23 dosage affects phenotype severity. Reductions in PF23 and another DNAAF in diploids affect the ability to assemble ODAs and IDAs and impedes ciliary assembly. Thus, dosage of multiple DNAAFs is an important factor in cilia assembly and regeneration.

Primary ciliary dyskinesia (Kartagener syndrome): a case of late diagnosis and follow-up

Primary ciliary dyskinesia (PCD) is an autosomal recessive disease that develops as a result of an ultrastructural defect of the cilia and flagella. The symptoms are non-specific, especially in childhood, and are characterized by recurrent rhinitis and bronchitis, often with obstruction. Half of the patients with PCD are diagnosed with such clear clinical manifestation as Kartagener’s syndrome (chronic bronchitis, chronic sinusitis, reverse position of internal organs (situs inversus), but even in these cases the diagnosis can be difficult.The aim of this paper was to demonstrate a clinical case of late diagnosis of PCD in a child with classic Kartagener syndrome and concomitant atopy, and the results of 11 years of follow-up and microbiological monitoring. The stages of the diagnostic search are presented in detail and typical errors on the way to diagnosis are analyzed.Conclusion. This clinical observation demonstrates the difficulties of diagnosing PCD in a patient with concomitant atopy. It is noted that appropriate continued monitoring and timely therapy are crucial for children with PCD. The need to standardize approaches to the diagnosis and management of patients with PCD, including continuity during transfer to the adult healthcare network, is emphasized.

The primary ciliary dyskinesia-related genetic risk score is associated with susceptibility to adult-onset asthma.

Disturbance of mucociliary clearance is an important factor in the pathogenesis of asthma. We hypothesized that common variants in genes responsible for ciliary function may contribute to the development of asthma with certain phenotypes. Three independent adult Japanese populations (including a total of 1,158 patients with asthma and 2,203 non-asthmatic healthy participants) were studied. First, based on the ClinVar database (https://www.ncbi.nlm.nih.gov/clinvar/), we selected 12 common single-nucleotide polymorphisms (SNPs) with molecular consequences (missense, nonsense, and 3'-untranslated region mutation) in 5 primary ciliary dyskinesia (PCD)-related genes and calculated a PCD-genetic risk score (GRS) as a cumulative effect of these PCD-related genes. Second, we performed a two-step cluster analysis using 3 variables, including PCD-GRS, forced expiratory volume in 1 second (%predicted FEV1), and age of asthma onset. Compared to adult asthma clusters with an average PCD-GRS, clusters with high and low PCD-GRS had similar overall characteristics: adult-onset, female predominance, preserved lung function, and fewer features of type 2 immunity as determined by IgE reactivity and blood eosinophil counts. The allele frequency of rs1530496, a SNP representing an expression quantitative trait locus (eQTL) of DNAH5 in the lung, showed the largest statistically significant difference between the PCD-GRS-High and PCD-GRS-Low asthma clusters (p = 1.4 x 10-15). Genes associated with PCD, particularly the common SNPs associated with abnormal expression of DNAH5, may have a certain influence on the development of adult-onset asthma, perhaps through impaired mucociliary clearance.

A new software for automated analysis of respiratory tract ciliary epithelium movement for the diagnosis of primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a rare hereditary disease. In this ciliopathy, the disturbed structure and motility of the ciliary epithelium negatively affects the ciliary function and leads to prominent decrease or absence of mucociliary clearance. The European guidelines recommend analyzing the cilia beat frequency (СBF) in a native preparation or in ALI culture using light microscopy as one of the methods to confirm the diagnosis of PCD.The aim of this project was to create software for automated analysis of the movement/beating of the ciliary epithelium of the respiratory tract for the diagnosis of primary ciliary dyskinesia using digital high-speed video microscopy in vivo and in vitro.Methods. Five healthy donors and 10 patients with suspected PCD underwent nasal epithelial brush biopsy. The preparations were examined with a transmission electron microscope in vivo. Epithelial cells were also isolated from the nasal biopsy specimen, and ciliogenesis of these cells was performed by ALI-culturing, followed by digital high-speed video microscopy and assessment of the number of active cells and cilia beating frequency. The resulting video images were used to create the software.Results. Software for determination of ciliary epithelium beat frequency in primary ciliary dyskinesia (PCD HighSpeed Video Microscopy Analysis – PCD HSVMA) was created to optimize the diagnosis of PCD by light microscopy (software registration number 2023687245). The software is designed to count the number of active cells of ciliary epithelium and CBF (Hz) by digital high-speed video microscopy in vivo and in vitro in ALI-culture. PCD HSVMA software features storage of patient data, display of heat map, formation of a large server database of patients and video files, building of color and static histograms, processing of several areas in one video. Our software has a number of advantages over CiliarMove and Cilialyzer and has high correlation of CFB (Hz) estimation with these products.Conclusion. Our software can be used for improvement of PCD diagnostics in laboratories of healthcare institutions, in scientific institutions and can be included in specialist educational programs for laboratory doctors, pediatricians, general practitioners, pulmonologists, diagnosticians (endoscopists).