Primary Ciliary Dyskinesia: An Update on Clinical Aspects, Genetics, Diagnosis, and Future Treatment Strategies

Impact of local anesthesia on ciliary dyskinesia diagnosis by digital high-speed videomicroscopy

This prospective study investigates the impact of local anesthesia on ciliary function in nasal epithelium. The primary objective was to assess whether lidocaine 2% and naphazoline 0.5% nasal spray alter ciliary beat frequency and pattern in subjects undergoing nasal brushing, aiming to enhance primary ciliary dyskinesia (PCD) diagnosis.

HYPOTHESIS

It was hypothesized that local anesthesia administration would not significantly affect ciliary function in nasal epithelium.

STUDY DESIGN

A prospective, simple-blind randomized study was conducted between 2020 and 2023. The study employed digital high-speed videomicroscopy to analyze ciliary beat frequency and pattern.

PATIENT/SUBJECT SELECTION

A cohort of 38 participants was recruited, consisting of 25 healthy volunteers and 13 referred individuals (including seven diagnosed with PCD). Selection criteria ensured the absence of chronic respiratory diseases, recent respiratory tract infections, or regular use of nasal medications.

METHODOLOGY

Participants underwent nasal brushing with administration of lidocaine and naphazoline nasal spray in one nostril and saline in the contralateral nostril. Ciliary beat frequency and pattern were measured using digital high-speed video microscopy.

RESULTS

Nasal spray administration did not significantly alter ciliary beat frequency or pattern compared to saline (p = 0.841 and p = 0.125, respectively). Subgroup analysis revealed consistent results across healthy volunteers, referred patients, and PCD patients.

CONCLUSION

Local anesthesia with lidocaine and naphazoline spray did not affect ciliary function outcomes. These findings support the safe use of these agents in clinical practice for PCD diagnostic procedures. Further research with larger cohorts is warranted for validation.

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

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

A novel homozygous missense TTC12 variant identified in an infertile Pakistani man with severe oligoasthenoteratozoospermia and primary ciliary dyskinesia

TTC12 is a cytoplasmic and centromere-localized protein that plays a role in the proper assembly of dynein arm complexes in motile cilia in both respiratory cells and sperm flagella. This finding underscores its significance in cellular motility and function. However, the wide role of TTC12 in human spermatogenesis-associated primary ciliary dyskinesia (PCD) still needs to be elucidated. Whole-exome sequencing (WES) and Sanger sequencing were performed to identify potentially pathogenic variants causing PCD and multiple morphological abnormalities of sperm flagella (MMAF) in an infertile Pakistani man. Diagnostic imaging techniques were used for PCD screening in the patient. Real-time polymerase chain reaction (RT‒PCR) was performed to detect the effect of mutations on the mRNA abundance of the affected genes. Papanicolaou staining and scanning electron microscopy (SEM) were carried out to examine sperm morphology. Transmission electron microscopy (TEM) was performed to examine the ultrastructure of the sperm flagella, and the results were confirmed by immunofluorescence staining. Using WES and Sanger sequencing, a novel homozygous missense variant (c.C1069T; p.Arg357Trp) in TTC12 was identified in a patient from a consanguineous family. A computed tomography scan of the paranasal sinuses confirmed the symptoms of the PCD. RT-PCR showed a decrease in TTC12 mRNA in the patient's sperm sample. Papanicolaou staining, SEM, and TEM analysis revealed a significant change in shape and a disorganized axonemal structure in the sperm flagella of the patient. Immunostaining assays revealed that TTC12 is distributed throughout the flagella and is predominantly concentrated in the midpiece in normal spermatozoa. In contrast, spermatozoa from patient deficient in TTC12 showed minimal staining intensity for TTC12 or DNAH17 (outer dynein arms components). This could lead to MMAF and result in male infertility. This novel TTC12 variant not only illuminates the underlying genetic causes of male infertility but also paves the way for potential treatments targeting these genetic factors. This study represents a significant advancement in understanding the genetic basis of PCD-related infertility.

Evaluation of screening tools for primary ciliary dyskinesia in Egypt: single center study

BACKGROUND

Primary ciliary dyskinesia (PCD) is a chronic respiratory illness that places significant strain on the healthcare system due to the complexity and expense of its diagnosis and treatment methods. The diagnostic process typically requires skilled technicians and an assortment of intricate, costly, and time-consuming approaches. Implementing screening tools can enhance efficiency by focusing the diagnostic process on those strongly suspected of having PCD. Tools such as the PCD Rule (PICADAR), North America Criteria Defined Clinical Features (NA-CDCF), the Clinical Index Score (CI), and the newly proposed CInew13 could potentially serve as useful screening tools. This study aims to examine the effectiveness of these tools individually, compare their performance against each other, and assess their results relative to prior research.

METHODS

We conducted a diagnostic accuracy test on 83 Egyptian patients referred to Alexandria University Children's Hospital for potential PCD diagnosis between January 2015 and December 2022. The scores obtained from the screening tools were calculated and assessed.

RESULTS

Of the initial group, 10 patients were ruled out because they fit other diagnostic parameters. Forty-three cases received a confirmed diagnosis, while 30 did not. Notably, the confirmed cases consistently scored higher on our screening tools than those that remained unconfirmed (p <.001, for all tested scores). We used receiver operating characteristic curves to assess and compare the effectiveness of each tool. The NA-CDCF had the smallest area under curve 0.736 (95% confiedence interval 0.619-0.832); in contrast, the CI score had the largest 0.898 (95% confidence interval 0.808-0.957).

CONCLUSION

All the tools tested were effective in identifying suitable patients for PCD testing at statistically significant levels. However, the PICADAR and NA-CDCF scores' performance did not significantly differ in the current study. The CI and CInew13 scores, on the other hand, outperformed both.

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.

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.

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.

Nasal Disorders

Nasal obstruction, rhinorrhea, and epistaxis are common presenting concerns in primary care clinics. Nasal disorders affect the quality of life for many children and families. Rarely, these complaints may represent a life-threatening condition among infant obligate nasal breathers or cases of unusual pathology. The most common causes of rhinorrhea and nasal obstruction vary by age and include physiologic, infectious, allergic, foreign body, irritant, and traumatic causes. Less commonly, children may have congenital malformations, sinonasal masses, or autoimmune disease. The most common causes of epistaxis are inflammatory, environmental, and traumatic causes and medication misuse, but rarely, children may have predisposing anatomic, hematologic, or vascular abnormalities or even sinonasal tumors. In this article, we provide a thorough review of the common nasal disorders treated every day in primary care clinics and mention briefly some of the rare but serious cases that may be overlooked without considering a full differential diagnosis.

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.

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.

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.

Genome-wide association study meta-analysis supports association between MUC1 and ectopic pregnancy

STUDY QUESTION

Can we identify genetic variants associated with ectopic pregnancy by undertaking the first genome-wide association study (GWAS) leveraging two large-scale biobank initiatives?

SUMMARY ANSWER

We identified two novel genome-wide significant associations with ectopic pregnancy, highlighting MUC1 (mucin 1) as the most plausible affected gene.

WHAT IS KNOWN ALREADY

Ectopic pregnancy is an important cause of maternal morbidity and mortality worldwide. Despite being a common early pregnancy complication, the genetic predisposition to this condition remains understudied and no large scale genetic studies have been performed so far.

STUDY DESIGN, SIZE, DURATION

A GWAS meta-analysis including 7070 women with ectopic pregnancy and 248 810 controls from Estonian Biobank and the FinnGen study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We identified ectopic pregnancy cases from national registers by ICD (International Classification of Disease) codes (ICD-10 O00), and all remaining women were considered controls. We carried out standard GWAS meta-analysis and additionally annotated GWAS signals, analysed co-localization with quantitative trait loci, estimated genetic correlations and identified associated phenotypes to characterize the genetic signals, as well as to analyse the genetic and phenotypic relationships with the condition.

MAIN RESULTS AND THE ROLE OF CHANCE

We identified two genome-wide significant loci on chromosomes 1 (rs4971091, P = 5.32×10-9) and 10 (rs11598956, P = 2.41×10-8) potentially associated with ectopic pregnancy. Follow-up analyses propose MUC1, which codes for an epithelial glycoprotein with an important role in barrier function, as the most likely candidate gene for the association on chromosome 1. We also characterize the phenotypic and genetic correlations with other phenotypes, identifying a genetic correlation with smoking and diseases of the (genito)urinary and gastrointestinal system, and phenotypic correlations with various reproductive health diagnoses, reflecting the previously known epidemiological associations.

LARGE SCALE DATA

The GWAS meta-analysis summary statistics are available from the GWAS Catalogue (GCST90272883).

LIMITATIONS, REASONS FOR CAUTION

The main limitation is that the findings are based on European-based ancestry populations, with limited data on other populations, and we only captured maternal genomes. Additionally, further larger meta-analysis or independent studies are needed to validate these findings.

WIDER IMPLICATIONS OF THE FINDINGS

This study encourages the use of large-scale genetic datasets to unravel genetic factors linked to ectopic pregnancy, which is difficult to study in experimental settings. Increased sample size might bring additional genetic factors associating with ectopic pregnancy and inform its heritability. Altogether, our results provide more insight into the biology of ectopic pregnancy and, accordingly, the biological processes governing embryo implantation.

STUDY FUNDING/COMPETING INTEREST(S)

N.P.G. was supported by MATER Marie Sklodowska-Curie which received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No. 813707. This study was funded by European Union through the European Regional Development Fund Project No. 2014-2020.4.01.15-0012 GENTRANSMED. Computations were performed in the High-Performance Computing Center of University of Tartu. The authors declare no competing interests.

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.

Identification of a novel splice site mutation in the DNAAF4 gene of a Chinese patient with primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a rare hereditary orphan condition that results in variable phenotypes, including infertility. About 50 gene variants are reported in the scientific literature to cause PCD, and among them, dynein axonemal assembly factor 4 ( DNAAF4 ) has been recently reported. DNAAF4 has been implicated in the preassembly of a multiunit dynein protein essential for the normal function of locomotory cilia as well as flagella. In the current study, a single patient belonging to a Chinese family was recruited, having been diagnosed with PCD and asthenoteratozoospermia. The affected individual was a 32-year-old male from a nonconsanguineous family. He also had abnormal spine structure and spinal cord bends at angles diagnosed with scoliosis. Medical reports, laboratory results, and imaging data were investigated. Whole-exome sequencing, Sanger sequencing, immunofluorescence analysis, hematoxylin-eosin staining, and in silico functional analysis, including protein modeling and docking studies, were used. The results identified DNAAF4 disease-related variants and confirmed their pathogenicity. Genetic analysis through whole-exome sequencing identified two pathogenic biallelic variants in the affected individual. The identified variants were a hemizygous splice site c.784-1G>A and heterozygous 20.1 Kb deletion at the DNAAF4 locus, resulting in a truncated and functionless DNAAF4 protein. Immunofluorescence analysis indicated that the inner dynein arm was not present in the sperm flagellum, and sperm morphological analysis revealed small sperm with twisted and curved flagella or lacking flagella. The current study found novel biallelic variants causing PCD and asthenoteratozoospermia, extending the range of DNAAF4 pathogenic variants in PCD and associated with the etiology of asthenoteratozoospermia. These findings will improve our understanding of the etiology of 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.

Molecular defects in primary ciliary dyskinesia are associated with agenesis of the frontal and sphenoid paranasal sinuses and chronic rhinosinusitis

Background: Primary ciliary dyskinesia (PCD; MIM 242650) is a rare genetic disorder characterized by malfunction of the motile cilia resulting in reduced mucociliary clearance of the airways. Together with recurring infections of the lower respiratory tract, chronic rhinosinusitis (CRS) is a hallmark symptom of PCD. Data on genotype-phenotype correlations in the upper airways are scarce. Materials and methods: We investigated the prevalence, radiologic severity, and impact on health-related quality of life (HrQoL) of CRS in 58 individuals with genetically confirmed PCD. Subgroup analysis was performed according to the predicted ultrastructural phenotype based on genetic findings. Results: Among 58 individuals harboring pathogenic variants in 22 distinct genes associated with PCD, all were diagnosed with CRS, and 47% underwent sinus surgery. A total of 36 individuals answered a German-adapted version of the 20-item Sinonasal Outcome Test (SNOT-20-GAV) with a mean score of 35.8 ± 17, indicating a remarkably reduced HrQoL. Paranasal sinus imaging of 36 individuals showed moderate-to-severe opacification with an elevated Lund-Mackay Score (LMS) of 10.2 ± 4.4. Bilateral agenesis of frontal sinus (19%) and sphenoid sinus (9.5%) was a frequent finding in individuals aged 16 years or older. Subgroup analysis for predicted ultrastructural phenotypes did not identify differences in HrQoL, extent of sinus opacification, or frequency of aplastic paranasal sinuses. Conclusion: PCD is strongly associated with CRS. The high burden of disease is indicated by decreased HrQoL. Therefore, the upper airways of PCD individuals should be evaluated and managed by ear-nose-throat (ENT) specialists. Genetically determined PCD groups with predicted abnormal versus (near) normal ultrastructure did not differ in disease severity. Further studies are needed to gain evidence-based knowledge of the phenotype and management of upper airway manifestations in PCD. In addition, individuals with agenesis of the frontal and sphenoid paranasal sinuses and chronic respiratory symptoms should be considered for a diagnostic evaluation of PCD.

Inherently disordered regions of axonemal dynein assembly factors

The dynein-driven beating of cilia is required to move individual cells and to generate fluid flow across surfaces and within cavities. These motor enzymes are highly complex and can contain upwards of 20 different protein components with a total mass approaching 2 MDa. The dynein heavy chains are enormous proteins consisting of ~4500 residues and ribosomes take approximately 15 min to synthesize one. Studies in a broad array of organisms ranging from the green alga Chlamydomonas to humans has identified 19 cytosolic factors (DNAAFs) that are needed to specifically build axonemal dyneins; defects in many of these proteins lead to primary ciliary dyskinesia in mammals which can result in infertility, severe bronchial problems, and situs inversus. How all these factors cooperate in a spatially and temporally regulated manner to promote dynein assembly in cytoplasm remains very uncertain. These DNAAFs contain a variety of well-folded domains many of which provide protein interaction surfaces. However, many also exhibit large regions that are predicted to be inherently disordered. Here I discuss the nature of these unstructured segments, their predicted propensity for driving protein phase separation, and their potential for adopting more defined conformations during the dynein assembly process.

Short-interval second ejaculation improves sperm quality, blastocyst formation in oligoasthenozoospermic males in ICSI cycles: a time-lapse sibling oocytes study

Background

Does short-interval second ejaculation improve sperm quality, embryo development and clinical outcomes for oligoasthenozoospermia males received intracytoplasmic sperm injection (ICSI) treatment?

Methods

All enrolled male patients underwent short-interval secondary ejaculation on the day of oocyte retrieval, and 786 sibling MII oocytes from 67 cycles were equally divided into two groups based on whether the injected spermatozoons originated from the first or second ejaculation. Semen parameters, embryo development efficiency, morphokinetic parameters and clinical outcomes were compared between the two groups to assess the efficiency and clinical value of short-interval second ejaculation in ICSI cycles.

Results

Short-interval second ejaculation significantly improved sperm motility, normal morphological rate, and sperm DNA integrity both before and after sperm swim-up. The high-quality blastocyst rate (24.79% versus 14.67%), available blastocyst rate (57.56% versus 48.44%), and oocyte utilization rate (52.93% versus 45.29%) were significantly higher in the second ejaculation group (P<0.05). The clinical pregnancy rate (59.09% versus 47.37%), implantation rate (42.11% versus 32.35%) and live birth rate (40.91% versus 31.58%) were higher in the second ejaculation group, but the differences were not significant (P>0.05). Time-lapse analysis showed that morphokinetic time points after the 7-cell stage were earlier in the second ejaculation group but without a significant difference (P>0.05), and abnormal embryo cleavage patterns between the two groups were not significantly different (P>0.05).

Conclusions

Short-interval second ejaculation significantly improves sperm quality in oligoasthenozoospermic males, and is beneficial for blastocyst formation efficiency in ICSI cycles. This study suggested a non-invasive and simple but effective strategy for improving ICSI treatment outcomes.

Restoring Ciliary Function: Gene Therapeutics for Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a genetic disease characterized by defects in motile cilia, which play an important role in several organ systems. Lung disease is a hallmark of PCD, given the essential role of cilia in airway surface defense. Diagnosis of PCD is complicated due to its reliance on complex tests that are not utilized by every clinic and also its phenotypic overlap with several other respiratory diseases. Nonetheless, PCD is increasingly being recognized as more common than once thought. The disease is genetically complex, with several genes reported to be associated with PCD. There is no cure for PCD, but gene therapy remains a promising therapeutic strategy. In this review, we provide an overview of the clinical symptoms, diagnosis, genetics, and current treatment regimens for PCD. We also describe PCD model systems and discuss the therapeutic potential of different gene therapeutics for targeting the intended cellular target, the ciliated cells of the airway.

Primary ciliary dyskinesia

BACKGROUND AND OBJECTIVES

Primary ciliary dyskinesia (PCD, ORPHA:244) is a group of rare genetic disorders characterized by dysfunction of motile cilia. It is phenotypically and genetically heterogeneous, with more than 50 genes involved. Thanks to genetic, clinical, and functional characterization, immense progress has been made in the understanding and diagnosis of PCD. Nevertheless, it is underdiagnosed due to the heterogeneous phenotype and complexity of diagnosis. This review aims to help clinicians navigate this heterogeneous group of diseases. Here, we describe the broad spectrum of phenotypes associated with PCD and address pitfalls and difficult-to-interpret findings to avoid misinterpretation.

METHOD

Review of literature CONCLUSION: PCD diagnosis is complex and requires integration of history, clinical picture, imaging, functional and structural analysis of motile cilia and, if available, genetic analysis to make a definitive diagnosis. It is critical that we continue to expand our knowledge of this group of rare disorders to improve the identification of PCD patients and to develop evidence-based therapeutic approaches.

Novel Pathogenic DNAH5 Variants in Primary Ciliary Dyskinesia: Association with Visceral Heterotaxia and Neonatal Cholestasis

The dynein axonemal heavy chain 5 gene codes for a subunit of axonemal dynein necessary for ciliary motor function. Though research has elucidated the consequences of some variants in this gene, it is still unclear whether many variants in the DNAH5 locus are benign or pathogenic due to the rarity of primary ciliary dyskinesia (PCD, of which Kartagener's syndrome is a subset). Here, we introduce the case of an infant boy presenting with the classical findings of PCD along with visceral heterotaxia and neonatal cholestasis. Genetic testing indicated that the patient is a compound heterozygote with a pathogenic c.8498G > A (known as pathogenic) on the maternally derived allele and two variants of uncertain significance, c.1206T > A and c.7800T > G, on the paternally derived allele. As PCD is autosomal recessive, we conclude that one, or both, of these paternally derived variants are pathogenic. To our knowledge, this is the first time that the clinical implications of c.1206T > A (p.Asn402Lys) and c.7800T > G (p.Ile2600Met) are documented. Furthermore, we use this case as an example to recommend clinicians to assess for PCD and laterality defects when presented with severe infantile cholestasis. While the association of cholestasis with PCD is relatively uncommon, PCD is a risk factor for increased prevalence of biliary atresia and infections, both of which are known causes of cholestasis in early infancy.

Bronchiectasis Assessment in Primary Ciliary Dyskinesia: A Non-Invasive Approach Using Forced Oscillation Technique

Primary ciliary dyskinesia (PCD) is an autosomal recessive disorder that results from the dysfunction of motile cilia, which can cause chronic upper and lower respiratory infections leading to bronchiectasis. However, there is a need for additional tools to monitor the progression of bronchiectasis in PCD. The forced oscillation technique (FOT) is an effort-independent lung function test that can be used to evaluate respiratory mechanics. In this retrospective study, we aimed to describe the radiographic findings associated with respiratory impedance (resistance (Rrs) and reactance (Xrs)) measured by FOT in six adult PCD patients and one pediatric with the (RSPH4A (c.921+3_921+6delAAGT (intronic)) founder mutation. We compared the radiographic findings on a high-resolution chest computed tomography (CT) scan with the FOT results. Our findings suggest that respiratory impedance measured by FOT may be a valuable tool for detecting and monitoring the progression of bronchiectasis in PCD patients with the (RSPH4A (c.921+3_921+6delAAGT (intronic)) founder mutation. However, further research is necessary to validate these results and determine the sensitivity and specificity of bronchiectasis monitoring in PCD patients with other genetic mutations.

Basic, translational and clinical aspects of bronchiectasis in adults

Bronchiectasis is a common progressive respiratory disease with recognisable radiological abnormalities and a clinical syndrome of cough, sputum production and recurrent respiratory infections. Inflammatory cell infiltration into the lung, in particular neutrophils, is central to the pathophysiology of bronchiectasis. Herein we explore the roles and relationships between infection, inflammation and mucociliary clearance dysfunction in the establishment and progression of bronchiectasis. Microbial and host-mediated damage are important processes underpinning bronchiectasis and the relative contribution of proteases, cytokines and inflammatory mediators to the propagation of inflammation is presented. We also discuss the emerging concept of inflammatory endotypes, defined by the presence of neutrophilic and eosinophilic inflammation, and explore the role of inflammation as a treatable trait. Current treatment for bronchiectasis focuses on treatment of underlying causes, enhancing mucociliary clearance, controlling infection and preventing and treating complications. Data on airway clearance approaches via exercise and mucoactive drugs, pharmacotherapy with macrolides to decrease exacerbations and the usefulness of inhaled antibiotics and bronchodilators are discussed, finishing with a look to the future where new therapies targeting host-mediated immune dysfunction hold promise.

Primary ciliary dyskinesia: A multicenter survey on clinical practice and patient management in Italy

INTRODUCTION

There are no recent data on primary ciliary dyskinesia (PCD) distribution, diagnosis and treatment in Italy.

METHODS

A descriptive study based on a survey questionnaire. It consisted of three sections (patients, diagnosis, and treatment), and sent to all the Italian PCD Centers.

RESULTS

Questionnaires obtained from 20/22 centers in 12/20 regions showed that the total number of PCD patients treated at the participating centers was of 416. Out of all centers, 55% follow <20 patients, two centers have >40 patients, and 75% follow both pediatric and adults. Age at diagnosis was between 4 and 8 years in 45% of the centers, <3 years in three centers. Nasal nitric oxide, transmission electron microscopy and ciliary high-speed video microscopy are performed in 75%, 90%, and 40% of centers, respectively. Immunofluorescence is available in five centers. Genetic analysis is offered in 55% of the centers, and in seven centers >50% of the patients have a known genetic profile. Patients treated at all centers receive inhaled saline solutions, corticosteroids and chest physiotherapy. Prophylactic antibiotics and mucolytics are prescribed in 95% and 50% of the centers, respectively. Pseudomonas infection is treated with oral or inhaled antibiotics.

CONCLUSIONS

Many Italian centers care for a small number of pediatric and adult patients, and diagnosis is often delayed. We found a great variability in the available diagnostic procedures, as well in the prescribed therapies. Our study will help to uniform diagnostic algorithm and share treatments protocols for PCD in Italy and allowed to set specific national goals.

Cystic Fibrosis Screen Positive, Inconclusive Diagnosis Genotypes in People with Cystic Fibrosis from the U.S. Patient Registry

Rationale: Variants within the cystic fibrosis (CF) transmembrane conductance regulator gene, CFTR, that are of unknown significance or are categorized as non-CF causing may be observed in persons with CF. These variants are frequently detected in children with inconclusive newborn screen results and, in some cases, may be associated with a benign presentation in early childhood that progresses to a CF phenotype later in life. Objectives: To analyze data from individuals enrolled in the U.S. Cystic Fibrosis Foundation Patient Registry who have received a diagnosis of CF and who have variants found in a population of children with a CF screen positive, inconclusive diagnosis (CFSPID). Methods: This retrospective review analyzed registry data from individuals with a diagnosis of CF who also harbor one or more variants of interest because of their frequency within a CFSPID population and/or their interpretation as non-CF causing. Three groups were defined by the number of CF-causing variants identified (CF-Cx2, CF-Cx1, and CF-Cx0), which were reported in addition to the variant(s) of interest. Multivariate quantile regression modeling of the outcome for forced expiratory volume in 1 second (FEV1) generated a disease severity score for each person determined by six selected variables. Median scores were calculated for the three groups. Results: Patients carrying one CF-causing variant and at least one variant of interest (CF-Cx1) had higher median disease severity scores compared with those carrying CF-Cx2, suggesting a milder phenotype (P < 0.05). However, there was no statistically significant difference in scores between CF-Cx2 and the two other groups combined (CF-Cx1 and CF-Cx0; P = 0.33). Analysis revealed that the CF-Cx1 and CF-Cx0 groups, when compared with the CF-Cx2 group, had later median diagnoses (8 years vs. newborn; P < 0.0001), lower median sweat chloride (48 mmol/L vs. 94.5 mmol/L; P < 0.0001), lower prevalence of pancreatic insufficiency (29% vs. 78%; P < 0.0001), and higher median FEV1% predicted (95% vs. 87%; P = 0.0002). Conclusions: Individuals with CF who have specific variants frequently identified in children with CFSPID have a similar range of disease severity scores compared with those who have two CF-causing variants, but a milder phenotype overall. Variants that should be given careful scrutiny because of their high prevalence are G576A+R668C, T854T, R75Q, F1052V, R1070W, R31C, and L967S.

Impact of Bepanthen® and dexpanthenol on human nasal ciliary beat frequency in vitro

BACKGROUND

Dexpanthenol-containing ointments/fluids are recommended to restore impaired nasal mucosa. To date, there are no data about the influence of dexpanthenol or formulations including dexpanthenol on ciliary beat frequency (CBF) of nasal epithelial cells.

METHODS

We tested the ciliary beat frequency of human nasal epithelial cells in RPMI 1640 cell solution using in vitro high-frequency video microscopy every 60 s over a period of 15 min (min). Bepanthen^® solution and dexpanthenol in two clinically relevant concentrations (1.67% and 3.33%) were added to the cells. Addition of sterile water served as control group. To get a better overview, the measurements after 1 min, 5 min and 15 min were combined.

RESULTS

The CBF in the control group (n = 17) after 15 min was 7.3 ± 2.6 Hz. In comparison, the CBF after 15 min was 1.8 ± 1.0 Hz in the 3.33% Bepanthen^® group (n = 17) and 3.2 ± 1.2 Hz in the 1.67% group, which was statistically significantly lower in both groups (p < 0.001). With regard to the dexpanthenol group (n = 17) a CBF of 6.0 ± 2.6 Hz with 3.33% and 6.1 ± 2.4 Hz with 1.67% dexpanthenol, was detected, which was again statistically significantly lower (p = 0.06) compared to the control group except CBF at 15 min with 1.57% (n = 17; p = 0.04). In general, the effect on CBF was less pronounced with dexpanthenol compared with Bepanthen^® with a statistically significant difference between the two formulations. The results were verified by calculating an analysis of variance (ANOVA).

CONCLUSIONS

Bepanthen^® as an ointment, solution or inhalation is commonly used in ENT for mucosal care. Our results have shown that both substances reduce CBF in clinically relevant concentrations, although the effect was more pronounced with Bepanthen^® compared to dexpanthenol solution, which could be related to additives or change of physical properties in the solution. Further research is needed to assess potential clinical relevance.

Deep learning for the screening of primary ciliary dyskinesia based on cranial computed tomography

Objective: To analyze the cranial computed tomography (CT) imaging features of patients with primary ciliary dyskinesia (PCD) who have exudative otitis media (OME) and sinusitis using a deep learning model for early intervention in PCD.

Methods: Thirty-two children with PCD diagnosed at the Children’s Hospital of Fudan University, Shanghai, China, between January 2010 and January 2021 who had undergone cranial CT were retrospectively analyzed. Thirty-two children with OME and sinusitis diagnosed using cranial CT formed the control group. Multiple deep learning neural network training models based on PyTorch were built, and the optimal model was trained and selected to observe the differences between the cranial CT images of patients with PCD and those of general patients and to screen patients with PCD.

Results: The Swin-Transformer, ConvNeXt, and GoogLeNet training models had optimal results, with an accuracy of approximately 0.94; VGG11, VGG16, VGG19, ResNet 34, and ResNet 50, which are neural network models with fewer layers, achieved relatively strong results; and Transformer and other neural networks with more layers or neural network models with larger receptive fields exhibited a relatively weak performance. A heat map revealed the differences in the sinus, middle ear mastoid, and fourth ventricle between the patients with PCD and the control group. Transfer learning can improve the modeling effect of neural networks.

Conclusion: Deep learning-based CT imaging models can accurately screen for PCD and identify differences between the cranial CT images.

When should clinicians use the term syndrome?

Medical language provides essential communication with patients and among healthcare providers. Some words appear frequently in this communication, in clinical records, and in the medical literature, and the use of these words assumes that the listener and reader understand their meaning in the context related to their current use. Words, such as syndrome, disorder, and disease, should have obvious definitions but often, in fact, have uncertain meanings. In particular, the word syndrome should imply a definite and stable association between patient characteristics that have implications for treatment, prognosis, pathogenesis, and possibly clinical studies. In many cases the strength of this association is uncertain and the use of the word represents a convenient shorthand which may or may not improve communication with patients or other clinicians. Some astute clinicians have identified associations in their clinical practices, but this is a slow haphazard process. The development of electronic medical records, internet-based communication, and advanced statistical techniques has the potential to clarify important features of syndromes. However, the recent analysis of certain subsets of patients in the ongoing COVID-19 pandemic has demonstrated that even large amounts of information and advanced statistical techniques using clustering or machine learning may not provide precise separation of patients into groups. Clinicians should use the word syndrome carefully.

Schmidtea mediterranea as a Model Organism to Study the Molecular Background of Human Motile Ciliopathies

Cilia and flagella are evolutionarily conserved organelles that form protrusions on the surface of many growth-arrested or differentiated eukaryotic cells. Due to the structural and functional differences, cilia can be roughly classified as motile and non-motile (primary). Genetically determined dysfunction of motile cilia is the basis of primary ciliary dyskinesia (PCD), a heterogeneous ciliopathy affecting respiratory airways, fertility, and laterality. In the face of the still incomplete knowledge of PCD genetics and phenotype-genotype relations in PCD and the spectrum of PCD-like diseases, a continuous search for new causative genes is required. The use of model organisms has been a great part of the advances in understanding molecular mechanisms and the genetic basis of human diseases; the PCD spectrum is not different in this respect. The planarian model (Schmidtea mediterranea) has been intensely used to study regeneration processes, and-in the context of cilia-their evolution, assembly, and role in cell signaling. However, relatively little attention has been paid to the use of this simple and accessible model for studying the genetics of PCD and related diseases. The recent rapid development of the available planarian databases with detailed genomic and functional annotations prompted us to review the potential of the S. mediterranea model for studying human motile ciliopathies.

Primary Ciliary Dyskinesia in a Portuguese Bronchiectasis Outpatient Clinic

Primary ciliary dyskinesia (PCD) is a rare hereditary condition characterized by decreased mucociliary clearance of the airways and a compromised reproductive system, resulting in male and female infertility. Several mutations with varied clinical and pathological features have been documented, making diagnosis a challenging process. The purpose of this study is to describe the clinical and pathological features of Portuguese patients with PCD and to examine their genetic variants. A retrospective observational analysis was conducted with patients who were being monitored at a bronchiectasis outpatient clinic in 2022 and had a confirmed or high-likelihood diagnosis of PCD. In total, 17 patients were included in the study, with 12 (66.7%) having PCD confirmed and 5 (29.4%) having a high-likelihood diagnosis. Furthermore, 12 patients were subjected to transmission electron microscopy (TEM), with 7 (58.3%) exhibiting one hallmark defect. Genetic test data was obtained for all 17 patients, with 7 of them (41.2%) displaying a pathogenic/likely pathogenic mutation in homozygosity. To summarize, PCD is an uncommon but significant hereditary illness with consequences regarding morbidity and mortality. Despite the lack of a specific treatment, it is critical to confirm the diagnosis with genetic testing in order to effectively manage the disease and its accompanying disorders.

Lung Function in Children with Primary Ciliary Dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is characterized by impaired mucociliary clearance that results in accumulation of mucus and bacteria in the airways. Lower respiratory tract infections lead to airway remodeling and lung function impairment. The aim of our narrative review is to discuss available data on lung function in PCD children, focusing on risk factors for lung function impairment.

METHODS

Relevant published studies searching MEDLINE/Pubmed are included in this narrative review, using these terms: "primary ciliary dyskinesia" and "pulmonary function test" or "spirometry" or "lung function". Filters were language (English) and age of study subjects (0-18 years).

RESULTS AND CONCLUSIONS

The majority of recent published studies showed normal spirometric values in PCD children, even if some authors described a pulmonary impairment. Together with spirometry, Lung Clearance Index has been applied for detecting peripheral airway disease, and it might have a role in early mild lung disease assessment. Studies on lung function trajectories after PCD diagnosis showed a significant heterogeneity, with some patients maintaining reasonably good lung function, whereas others showing a decline. Further studies are needed to analyze lung function prospectively from childhood into adulthood, and to evaluate whether lung function trajectories are affected by PCD clinical phenotype, ultrastructural ciliary defect or genetic background.

In children with primary ciliary dyskinesia, which type of lung function test is the earliest determinant of decline in lung health: A systematic review

BACKGROUND

Primary ciliary dyskinesia is a rare genetic disorder characterized by recurrent sinopulmonary infections and worsening obstructive lung disease. Kidney and brain involvement is less common and is associated with overlapping ciliopathies/syndromes. The lungs are impacted early in the course of the disease, so it is vital to monitor lung function and recognize any decline by doing appropriate lung function tests. This systematic review compares different lung function tests and analyzes which one becomes abnormal earlier in the disease.

METHODS

A systematic review was conducted following the methodology in the "Cochrane Handbook on Systematic Reviews for diagnostic tests." The Preferred Reporting Items for Systematic Review and Meta-Analyses were used to report the results. The risk of bias assessment was done using "The Cochrane Handbook for Systematic Reviews tool for interventional studies." A meta-analysis was not performed due to the small sample size. All studies were analyzed by using Joanna Briggs Institute's critical appraisal tool.

RESULTS

After screening for the duplication of results and applying inclusion and exclusion criteria, 14 studies were assessed by reading the full texts. Out of these, eight were finally included in this systematic review. The total sample size from all studies was 165, including 80 males. All the studies used spirometry as a lung function test, whereas multiple breath washout was used in five studies. Other tests used for comparison were computed tomography (CT), magnetic resonance imaging (MRI), cardiopulmonary exercise testing, 6-min walk test, DLCO, maximal inspiratory pressure, maximal expiratory pressure, and PaO₂ . Lung clearance index (LCI) by multiple breath washout had a stronger association with the structural changes on CT/MRI than spirometry indices like forced expiratory volume in 1 s (FEV1) and forced expiratory flow at 25% to 75% of lung volume (FEF 25-75).

CONCLUSIONS

Based on the evidence from this systematic review, LCI becomes abnormal earlier than FEV1 or FEF 25-75 and positively correlates with the findings on high-resolution CT. It has limitations like the lack of reference values and a complex technique to perform the test.

Case report: The CCDC103 variant causes ultrastructural sperm axonemal defects and total sperm immotility in a professional athlete without primary ciliary diskinesia

Primary ciliary dyskinesia (PCD) is an inherited autosomal-recessive disorder characterized by abnormal ciliary motion, due to a defect in ciliary structure and/or function. This genetic condition leads to recurrent upper and lower respiratory infections, bronchiectasis, laterality defect, and subfertility. Male infertility is often associated with PCD, since the ultrastructure of the axoneme in the sperm tail is similar to that of the motile cilia of respiratory cells. We present the first reported case of a male patient from a non-consanguineous Italian family who exhibited a severe form of asthenozoospermia factor infertility but no situs inversus and absolutely no signs of the clinical respiratory phenotype, the proband being a professional basketball player. Whole-exome sequencing (WES) has identified a homozygote mutation (CCDC103 c.461 A>C, p.His154Pro) in the proband, while his brother was a heterozygous carrier for this mutation. Morphological and ultrastructural analyses of the axoneme in the sperm flagellum demonstrated the complete loss of both the inner and outer dynein arms (IDA and ODA, respectively). Moreover, immunofluorescence of DNAH1, which is used to check the assembly of IDA, and DNAH5, which labels ODA, demonstrated that these complexes are absent along the full length of the flagella in the spermatozoa from the proband, which was consistent with the IDA and ODA defects observed. Noteworthy, TEM analysis of the axoneme from respiratory cilia showed that dynein arms, although either IDAs and/or ODAs seldom missing on some doublets, are still partly present in each observed section. This case reports the total sperm immotility associated with the CCDC103 p.His154Pro mutation in a man with a normal respiratory phenotype and enriches the variant spectrum of ccdc103 variants and the associated clinical phenotypes in PCD, thus improving counseling of patients about their fertility and possible targeted treatments.

SARS-CoV-2 replication in airway epithelia requires motile cilia and microvillar reprogramming

How SARS-CoV-2 penetrates the airway barrier of mucus and periciliary mucins to infect nasal epithelium remains unclear. Using primary nasal epithelial organoid cultures, we found that the virus attaches to motile cilia via the ACE2 receptor. SARS-CoV-2 traverses the mucus layer, using motile cilia as tracks to access the cell body. Depleting cilia blocks infection for SARS-CoV-2 and other respiratory viruses. SARS-CoV-2 progeny attach to airway microvilli 24 h post-infection and trigger formation of apically extended and highly branched microvilli that organize viral egress from the microvilli back into the mucus layer, supporting a model of virus dispersion throughout airway tissue via mucociliary transport. Phosphoproteomics and kinase inhibition reveal that microvillar remodeling is regulated by p21-activated kinases (PAK). Importantly, Omicron variants bind with higher affinity to motile cilia and show accelerated viral entry. Our work suggests that motile cilia, microvilli, and mucociliary-dependent mucus flow are critical for efficient virus replication in nasal epithelia.

DNAH11 and a Novel Genetic Variant Associated with Situs Inversus: A Case Report and Review of the Literature

Background

Primary ciliary dyskinesia (PCD), also known as the immotile-cilia syndrome, is a clinically and genetically heterogeneous syndrome. Improper function of the cilia causes impaired mucociliary clearance. Neonatal respiratory distress, rhinosinusitis, recurrent chest infections, wet cough, and otitis media are respiratory presentations of this disease. It could also manifest as infertility in males as well as laterality defects in both sexes, such as situs abnormalities (Kartagener syndrome). During the past decade, numerous pathogenic variants in 40 genes have been identified as the causatives of primary ciliary dyskinesia. DNAH11 (dynein axonemal heavy chain 11) is a gene that is responsible for the production of cilia's protein and encodes the outer dynein arm. Dynein heavy chains are motor proteins of the outer dynein arms and play an essential role in ciliary motility. Case Presentation. A 3-year-old boy, the offspring of consanguineous parents, was referred to the pediatric clinical immunology outpatient department with a history of recurrent respiratory tract infections and periodic fever. Furthermore, on medical examination, situs inversus was recognized. His lab results revealed elevated levels of erythrocyte sedimentation rate (ESR) and C reactive protein (CRP). Serum IgG, IgM, and IgA levels were normal, while IgE levels were elevated. Whole exome sequencing (WES) was performed for the patient. WES demonstrated a novel homozygous nonsense variant in DNAH11 (c.5247G > A; p. Trp1749Ter).

Conclusion

We reported a novel homozygous nonsense variant in DNAH11 in a 3-year-old boy with primary ciliary dyskinesia. Biallelic pathogenic variants in one of the many coding genes involved in the process of ciliogenesis lead to PCD.

Flow blockage disrupts cilia-driven fluid transport in the epileptic brain

A carpet of ependymal motile cilia lines the brain ventricular system, forming a network of flow channels and barriers that pattern cerebrospinal fluid (CSF) flow at the surface. This CSF transport system is evolutionary conserved, but its physiological function remains unknown. Here we investigated its potential role in epilepsy with studies focused on CDKL5 deficiency disorder (CDD), a neurodevelopmental disorder with early-onset epilepsy refractory to seizure medications and the most common cause of infant epilepsy. CDKL5 is a highly conserved X-linked gene suggesting its function in regulating cilia length and motion in the green alga Chlamydomonas might have implication in the etiology of CDD. Examination of the structure and function of airway motile cilia revealed both the CDD patients and the Cdkl5 knockout mice exhibit cilia lengthening and abnormal cilia motion. Similar defects were observed for brain ventricular cilia in the Cdkl5 knockout mice. Mapping ependymal cilia generated flow in the ventral third ventricle (v3V), a brain region with important physiological functions showed altered patterning of flow. Tracing of cilia-mediated inflow into v3V with fluorescent dye revealed the appearance of a flow barrier at the inlet of v3V in Cdkl5 knockout mice. Analysis of mice with a mutation in another epilepsy-associated kinase, Yes1, showed the same disturbance of cilia motion and flow patterning. The flow barrier was also observed in the Foxj1^± and FOXJ1Cre^ERT:Cdkl5^y/fl mice, confirming the contribution of ventricular cilia to the flow disturbances. Importantly, mice exhibiting altered cilia-driven flow also showed increased susceptibility to anesthesia-induced seizure-like activity. The cilia-driven flow disturbance arises from altered cilia beating orientation with the disrupted polarity of the cilia anchoring rootlet meshwork. Together these findings indicate motile cilia disturbances have an essential role in CDD-associated seizures and beyond, suggesting cilia regulating kinases may be a therapeutic target for medication-resistant epilepsy.

Primary Ciliary Dyskinesia: Phenotype Resulting From a Novel Variant of LRRC56 Gene

Primary ciliary dyskinesia (PCD) involves cilia impairment, with resultant symptoms of repeated respiratory infections, sinusitis, and infertility. We report a seven-year-old boy of Arab ethnicity, with consanguineous parents, who was identified to have situs inversus totalis in neonatal life. There was a significant family history of ciliopathy as situs inversus totalis, infertility, and recurrent respiratory infections were noted in his two paternal uncles. From five months of age, the child started to have recurrent hospital visits due to respiratory infections. Infancy was marked by failure to thrive along with delay in achieving developmental milestones. Next-generation sequencing of known or potential ciliopathy genes revealed him homozygous for a novel mutation c.494T>C of the LRRC56 gene, thus defining PCD as a potential cause of his features.

Comprehensive overview of COVID-19-related respiratory failure: focus on cellular interactions

The pandemic outbreak of coronavirus disease 2019 (COVID-19) has created health challenges in all parts of the world. Understanding the entry mechanism of this virus into host cells is essential for effective treatment of COVID-19 disease. This virus can bind to various cell surface molecules or receptors, such as angiotensin-converting enzyme 2 (ACE2), to gain cell entry. Respiratory failure and pulmonary edema are the most important causes of mortality from COVID-19 infections. Cytokines, especially proinflammatory cytokines, are the main mediators of these complications. For normal respiratory function, a healthy air-blood barrier and sufficient blood flow to the lungs are required. In this review, we first discuss airway epithelial cells, airway stem cells, and the expression of COVID-19 receptors in the airway epithelium. Then, we discuss the suggested molecular mechanisms of endothelial dysfunction and blood vessel damage in COVID-19. Coagulopathy can be caused by platelet activation leading to clots, which restrict blood flow to the lungs and lead to respiratory failure. Finally, we present an overview of the effects of immune and non-immune cells and cytokines in COVID-19-related respiratory failure.

Case Report: DNAAF4 Variants Cause Primary Ciliary Dyskinesia and Infertility in Two Han Chinese Families

Background: Primary ciliary dyskinesia (PCD) is a rare genetic disorder, predominantly autosomal recessive. The dynein axonemal assembly factor 4 (DNAAF4) is mainly involved in the preassembly of multisubunit dynein protein, which is fundamental to the proper functioning of cilia and flagella. There are few reports of PCD-related pathogenic variants of DNAAF4, and almost no DNAAF4-related articles focused on sperm phenotype. Moreover, the association between DNAAF4 and scoliosis has never been reported, to the best of our knowledge.

Materials and Methods: We recruited two patients with a clinical diagnosis of PCD. One came from a consanguineous and another from a non-consanguineous family. Clinical data, laboratory test results, and imaging data were analyzed. Through whole exome sequencing, immunofluorescence, electron microscopy, high-speed video microscopy analysis, and hematoxylin–eosin (HE) staining, we identified the disease-associated variants and validated the pathogenicity.

Results: Proband 1 (P1, F1: II-1), a 19-year-old man, comes from a non-consanguineous family-I, and proband 2 (P2, F2: II-1), a 37-year-old woman, comes from a consanguineous family-II. Both had sinusitis, bronchiectasis, situs inversus, and scoliosis. P1 also had asthenoteratozoospermia, and P2 had an immature uterus. Two homozygous pathogenic variants in DNAAF4 (NM_130810.4), c.988C &gt; T, p.(Arg330Trp), and DNAAF4 (NM_130810.4), c.733 C &gt; T, p.(Arg245*), were identified through whole exome sequencing. High-speed microscopy analysis showed that most of the cilia were static in P1, with complete static of the respiratory cilia in P2. Immunofluorescence showed that the outer dynein arms (ODA) and inner dynein arms (IDA) were absent in the respiratory cilia of both probands, as well as in the sperm flagellum of P1. Transmission electron microscopy revealed the absence of ODA and IDA of respiratory cilia of P2, and HE staining showed irregular, short, absent, coiled, and bent flagella.

Conclusion: Our study identified a novel variant c.733C &gt; T, which expanded the spectrum of DNAAF4 variants. Furthermore, we linked DNAAF4 to asthenoteratozoospermia and likely scoliosis in patients with PCD. This study will contribute to a better understanding of PCD.

Primary ciliary dyskinesia and fungal infections: Two cases of allergic bronchopulmonary aspergillosis in children

Primary ciliary dyskinesia (PCD) is a rare inherited disease that affects the movement of the respiratory cilia. The main clinical manifestations are chronic upper and lower respiratory symptoms and recurrent lung infections, particularly bacterial and viral infections. Fungal infections are not usually associated with PCD. Allergic bronchopulmonary aspergillosis (ABPA) is a rare complex immune hypersensitivity reaction to Aspergillus fumigatus reported in patients with asthma and cystic fibrosis. Only three cases of ABPA associated with adult PCD have been described in the literature. Herein, we reported on two cases of ABPA in two boys aged 10 and 13 years with PCD. Both had severe lung disease and chronic Pseudomonas aeruginosa infections. One patient was diagnosed according to the typical clinical features of ABPA, while the other was diagnosed during a scheduled visit with no clinical changes but worsening pulmonary function and radiologic anomalies. The diagnosis of ABPA was confirmed in the two patients who then improved after receiving specific treatment. These two cases were the first to describe the occurrence of ABPA in children with PCD. We recommend that physicians involved in the management of children with PCD be aware of this potential complication.

Novel RSPH4A Variants Associated With Primary Ciliary Dyskinesia-Related Infertility in Three Chinese Families

Background: The radial spoke head component 4A (RSPH4A) is involved in the assembly of radial spokes, which is essential for motile cilia function. Asthenoteratozoospermia in primary ciliary dyskinesia (PCD) related to RSPH4A variants has not been reported. Materials and Methods: RSPH4A variants were identified and validated using whole-exome and Sanger sequencing in three unrelated Chinese families. High-speed video microscopy analysis (HSVA) was performed to measure the beating frequency and pattern of nasal cilia of the patients and healthy control. Papanicolaou staining and computer-aided sperm analysis were performed to analyze the morphology and motility of the sperm in patient 1. Immunofluorescence was adopted to confirm the structure deficiency of sperm and nasal cilia. Results: Patient 1 from family 1 is a 22-year-old unmarried male presented with bronchiectasis. Semen analysis and sperm Papanicolaou staining confirmed asthenoteratozoospermia. Novel compound heterozygous RSPH4A variants c.2T>C, p.(Met1Thr) and c.1774_1775del, p.(Leu592Aspfs*5) were detected in this patient. Patients 2 and 3 are from two unrelated consanguineous families; they are both females and exhibited bronchiectasis and infertility. Two homozygous RSPH4A variants c.2T>C, p.(Met1Thr) and c.351dupT, p.(Pro118Serfs*2) were detected, respectively. HSVA showed that most of the cilia in patients 1 and 3 were with abnormal rotational movement. The absence of RSPH4A and RSPH1 in patient 1's sperm and patient 3's respiratory cilia was indicated by immunofluorescence. Patient 2 died of pulmonary infection and respiratory failure at the age of 35 during follow-up. Conclusion: Dysfunctional sperm flagellum and motile cilia in the respiratory tract and the fallopian tube were found in patients with RSPH4A variants. Our study enriches the genetic spectrum and clinical phenotypes of RSPH4A variants in PCD, and c.2T>C, p.(Met1Thr) detected in our patients may be a hotspot RSPH4A variant in Chinese.

The disease-specific clinical trial network for Primary Ciliary Dyskinesia (PCD-CTN)

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by impaired mucociliary clearance leading to irreversible lung damage. In contrast to other rare lung diseases like cystic fibrosis (CF), there are only few clinical trials and limited evidence-based treatments. Management is mainly based on expert opinions and treatment is challenging due to a wide range of clinical manifestations and disease severity. To improve clinical and translational research and facilitate development of new treatments, the clinical trial network for PCD (PCD-CTN) was founded in 2020 under the framework of the European Reference Network (ERN)-LUNG PCD Core. Applications from European PCD sites interested in participating in the PCD-CTN were requested. Inclusion criteria consisted of patient numbers, membership of ERN-LUNG PCD Core, use of associated standards of care, experience in PCD and/or CF clinical research, resources to run clinical trials, good clinical practice (GCP) certifications and institutional support. So far, applications from 22 trial sites in 18 European countries have been approved, including >1400 adult and >1600 paediatric individuals with PCD. The PCD-CTN is headed by a coordinating centre and consists of a steering and executive committee, a data safety monitoring board and committees for protocol review, training and standardisation. A strong association with patient organisations and industrial companies are further cornerstones. All participating trial sites agreed on a code of conduct. As CTNs from other diseases have demonstrated successfully, this newly formed PCD-CTN operates to establish evidence-based treatments for this orphan disease and to bring new personalised treatment approaches to patients.

The disease-specific clinical trial network for primary ciliary dyskinesia (PCD-CTN) was built under the framework of the European Reference Network (ERN)-LUNG PCD Core, and operates to establish evidence-based and new personalised treatment for PCDhttps://bit.ly/3sLtC8o

Inhaled delivery of a lipid nanoparticle encapsulated messenger RNA encoding a ciliary protein for the treatment of primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a respiratory disease caused by dysfunction of the cilia with currently no approved treatments. This predominantly autosomal recessive disease is caused by mutations in any one of over 50 genes involved in cilia function; DNAI1 is one of the more frequently mutated genes, accounting for approximately 5-10% of diagnosed PCD cases. A codon-optimized mRNA encoding DNAI1 and encapsulated in a lipid nanoparticle (LNP) was administered to mice via aerosolized inhalation resulting in the expression human DNAI1 in the multiciliated cells of the pseudostratified columnar epithelia. The spatial localization of DNAI1 expression in the bronchioles indicate that delivery of the DNAI1 mRNA transpires the lower airways. In a PCD disease model, exposure to the LNP-encapsulated DNAI1 mRNA resulted in increased ciliary beat frequency using high speed videomicroscopy showing the potential for an mRNA therapeutic to correct cilia function in patients with PCD due to DNAI1 mutations.

A Novel Compound Heterozygous Mutation in the DNAH11 Gene Found in Neonatal Twins With Primary Ciliary Dyskinesis

Background: Primary ciliary dyskinesia (PCD) is a rare genetically heterogeneous disorder of motile cilia. Common features of PCD include upper and lower respiratory tract disease, secretory otitis media, situs inversus and fertility problems. To date, although several PCD-associated genes have been identified, the genetic causes of most PCD cases remain elusive.

Methods: In this case study, we analyzed the clinical and genetic data of one case of monochorionic diamniotic twins which were suspected of having PCD on the basis of clinical and radiological features including situs inversus, recurrent wet cough and sinusitis as well as varying degrees of respiratory distress. Whole-exome sequencing was performed to identify variants of the DNAH11 gene in the twins. Sanger sequencing and real-time quantitative polymerase chain reaction (RT-qPCR) were used for validation of DNAH11 variants both in the patient and the twins.

Results: In the twins, we found a novel mutation at c.2436C > G (p.Y812 *) and a pathogenic deletion encompassing 2.0 Kb of 7P15.3 ([GRCh38] chr7: g.21,816,397-21,818,402). The deleted region included exons 64 and 65 of DNAH11. Sanger sequencing also revealed that the twins’ father was a carrier of heterozygous C.2436C > G and a heterozygous deletion was detected in the mother. No other clinically relevant genetic variants were identified.

Conclusion: We describe a novel DNAH11 gene compound heterozygous mutation in newborn twins with PCD and recommend that PCD diagnosis should be considered in newborns presenting with respiratory distress and/or situs inversus. Early diagnosis and treatment of PCD will help control disease progression and improve the patient’s quality of life.

Paediatric asthma - all that wheezes is not necessarily asthma - current diagnostic and management strategies

PURPOSE OF REVIEW

Asthma is a frequently encountered chronic medical condition encountered in paediatrics, affecting 7% of children under the age of 18 in the United States. Although asthma is one of the more common conditions that is associated with wheezing, there is a broad differential diagnosis to consider. The purpose of this review is to describe other causes of wheezing outside of asthma in a paediatric population and discuss diagnostic and management strategies to consider when evaluating a child or adolescent with wheezing.

RECENT FINDINGS

The characteristics of the wheezing along with other associated signs and symptoms can be helpful in narrowing the differential diagnosis. The age and the past medical history of the patient are also important aspects to consider when determining next steps in the evaluation and management of paediatric wheezing. In addition to considering other causes of wheezing, it is often necessary to assess for the presence of underlying asthma, and recently updated asthma guidelines from the National Heart, Lung and Blood Institute provide a graded review of various recommendations for making the diagnosis and managing asthma in the clinical setting.

SUMMARY

It is important to maintain a broad differential diagnosis when evaluating a paediatric patient with wheezing.

Vestibular and Balance Impairment Is Common in Children With Primary Ciliary Dyskinesia

OBJECTIVE

Primary ciliary dyskinesia (PCD) is a rare genetic disorder that presents with a wide range of respiratory complaints. The most common otologic associated disorder is middle ear effusion. We ask if children with PCD suffer from vestibular impairment.

STUDY DESIGN

Cross-sectional cohort study.

SETTING

Tertiary pediatric referral hospital.

PATIENTS/PARTICIPANTS

Children with confirmed PCD.

INTERVENTION/METHODS

All included participants were clinically assessed to be at baseline then basic demographics and medical histories were collected, including the specific genetic mutation these patients have. After which, all patients underwent two vestibular tests. The first was to assess their ability to stand on one foot with their eyes open and then with their eyes closed and the second was video head impulse test (vHIT).

MAIN OUTCOME MEASURES

Ability standing on one foot with the eyes closed and vHIT.

RESULTS

During this period, 25 children with PCD were recruited for the study. The mean age at recruitment was 11.26 years (4-18 yr). There were 11 women and 14 men. All patients were able to participate in both tests. Nineteen participants (76%) had vestibular impairment. Fifteen of them failed to stand on one foot with their eyes closed and six of 25 had abnormal vHIT. The most common involved gene was DNAH5 8/25 (32%) and it was associated with vestibular impairment in seven of eight participants (87.5%).

CONCLUSION

The majority of children with PCD that we tested suffered from vestibular impairment that was previously undiagnosed. This potentially indicates that imbalance and vestibular pathology is under-diagnosed in children with PCD.