Clinical features and management of children with primary ciliary dyskinesia in England

Safety and efficacy of the epithelial sodium channel blocker idrevloride in people with primary ciliary dyskinesia (CLEAN-PCD): a multinational, phase 2, randomised, double-blind, placebo-controlled crossover trial

BACKGROUND

Mucociliary clearance is dysfunctional in people with primary ciliary dyskinesia, resulting in the accumulation of dehydrated mucus in the airways that is difficult to clear. We undertook a study to assess the benefit on lung function of treatment with a nebulised epithelial sodium channel (ENaC) blocker, idrevloride, with or without hypertonic saline, in people with primary ciliary dyskinesia.

METHODS

The CLEAN-PCD trial was a phase 2, randomised, double-blind, placebo-controlled crossover trial conducted at 32 tertiary adult and paediatric care centres and university hospitals in Canada, Denmark, Germany, Italy, the Netherlands, Poland, the UK, and the USA. People with a confirmed diagnosis of primary ciliary dyskinesia, aged 12 years or older, with a percentage of predicted FEV1 (ppFEV1) in the range of 40% to <90%, were randomly assigned in a 2:2:1:1 ratio (block size=6), stratified by ppFEV1 at screening, to one of four sequences: (1) idrevloride in hypertonic saline in treatment period 1 then hypertonic saline in treatment period 2; (2) hypertonic saline in treatment period 1 then idrevloride in hypertonic saline in treatment period 2; (3) idrevloride in treatment period 1 then placebo in treatment period 2; and (4) placebo in treatment period 1 then idrevloride in treatment period 2. The idrevloride dose was 85 μg and hypertonic saline was 4·2% NaCl. 3 mL of each study treatment was nebulised twice daily for 28 days in treatment periods 1 and 2; the two 28-day treatment periods were separated by a 28-day washout period. The primary endpoint was absolute change from baseline in ppFEV1 after 28 days. Safety assessments and reports of adverse events were made at clinic visits during each treatment period and by a follow-up telephone call 28 days after the last dose of study drug. Additionally, adverse events could be reported at a follow-up telephone call 3 days after the start of dosing and as they arose. Participants who received at least one dose of study drug were included in the safety analyses (safety set), and those who also had spirometry data were included in the efficacy analyses (full analysis set). The completed study is registered (EudraCT 2015-004917-26; ClinicalTrials.govNCT02871778).

FINDINGS

Between Sep 14, 2016, and May 31, 2018, 216 patients were screened and 123 were randomly assigned to one of four crossover sequences. Across the two treatment periods, treatment with idrevloride in hypertonic saline was initiated in 80 patients and completed in 78 patients (all 78 had data available and were included in the analysis); hypertonic saline initiated in 81 patients and completed in 76 patients (75 had data available and were included in the analysis); idrevloride initiated in 37 patients and completed in 35 patients (34 had data available and were included in the analysis); and placebo initiated in 36 patients and completed in 34 patients (all 34 had data available and were included in the analysis). Greater absolute increases in ppFEV1 from baseline to 28 days of treatment were seen with idrevloride in hypertonic saline (least-squares mean absolute change from baseline 1·0 percentage points, 95% CI -0·4 to 2·4) than with hypertonic saline alone (least-squares mean absolute change from baseline of -0·5 percentage points, -2·0 to 0·9; difference 1·5 percentage points, 95% CI <0·1 to 3·0; p=0·044). There was no significant difference in ppFEV1 for the parallel comparison of idrevloride in hypertonic saline compared with placebo or the crossover comparison of idrevloride with placebo. Adverse events were similar across treatments (57 to 65% of patients). Cough occurred in a greater proportion of participants during treatments that contained idrevloride or hypertonic saline compared with placebo, and oropharyngeal pain occurred in a greater proportion of participants during idrevloride treatments than during treatment with hypertonic saline alone or placebo, whereas chest discomfort was more common during treatments that included hypertonic saline.

INTERPRETATION

In this phase 2 crossover study, idrevloride in hypertonic saline was safe and associated with improved lung function over a 28-day period in people with primary ciliary dyskinesia compared with hypertonic saline alone. Larger, longer clinical studies are warranted to explore the potential benefits of idrevloride in combination with hypertonic saline in people with primary ciliary dyskinesia.

FUNDING

Parion Sciences, under agreement with Vertex Pharmaceuticals.

Ear and upper airway clinical outcome measures for use in primary ciliary dyskinesia research: a scoping review

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by pulmonary, otological and sino-nasal manifestations. Well-defined clinical outcome measures are needed in such rare diseases research to improve follow-up and treatments. Pulmonary outcome measures have recently been described. The aim of this study was to identify ear and upper airway outcome measures that could be used for longitudinal follow-up of individuals with PCD.

METHODS

A scoping review was performed by systematically searching MEDLINE, Embase and Cochrane Database of Systematic Reviews online databases for studies published from January 1996 to March 2022 that included at least 10 adult or paediatric PCD patients and reported ear and upper airway outcomes.

RESULTS

33 studies (1794 patients) were included. 10 ear and upper airway outcomes were reported. 17 studies reported audiometry, 16 reported otoscopic findings, and 13 reported rhinoscopic findings and sinus imaging. Health-related quality of life questionnaires were performed in seven studies. There was a high variability in definitions and measurement of outcomes between studies.

CONCLUSIONS

This scoping review highlights the lack of data regarding ear and upper airway outcomes in PCD. It also reports a high heterogeneity in outcome definitions or measures. We provide well-founded specific suggestions to standardise ear and upper airway outcome definitions and reporting for future PCD research studies.

Characteristics of Otologic Disease Among Patients With Primary Ciliary Dyskinesia

Importance

Otologic disease is common among people with primary ciliary dyskinesia (PCD), yet little is known about its spectrum and severity.

Objective

To characterize otologic disease among participants with PCD using data from the Ear-Nose-Throat Prospective International Cohort.

Design, Setting, and Participants

This cross-sectional analysis of baseline cohort data from February 2020 through July 2022 included participants from 12 specialized centers in 10 countries. Children and adults with PCD diagnoses; routine ear, nose, and throat examinations; and completed symptom questionnaires at the same visit or within 2 weeks were prospectively included.

Exposures

Potential risk factors associated with increased risk of ear disease.

Main Outcomes and Measures

The prevalence and characteristics of patient-reported otologic symptoms and findings from otologic examinations, including potential factors associated with increased risk of ear inflammation and hearing impairment.

Results

A total of 397 individuals were eligible to participate in this study (median [range] age, 15.2 [0.2-72.4] years; 186 (47%) female). Of the included participants, 204 (51%) reported ear pain, 110 (28%) reported ear discharge, and 183 (46%) reported hearing problems. Adults reported ear pain and hearing problems more frequently when compared with children. Otitis media with effusion-usually bilateral-was the most common otoscopic finding among 121 of 384 (32%) participants. Retracted tympanic membrane and tympanic sclerosis were more commonly seen among adults. Tympanometry was performed for 216 participants and showed pathologic type B results for 114 (53%). Audiometry was performed for 273 participants and showed hearing impairment in at least 1 ear, most commonly mild. Season of visit was the strongest risk factor for problems associated with ear inflammation (autumn vs spring: odds ratio, 2.40; 95% CI, 1.51-3.81) and age 30 years and older for hearing impairment (41-50 years vs ≤10 years: odds ratio, 3.33; 95% CI, 1.12-9.91).

Conclusion and Relevance

In this cross-sectional study, many people with PCD experienced ear problems, yet frequency varied, highlighting disease expression differences and possible clinical phenotypes. Understanding differences in otologic disease expression and progression during lifetime may inform clinical decisions about follow-up and medical care. Multidisciplinary PCD management should be recommended, including regular otologic assessments for all ages, even without specific complaints.

Sinonasal disease among patients with primary ciliary dyskinesia: an international study

Background

Sinonasal symptoms are a common feature of primary ciliary dyskinesia (PCD); however, literature about their severity and frequency, particularly during the life course, is scarce. Using baseline data from the Ear, nose and throat (ENT) Prospective International Cohort of PCD patients, we describe sinonasal disease in PCD.

Methods

We included participants who had a routine sinonasal examination during which they completed a symptoms questionnaire. We compared frequency of reported symptoms and examination findings among children and adults, and identified characteristics potentially associated with higher risk of sinonasal disease using ordinal regression.

Results

12 centres contributed 384 participants; median age was 16 years (IQR 9-22), and 54% were male. Chronic nasal problems were the most common feature, reported by 341 (89%). More adults (33; 24%) than children (10; 4%) described hyposmia. Quality of life was moderately affected by rhinosinusitis among 136 participants with completed SNOT-22 questionnaires (median score 31; IQR 23-45). Examinations revealed nasal polyps among 51 of 345 participants (15%) and hypertrophic inferior nasal turbinates among 127 of 341 participants (37%). Facial pain was detected in 50 of 342 participants (15%). Nasal polyps, hypertrophic turbinates, deviated septum and facial pain were found more commonly in adults than children. The only characteristic associated with higher risk of sinonasal disease was age 10 years and older.

Conclusions

Based on our findings, regular sinonasal examinations are relevant for patients with PCD of all ages. There is a need for improved management of sinonasal disease supported by evidence-based guidelines.

Using electrical impedance tomography to characterize lung impairment of children with primary ciliary dyskinesia: A pilot cross-sectional study

BACKGROUND

In children with primary ciliary dyskinesia (PCD), measures more sensitive than spirometry are needed to characterize underlying pulmonary impairment. Electrical impedance tomography (EIT) is a promising noninvasive method for monitoring the distribution of lung ventilation, and it does not require patient collaboration. We aimed to provide an assessment of the feasibility and clinical usefulness of EIT in characterizing lung impairment in children with PCD, compared to spirometry and multiple breath nitrogen washout (MBWN₂ ) test.

METHODS

Children and adolescents with PCD underwent MBWN₂ test as first respiratory assessment, followed by EIT monitoring and spirometry during outpatient follow-up.

RESULTS

We included 12 out of 16 individuals regularly followed at our clinic. A total of 41.7% (5/12) showed abnormal forced expiratory volume in 1 s (FEV₁ ), whereas 11/12 (91.7%) had abnormal ventilation inhomogeneity measured with MBWN₂ test. Using EIT, the global inhomogeneity (GI_TOT ) index showed moderate to strong correlation with FEV₁ (ρ = -0.55, 95% confidence interval [CI]: -0.87 to 0.02) and ranged from 37 to 44, with the highest inhomogeneity detected in the dorsal right quadrant. GI_TOT was moderately correlated with RV/TLC %predicted (ρ = 0.38, 95% CI: -0.17 to 0.74), while we detected a weak correlation between GI_TOT and lung clearance index (ρ = 0.29, 95% CI: -0.45 to 0.82).

CONCLUSION

EIT appears promising as a noninvasive technique to characterize ventilation distribution in children with PCD, thus providing a complementary assessment to static and dynamic lung function measures of PCD disease.

Revisiting Host-Pathogen Interactions in Cystic Fibrosis Lungs in the Era of CFTR Modulators

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators, a new series of therapeutics that correct and potentiate some classes of mutations of the CFTR, have provided a great therapeutic advantage to people with cystic fibrosis (pwCF). The main hindrances of the present CFTR modulators are related to their limitations in reducing chronic lung bacterial infection and inflammation, the main causes of pulmonary tissue damage and progressive respiratory insufficiency, particularly in adults with CF. Here, the most debated issues of the pulmonary bacterial infection and inflammatory processes in pwCF are revisited. Special attention is given to the mechanisms favoring the bacterial infection of pwCF, the progressive adaptation of Pseudomonas aeruginosa and its interplay with Staphylococcus aureus, the cross-talk among bacteria, the bronchial epithelial cells and the phagocytes of the host immune defenses. The most recent findings of the effect of CFTR modulators on bacterial infection and the inflammatory process are also presented to provide critical hints towards the identification of relevant therapeutic targets to overcome the respiratory pathology of pwCF.

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.

Psychological status of mothers of children with cystic fibrosis and primary ciliary dyskinesia

OBJECTIVES

We aimed to investigate depression, burnout, attitude, and burden of caregivers of children with cystic fibrosis (CF), and especially caregivers of children with primary ciliary dyskinesia (PCD) due to limited number of studies on this topic, and to compare them according to their children's clinical status.

METHODS

Clinical features and demographic data of children and their families were asked from caregivers in four pediatric pulmonology centers. Beck Depression Inventory, Maslach Burnout Inventory, Zarit Caregiver Burden Scale, and Parental Attitude Research Instrument were administered to caregivers in both groups. Results were compared between the two groups.

RESULTS

In total, 131 children with CF and 39 with PCD and their caregivers were involved in the study. All primary caregivers were mothers in both groups. Depression, burnout, and burden scores of mothers of children with CF were significantly higher than mothers of children with PCD (p = 0.017, p = 0.024, p = 0.038, respectively). Burnout was higher in both CF and PCD groups with low family income (p = 0.022, p = 0.034). Number of hospital visits in the previous 6 months was correlated with burnout in both CF and PCD groups (r = 0.207, p = 0.034; r = 0.352, p = 0.044).

CONCLUSIONS

Although mothers with children with CF have higher levels of depression, burnout, burden, and negative attitudes toward children than mothers with children with PCD, these are also significantly high in mothers with children with PCD. Psychological problems of mothers of children with CF and PCD may increase with frequent hospital visits, hospitalizations, low family income, number of children, and chronic disease in another child.

The Impact on Parents of Diagnosing PCD in Young Children

Primary ciliary dyskinesia (PCD) is an incurable, rare, inherited, chronic condition. Treatment includes the regular clearing of airway mucus, aggressive treatment of infections and management of hearing loss. Caregiver burden has not been explored, hence we interviewed 18 mothers and 6 fathers of children under 6 years to understand the impact of diagnostic testing and implications of a positive diagnosis. Interviews were transcribed and thematically analysed and five key themes were identified. These included the parents’ experiences following child’s diagnosis, impact of child’s treatment regimen on parent, impact of child’s health status on parent, parent’s coping strategies, and parental concerns for the future. Parents described their diagnostic journey, with the findings revealing how a lack of awareness among clinicians of the PCD symptom pattern can lead to a delayed diagnosis. Parents discussed the emotional and practical impact of a PCD diagnosis and the coping strategies employed to deal with challenges arising following a diagnosis. Parents use a variety of different lifestyle changes to accommodate their child’s treatment regimen and to cope with disruptive life events such as the COVID-19 pandemic. This study provides valuable insights into parental adjustment and adaptation to a PCD diagnosis and management regimen. Going forward, this research highlights the need for integrated social care for PCD patients and their families.

Chronic airway disease in primary ciliary dyskinesia—spiced with geno–phenotype associations

Primary ciliary dyskinesia (PCD) can be defined as a multiorgan ciliopathy with a dominant element of chronic airway disease affecting the nose, sinuses, middle ear, and in particular, the lower airways. Although most patients with PCD are diagnosed during preschool years, it is obvious that the chronic lung disease starts its course already from birth. The many faces of the clinical picture change, as does lung function, structural lung damage, the burden of infection, and of treatment throughout life. A markedly severe neutrophil inflammation in the respiratory tract seems pervasive and is only to a minimal extent ameliorated by a treatment strategy, which is predominantly aimed at bacterial infections. An ever‐increasing understanding of the different aspects, their interrelationships, and possible different age courses conditioned by the underlying genotype is the focus of much attention. The future is likely to offer personalized medicine in the form of mRNA therapy, but to that end, it is of utmost importance that all patients with PCD be carefully characterized and given a genetic diagnosis. In this narrative review, we have concentrated on lower airways and summarized the current understanding of the chronic airway disease in this motile ciliopathy. In addition, we highlight the challenges, gaps, and opportunities in PCD lung disease research.

Facemask Usage Among People With Primary Ciliary Dyskinesia During the COVID-19 Pandemic: A Participatory Project

Objectives: Primary ciliary dyskinesia (PCD) is a rare genetic disease that causes recurrent respiratory infections. People with PCD may be at high risk of severe COVID-19 and protection against SARS-CoV-2 is therefore important. We studied facemask usage and problems reported in relation with their use among people with PCD. Methods: We used data from COVID-PCD, an international observational cohort study. A questionnaire was e-mailed to participants in October 2020 that asked about facemask usage. Results: In total, 282 participants from 27 countries were included (Median age 32 years; 63% female). In total, 252 (89%) wore facemasks everywhere in public, 13 (5%) wore facemasks in most places, and 17 (6%) did not wear facemasks in public. Half of the participants reported that it was uncomfortable to wear facemasks because of runny nose, cough, or difficulty breathing. Participants less often wore facemasks when there was no national requirement. Conclusion: Most people with PCD wore facemasks despite frequent respiratory problems related to their use. Facemask usage was most frequent in countries with a national requirement emphasizing the importance of nationwide policies mandating facemasks.

Long-Term Azithromycin Treatment in Pediatric Primary Ciliary Dyskinesia: A Retrospective Study

OBJECTIVES

Primary ciliary dyskinesia (PCD) is a rare genetic disease mainly involved in lung dysfunction. PCD patient outcomes after azithromycin (AZM) treatment have rarely been reported. This study was aimed to assess AZM treatment effects on disease progression of pediatric PCD patients.

STUDY DESIGN

This retrospective follow-up study involved PCD patients diagnosed from 2009 to 2021. Changes of clinical outcomes, pulmonary function, and chest computed tomography findings were compared between untreated and AZM-treated patients.

RESULTS

Of 71 enrolled patients (median follow-up duration of 3.1 years), 34 received AZM (AZM-treated group) and 37 received no AZM (AZM-untreated group). At diagnosis, no significant intergroup differences in age, sex, height, weight, number of respiratory exacerbations, and FEV1% and FVC% predicted values were found, although FEF_25-75% predicted was lower in AZM-treated group. Between treatment initiation and follow-up, patients in AZM-treated group had less respiratory exacerbations than that of AZM-untreated group (mean ± SD, 1.4 ± 0.8 vs. 3.0 ± 2.1, times/year P = 0.001) and fewer AZM-treated group patients exhibited exercise intolerance. Increases above baseline of AZM-treated FEV1% and FVC% predicted values exceeded that of AZM-untreated group, but intergroup differences were insignificant (FEV1% predicted: (median, IQR) 5.3 [-13.4, 9.4] vs. 1.8 [-12.1, 9.5], P = 0.477; FVC% predicted: (median, IQR) 6.7 [-7.6, 18.8] vs. 1.6 [-5.6, 7.6], P = 0.328).

CONCLUSION

Long-term AZM treatment can reduce respiratory infection frequency and may maintain pulmonary diseases stable in pediatric PCD patients with worse lung function.

COVID-19 Vaccinations: Perceptions and Behaviours in People with Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a rare genetic disease that causes recurrent respiratory infections. People with PCD may be at higher risk of severe coronavirus disease 2019 (COVID-19), and therefore vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important. We studied vaccination willingness, speed of vaccination uptake, side effects, and changes in social contact behaviour after vaccination in people with PCD. We used data from COVID-PCD, an international participatory cohort study. A COVID-19 vaccination questionnaire was emailed to participants in May 2021 and 423 participants from 31 countries replied (median age: 30 years, range 1-85 years; 261 (62%) female). Vaccination uptake and willingness were high, with 273 of 287 adults (96%) being vaccinated or willing to be in June 2021; only 4% were hesitant. The most common reason for hesitancy was fear of side effects, reported by 88%. Mild side effects were common, but no participant reported severe side effects. Half of the participants changed their social behaviour after vaccination by seeing friends and family more often. The high vaccination willingness in the study population might reflect the extraordinary effort taken by PCD support groups to inform people about COVID-19 vaccination. Clear and specific information and involvement of representatives is important for high vaccine uptake.

Evaluation of age at diagnosis and clinical findings of children with primary ciliary dyskinesia

OBJECTIVE

Patients with primary ciliary dyskinesia (PCD) may present with different clinical findings at different ages, and age at diagnosis may differ. We aimed to review clinical factors that affected age at diagnosis of patients with PCD.

STUDY DESIGN

All 70 patients with PCD who were followed in our pediatric pulmonology department were included. Demographic features, clinical findings, PrImary CiliAry DyskinesiA Rule (PICADAR) scores and pulmonary function tests of patients were recorded and clinical factors that affected age at diagnosis were evaluated.

RESULTS

The mean age at diagnosis was 8.3 ± 4.6 years. Most of patients (95.7%) had a persistent wet cough. The mean PICADAR score was 6.5 ± 3.2, and there was a negative correlation between PICADAR and age at diagnosis (r = -0.271, p = .023). The mean ages at diagnosis of patients with situs abnormality and recurrent wheezing were earlier than in patients without situs abnormality and recurrent wheezing (6.7 ± 4.3 and 6.8 ± 4.3, p = .002 vs. 9.8 ± 4.3 and 9.0 ± 4.6 years, p = .040, respectively). The mean age at diagnosis of patients with bronchiectasis was later than in patients without bronchiectasis (10.8 ± 3.9 and 6.9 ± 4.4 years, p = .001). Other clinical features were not statistically significant according to age at diagnosis (p > .05). There was no statistically significant relation between age at diagnosis and sex, sibling or relative with PCD and parental consanguinity (p > .05).

CONCLUSION

Although most patients diagnosed with PCD had symptoms, the diagnosis may be delayed. High PICADAR score is a useful guide to evaluate PCD. Situs abnormality and recurrent wheezing could be clues for early diagnosis of PCD. Early diagnosis of PCD may prevent bronchiectasis.

Progress in Diagnosing Primary Ciliary Dyskinesia: The North American Perspective

Primary Ciliary Dyskinesia (PCD) is a rare, under-recognized disease that affects respiratory ciliary function, resulting in chronic oto-sino-pulmonary disease. The PCD clinical phenotype overlaps with other common respiratory conditions and no single diagnostic test detects all forms of PCD. In 2018, PCD experts collaborated with the American Thoracic Society (ATS) to create a clinical diagnostic guideline for patients across North America, specifically considering the local resources and limitations for PCD diagnosis in the United States and Canada. Nasal nitric oxide (nNO) testing is recommended for first-line testing in patients ≥5 years old with a compatible clinical phenotype; however, all low nNO values require confirmation with genetic testing or ciliary electron micrograph (EM) analysis. Furthermore, these guidelines recognize that not all North American patients have access to nNO testing and isolated genetic testing is appropriate in cases with strong clinical PCD phenotypes. For unresolved diagnostic cases, referral to a PCD Foundation accredited center is recommended. The purpose of this narrative review is to provide insight on the North American PCD diagnostic process, to enhance the understanding of and adherence to current guidelines, and to promote collaboration with diagnostic pathways used outside of North America.

SARS-CoV-2 infections in people with primary ciliary dyskinesia: neither frequent, nor particularly severe

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had by March 2021 infected ≥115 million people worldwide and caused >2.5 million deaths. People with pre-existing chronic health conditions are reportedly at high risk of catching the disease and of having a severe disease course [1–4]. Primary ciliary dyskinesia (PCD) is a multisystem, genetic disease which affects approximately 1 in 10 000 people and leads to chronic upper and lower airway disease, laterality defects, including congenital heart disease, and other health problems [5–8]. In March 2020, PCD patient support groups contacted the paediatric respiratory research group at the University of Bern (Bern, Switzerland) with the wish to set up a study that generates evidence on the risk and evolution of COVID-19 in people with PCD. This led to the launch of COVID-PCD, a longitudinal online survey of health, shielding behaviours and quality of life of people with PCD during the pandemic. COVID-PCD is a participatory study that collects data in real-time directly from people with PCD using online questionnaires. This article provides the first data on risk and severity of SARS-CoV-2 infections among study participants for the time period between 30 May 2020 and 5 March 2021.

In this longitudinal study of people with PCD followed weekly via online questionnaires, the incidence rate of COVID-19 and the proportion of participants infected were low, and the observed severity mostly mildhttps://bit.ly/3frKICr

COVID-PCD: a participatory research study on the impact of COVID-19 in people with primary ciliary dyskinesia

COVID-PCD is a participatory study initiated by people with primary ciliary dyskinesia (PCD) who have an essential vote in all stages of the research from the design of the study to the recruitment of participants, and interpretation and communication of the study results. COVID-PCD aims to collect epidemiological data in real-time from people with PCD throughout the pandemic to describe incidence of coronavirus disease 2019 (COVID-19), symptoms and course of disease; identify risk factors for prognosis; and assess experiences, wishes and needs. The study is advertised through patient support groups and participants register online on the study website (www.covid19pcd.ispm.ch). The study invites persons of any age from anywhere in the world with a suspected or confirmed PCD. A baseline questionnaire assesses details on PCD diagnosis, habitual symptoms and COVID-19 episodes that occurred before study entry. Afterwards, participants receive a weekly follow-up questionnaire with questions on incident severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, current symptoms, social contact behaviour and physical activity. Occasional thematic questionnaires are sent out focussing on emerging questions of interest chosen by people with PCD. In case of hospitalisation, patients or family members are asked to obtain a hospital report. Results are continuously analysed and summaries put online. The study started recruitment on April 30, 2020, and 556 people with PCD completed the baseline questionnaire by November 2, 2020. The COVID-PCD study is a participatory study that follows people with PCD during the COVID-19 pandemic, helps to empower affected persons, and serves as a platform for communication between patients, physicians and researchers.

Motile ciliopathies

Motile cilia are highly complex hair-like organelles of epithelial cells lining the surface of various organ systems. Genetic mutations (usually with autosomal recessive inheritance) that impair ciliary beating cause a variety of motile ciliopathies, a heterogeneous group of rare disorders. The pathogenetic mechanisms, clinical symptoms and severity of the disease depend on the specific affected genes and the tissues in which they are expressed. Defects in the ependymal cilia can result in hydrocephalus, defects in the cilia in the fallopian tubes or in sperm flagella can cause female and male subfertility, respectively, and malfunctional motile monocilia of the left-right organizer during early embryonic development can lead to laterality defects such as situs inversus and heterotaxy. If mucociliary clearance in the respiratory epithelium is severely impaired, the disorder is referred to as primary ciliary dyskinesia, the most common motile ciliopathy. No single test can confirm a diagnosis of motile ciliopathy, which is based on a combination of tests including nasal nitric oxide measurement, transmission electron microscopy, immunofluorescence and genetic analyses, and high-speed video microscopy. With the exception of azithromycin, there is no evidence-based treatment for primary ciliary dyskinesia; therapies aim at relieving symptoms and reducing the effects of reduced ciliary motility.