Primary Ciliary Dyskinesia Patients Research Articles

Ccdc103 promotes myeloid cell proliferation and migration independent of motile cilia.

ABSTRACTThe pathology of primary ciliary dyskinesia (PCD) is predominantly attributed to impairment of motile cilia. However, PCD patients also have perplexing functional defects in myeloid cells, which lack motile cilia. Here, we show that coiled-coil domain-containing protein 103 (CCDC103), one of the genes that, when mutated, is known to cause PCD, is required for the proliferation and directed migration of myeloid cells. CCDC103 is expressed in human myeloid cells, where it colocalizes with cytoplasmic microtubules. Zebrafish ccdc103/schmalhans (smh) mutants have macrophages and neutrophils with reduced proliferation, abnormally rounded cell morphology and an inability to migrate efficiently to the site of sterile wounds, all of which are consistent with a loss of cytoplasmic microtubule stability. Furthermore, we demonstrate that direct interactions between CCDC103 and sperm associated antigen 6 (SPAG6), which also promotes microtubule stability, are abrogated by CCDC103 mutations from PCD patients, and that spag6 zebrafish mutants recapitulate the myeloid defects observed in smh mutants. In summary, we have illuminated a mechanism, independent of motile cilia, to explain functional defects in myeloid cells from PCD patients.This article has an associated First Person interview with the first author of the paper.

Higher throughput drug screening for rare respiratory diseases: readthrough therapy in primary ciliary dyskinesia.

BackgroundDevelopment of therapeutic approaches for rare respiratory diseases is hampered by the lack of systems that allow medium-to-high-throughput screening of fully differentiated respiratory epithelium from affected patients. This is a particular problem for primary ciliary dyskinesia (PCD), a rare genetic disease caused by mutations in genes that adversely affect ciliary movement and consequently mucociliary transport. Primary cell culture of basal epithelial cells from nasal brush biopsies followed by ciliated differentiation at the air–liquid interface (ALI) has proven to be a useful tool in PCD diagnostics but the technique's broader utility, including in pre-clinical PCD research, has been restricted by the limited number of basal cells that can be expanded from such biopsies.MethodsWe describe an immunofluorescence screening method, enabled by extensive expansion of basal cells from PCD patients and the directed differentiation of these cells into ciliated epithelium in miniaturised 96-well transwell format ALI cultures. As proof-of-principle, we performed a personalised investigation in a patient with a rare and severe form of PCD (reduced generation of motile cilia), in this case caused by a homozygous nonsense mutation in the MCIDAS gene.ResultsInitial analyses of ciliary ultrastructure, beat pattern and beat frequency in the 96-well transwell format ALI cultures indicate that a range of different PCD defects can be retained in these cultures. The screening system in our proof-of-principal investigation allowed drugs that induce translational readthrough to be evaluated alone or in combination with nonsense-mediated decay inhibitors. We observed restoration of basal body formation but not the generation of cilia in the patient's nasal epithelial cells in vitro.ConclusionOur study provides a platform for higher throughput analyses of airway epithelia that is applicable in a range of settings and suggests novel avenues for drug evaluation and development in PCD caused by nonsense mutations.

77680 Nasal Nitric Oxide Levels as a Diagnostic Tool for Primary Ciliary Dyskinesia in Puerto Rico

ABSTRACT IMPACT: The implementation of nasal nitric oxide (nNO) as a diagnostic tool to understand the phenotypic/genotypic profiles of Primary Ciliary Dyskinesia (PCD) in Puerto Rico (PR) will be translated in early disease diagnosis, avoidance of comorbidities, and increase survival in our population. OBJECTIVES/GOALS: This study aims to evaluate the role of nNO levels in PCD diagnosis in the Puerto Rican population. Also, we aim to describe the clinical, genetic, and physiological characteristics of PCD in Puerto Ricans to develop a better understanding of the disease. METHODS/STUDY POPULATION: We plan to conduct a cross-sectional study on participants recruited from patients of the Pediatric Rare Lung and Asthma Institute in PR. We will compare nNO levels among genetically confirmed PCD patients, suspected PCD patients with variant of unknown significance (VUS) mutations, suspected PCD patients without genetic mutations, and age-matched healthy subjects. We plan to analyze clinical data and genetic variants to understand the natural history of the disease. The nNO measurements will be completed following previous published protocols. We will also assess the accuracy of the nNO measurements by repeating the measurements two weeks after the initial measurement. RESULTS/ANTICIPATED RESULTS: We hypothesize that many of the VUS present in our population may represent potential new founder mutations not previously reported in the literature. Our expectation is to identify new atypical PCD phenotypes contemplating the heterogenous genetic Puerto Rican pool. We anticipate that nNO levels will help to screen, identify, and confirm diagnosis of patients with clinical PCD in PR. Our findings will be translated in avoidance of further comorbidities and mortality due to earlier disease PCD diagnosis and will expand our genetic understanding about PCD in PR and other diverse populations with heterogenous genetic admixture. DISCUSSION/SIGNIFICANCE OF FINDINGS: We present a significant and novel research proposal that plan to impact the quality of life of patients living with PCD in PR. The implementation of state-of-the-art diagnostic tools like nNO measurement will positively impact and expand our current capabilities to diagnose rare lung diseases like PCD on the island.

Defects in the cytoplasmic assembly of axonemal dynein arms cause morphological abnormalities and dysmotility in sperm cells leading to male infertility.

Axonemal protein complexes, such as outer (ODA) and inner (IDA) dynein arms, are responsible for the generation and regulation of flagellar and ciliary beating. Studies in various ciliated model organisms have shown that axonemal dynein arms are first assembled in the cell cytoplasm and then delivered into axonemes during ciliogenesis. In humans, mutations in genes encoding for factors involved in this process cause structural and functional defects of motile cilia in various organs such as the airways and result in the hereditary disorder primary ciliary dyskinesia (PCD). Despite extensive knowledge about the cytoplasmic assembly of axonemal dynein arms in respiratory cilia, this process is still poorly understood in sperm flagella. To better define its clinical relevance on sperm structure and function, and thus male fertility, further investigations are required. Here we report the fertility status in different axonemal dynein preassembly mutant males (DNAAF2/ KTU, DNAAF4/ DYX1C1, DNAAF6/ PIH1D3, DNAAF7/ZMYND10, CFAP300/C11orf70 and LRRC6). Besides andrological examinations, we functionally and structurally analyzed sperm flagella of affected individuals by high-speed video- and transmission electron microscopy as well as systematically compared the composition of dynein arms in sperm flagella and respiratory cilia by immunofluorescence microscopy. Furthermore, we analyzed the flagellar length in dynein preassembly mutant sperm. We found that the process of axonemal dynein preassembly is also critical in sperm, by identifying defects of ODAs and IDAs in dysmotile sperm of these individuals. Interestingly, these mutant sperm consistently show a complete loss of ODAs, while some respiratory cilia from the same individual can retain ODAs in the proximal ciliary compartment. This agrees with reports of solely one distinct ODA type in sperm, compared to two different ODA types in proximal and distal respiratory ciliary axonemes. Consistent with observations in model organisms, we also determined a significant reduction of sperm flagellar length in these individuals. These findings are relevant to subsequent studies on the function and composition of sperm flagella in PCD patients and non-syndromic infertile males. Our study contributes to a better understanding of the fertility status in PCD-affected males and should help guide genetic and andrological counselling for affected males and their families.

The effect of a novel LRRC6 mutation on the flagellar ultrastructure in a primary ciliary dyskinesia patient

There are limited genes known to cause primary ciliary dyskinesia (PCD)-associated asthenozoospermia. In the present study, we aimed to expand the spectrum of mutations in PCD and to provide new information for genetic counseling diagnoses and the treatment of male infertility in PCD. One sterile patient with typical situs inversus was recruited to our center, and semen sample was collected. We performed whole-exome sequencing (WES) on the patient to identify the pathogenic mutations associated with PCD and used transmission electron microscopy to investigate spermatozoal ultrastructure. In addition, western blotting and immunofluorescence staining were used to confirm the untoward impact of the variant on the expression of LRRC6, as well as on the dynein arm proteins in the patient's spermatozoa. We identified a homozygous nonsense variant c.749G>A (p.W250*) of LRRC6 in the PCD patient. This variant severely impaired LRRC6 expression and further led to negative effects on dynein arm protein expression in the spermatozoa of the affected individual, which eventually caused defects in sperm ultrastructure and motility. Moreover, we are the first to report a positive prognosis using intracytoplasmic sperm injection (ICSI) for LRRC6-associated male infertility. Our findings strongly implicated the homozygous mutation of c.749G>A (p.W250*) in LRRC6 as a new genetic cause of PCD, uncovering its involvement in defective sperm flagella and poor sperm motility. Furthermore, we posit that patients with LRRC6 mutations may have good outcomes with ICSI treatment. These findings add to the literature on the genetic diagnoses and treatment of male infertility associated with PCD.

IFT46 Expression in the Nasal Mucosa of Primary Ciliary Dyskinesia Patients: Preliminary Study.

BackgroundPrimary ciliary dyskinesia (PCD) is characterised by an imbalance in mucociliary clearance leading to chronic respiratory infections. Cilia length is considered to be a contributing factor in cilia movement. Recently, IFT46 protein has been related to cilia length. Therefore, this work aims to study IFT46 expression in a PCD patients cohort and analyse its relationship with cilia length and function, as it was not previously described.Materials and methodsThe expression of one intraflagellar transport (IFT46) and two regulating ciliary architecture (FOXJ1 and DNAI2) genes, as well as cilia length of 27 PCD patients, were measured. PCD patients were diagnosed based on clinical data, and cilia function and ultrastructure. Gene expression was estimated by real-time RT-PCR and cilia length by electron microscopy in nasal epithelium biopsies.Results and conclusions: While IFT46 expression was only diminished in patients with short cilia, FOXJ1, and DNAI2 expression were reduced in all PCD patient groups compared to controls levels. Among the PCD patients, cilia were short in 44% (5.9 ± 0.70 µm); nine of these (33% from the total) patients’ cilia also had an abnormal ultrastructure. Cilia length was normal in 33% of patients (6.4 ± 0.39 µm), and only three patients’ biopsies indicated decreased expression of dynein.

A retrospective review of Achromobacter species and antibiotic treatments in patients with primary ciliary dyskinesia.

Objectives: Primary ciliary dyskinesia (PCD) is a rare congenital disease with defective mucociliary clearance causing frequent and often persistent pulmonary infections. Achromobacter species are opportunistic pathogens renowned for the difficulty of effective treatments and deteriorating effects on lung function. We aimed to describe the occurrence, treatment, and rate of successful eradication of Achromobacter species in patients with PCD. Methods: We retrospectively reviewed 18 years of historical microbiological samples and 10 years of electronic health records for PCD patients in Denmark. Results: We included 136 patients. Twenty-six patients had isolates of Achromobacter species. On average, 5% of the cohort had at least one annual isolate. Infections became persistent in 38% with a median length of 6.6 years leading to a significant number of antibiotic treatments. Resistance toward tobramycin and ciprofloxacin was prevalent. Overall, successful eradication was achieved in 62% of patients. We found the course of lung function significantly worse during persistent Achromobacter species infection than during the two preceding years, but not different to the course in unaffected age-matched controls. Conclusion The prevalence of Achromobacter species in patients with PCD is in line with what has been reported in cystic fibrosis and can occur transiently, intermittently, or develop into a serious persistent lung infection associated with long-term antibiotic treatment.

CiliarMove: new software for evaluating ciliary beat frequency helps find novel mutations by a Portuguese multidisciplinary team on primary ciliary dyskinesia.

Evaluation of ciliary beat frequency (CBF) performed by high-speed videomicroscopy analysis (HVMA) is one of the techniques required for the correct diagnosis of primary ciliary dyskinesia (PCD). Currently, due to lack of open-source software, this technique is widely performed by visually counting the ciliary beatings per a given time-window. Our aim was to generate open-source, fast and intuitive software for evaluating CBF, validated in Portuguese PCD patients and healthy volunteers.Nasal brushings collected from 17 adult healthy volunteers and 34 PCD-referred subjects were recorded using HVMA. Evaluation of CBF was compared by two different methodologies: the new semi-automated computer software CiliarMove and the manual observation method using slow-motion movies. Clinical history, nasal nitric oxide and transmission electron microscopy were performed for diagnosis of PCD in the patient group. Genetic analysis was performed in a subset (n=8) of suspected PCD patients.The correlation coefficient between the two methods was R2=0.9895. The interval of CBF values obtained from the healthy control group (n=17) was 6.18–9.17 Hz at 25°C. In the PCD-excluded group (n=16), CBF ranged from 6.84 to 10.93 Hz and in the PCD group (n=18), CBF ranged from 0 to 14.30 Hz.We offer an automated open-source programme named CiliarMove, validated by the manual observation method in a healthy volunteer control group, a PCD-excluded group and a PCD-confirmed group. In our hands, comparisons between CBF intervals alone could discern between healthy and PCD groups in 78% of the cases.

The Usefulness of a Transbronchial Lung Cryobiopsy for Diffuse Bronchiolitis.

We herein report four cases of diffuse bronchiolitis proven by a transbronchial lung cryobiopsy (TBLC). Based on various aspects, including the pathological findings, we definitively diagnosed two patients with diffuse panbronchiolitis (DPB) and the other two with primary ciliary dyskinesia (PCD). One of the DPB patients had more severe peribronchiolar fibrosis than the other, and the disease course was refractory to macrolide therapy. One of the PCD patients was additionally diagnosed with combined constrictive bronchiolitis. This report highlights the importance of a TBLC in the differentiation of bronchiolitis, suggesting its utility for helping pulmonologists formulate a treatment strategy.

Bi-allelic variant c.8638_8658dup in HYDIN causes bronchiectasis in two siblings

• Bi-allelic loss-of-function variants in HYDIN cause Primary Ciliary Dyskinesia (PCD) • The PCD patients presented with respiratory distress, chronic cough, bronchitis, and rhino-sinusitis • Exome sequencing identified a novel bi-allelic variant c.8638_8658dup in HYDIN in siblings with bronchiectasis • Next-generation sequencing would benefit PCD patients since early and accurate diagnosis • Accurate diagnosis facilitates early intervention of preventive respiratory care and definitive genetic counseling

Is Quarantine for COVID-19 Pandemic Associated with Psychological Burden in Primary Ciliary Dyskinesia?

Background: Information on psychological impact of COVID-19 quarantine in primary ciliary dyskinesia (PCD), a chronic disorder with recurrent pulmonary exacerbations, is lacking. Psychological well-being was prospectively assessed during COVID-19 lockdown in Italy in a PCD population. Methods: we recruited 27 PCD patients and 27 healthy controls. To assess psychological well-being, psychological general well-being index and parenting stress index-short questionnaires were administered to participants ≥15 years-old and to mothers of participants <15 years-old, respectively. The PCD exacerbations since outbreak onset and frequency of quarantine weekly chest physiotherapy were compared to the same period of 2019. Outcomes: 70% of PCD mothers and 90% of PCD patients did not show parental stress levels or distress levels, respectively, and these groups showed no significant difference in stress compared to controls. The PCD pulmonary exacerbations occurred less frequently and weekly chest physiotherapy sessions significantly increased compared to the same period during 2019 (p < 0.05). Interpretation: During COVID-19 quarantine, a PCD population showed psychological well-being. Low exacerbation rate, explained by lower infectious exposure or improved compliance to chest physiotherapy, likely contributed to psychological well-being. Evaluating psychological burden and parental stress is a valuable tool for measuring the emotional impact of PCD and improving PCD medical care.

Comparison of conventional chest physiotherapy and oscillatory positive expiratory pressure therapy in primary ciliary dyskinesia

Chest physiotherapy (CP) is a recommended treatment modality in primary ciliary dyskinesia (PCD). Primary aim was to compare the efficacy and safety of the conventional chest physiotherapy (CCP) and oscillatory positive expiratory pressure therapy (OPEPT). Secondary aims were to compare the exacerbation rate, time until the first exacerbation, patient compliance and comfort between the two CP methods. This is a 6 month randomized, controlled crossover trial. Patients >6 years of age with PCD were randomized into two groups, first group was assigned to OPEPT (Acapella®) for 3 months while second group was assigned to CCP. Groups were crossed over to the other modality after a 15-day washout period. Pulmonary function tests (PFTs) and compliance were monitored by monthly clinic visits. There was a significant increase in FEV1 , FEF25-75 , and PEF values (p = .018, p = .020, and p = .016, respectively) in the OPEPT group and in FVC values (p = .007) in CCP group compared to baseline. However PFT increase at 3rd month was not superior to each other with both physiotherapy methods. Median acute pulmonary exacerbation rate and time period until the first exacerbation were similar in both groups (p = .821, p = .092, respectively). Comfort and effectiveness of OPEPT was higher than CCP according to patients (p = .029 and p = .042, respectively). There were no adverse effects with either therapy. OPEPT was as effective as CCP in PCD patients. OPEPT was more comfortable and effective than CCP according to patients. OPEPT might be an efficient alternative method for airway cleareance in PCD patients.

Super-Resolution Microscopy and FIB-SEM Imaging Reveal Parental Centriole-Derived, Hybrid Cilium in Mammalian Multiciliated Cells.

Motile cilia are cellular beating machines that play a critical role in mucociliary clearance, cerebrospinal fluid movement, and fertility. In the airways, hundreds of motile cilia present on the surface of a multiciliated epithelia cell beat coordinately to protect the epithelium from bacteria, viruses, and harmful particulates. During multiciliated cell differentiation, motile cilia are templated from basal bodies, each extending a basal foot-an appendage linking motile cilia together to ensure coordinated beating. Here, we demonstrate that among the many motile cilia of a multiciliated cell, a hybrid cilium with structural features of both primary and motile cilia is harbored. The hybrid cilium is conserved in mammalian multiciliated cells, originates from parental centrioles, and its cellular position is biased and dependent on ciliary beating. Furthermore, we show that the hybrid cilium emerges independently of other motile cilia and functions in regulating basal body alignment.

Generation of two hiPSC clones (MHHi019-A, MHHi019-B) from a primary ciliary dyskinesia patient carrying a homozygous deletion in the NME5 gene (c.415delA (p.Ile139Tyrfs*8)).

Primary ciliary dyskinesia (PCD) is a genetic disorder characterized by defects in motile cilia and is known to occur in about 1 in 20,000 live births (Horani and Ferkol, 2018). Among the many genes associated with PCD, NME5, a gene encoding a protein involved in ciliary function, was recently reported to be involved in PCD (Anderegg et al., 2019; Cho et al., 2020). We have established two human induced pluripotent stem cell clones from a PCD patient carrying a deletion in the NME5 gene (c.415delA (p.Ile139Tyrfs*8)).

Mutation of CFAP57, a protein required for the asymmetric targeting of a subset of inner dynein arms in Chlamydomonas, causes primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is characterized by chronic airway disease, reduced fertility, and randomization of the left/right body axis. It is caused by defects of motile cilia and sperm flagella. We screened a cohort of affected individuals that lack an obvious axonemal defect for pathogenic variants using whole exome capture, next generation sequencing, and bioinformatic analysis assuming an autosomal recessive trait. We identified one subject with an apparently homozygous nonsense variant [(c.1762C>T), p.(Arg588*)] in the uncharacterized CFAP57 gene. Interestingly, the variant results in the skipping of exon 11 (58 amino acids), which may be due to disruption of an exonic splicing enhancer. In normal human nasal epithelial cells, CFAP57 localizes throughout the ciliary axoneme. Nasal cells from the PCD patient express a shorter, mutant version of CFAP57 and the protein is not incorporated into the axoneme. The missing 58 amino acids include portions of WD repeats that may be important for loading onto the intraflagellar transport (IFT) complexes for transport or docking onto the axoneme. A reduced beat frequency and an alteration in ciliary waveform was observed. Knockdown of CFAP57 in human tracheobronchial epithelial cells (hTECs) recapitulates these findings. Phylogenetic analysis showed that CFAP57 is highly conserved in organisms that assemble motile cilia. CFAP57 is allelic with the BOP2/IDA8/FAP57 gene identified previously in Chlamydomonas reinhardtii. Two independent, insertional fap57 Chlamydomonas mutant strains show reduced swimming velocity and altered waveforms. Tandem mass tag (TMT) mass spectroscopy shows that FAP57 is missing, and the “g” inner dyneins (DHC7 and DHC3) and the “d” inner dynein (DHC2) are reduced, but the FAP57 paralog FBB7 is increased. Together, our data identify a homozygous variant in CFAP57 that causes PCD that is likely due to a defect in the inner dynein arm assembly process.

Sinus Development and Pneumatization in a Primary Ciliary Dyskinesia Cohort.

BackgroundPrimary ciliary dyskinesia (PCD) is a genetically diverse disease which causes impaired mucociliary clearance, and results in pulmonary, otologic, and rhinologic disease in affected patients. Genetic mutations in multiple genes impair the ability of patients to clear mucous from the lungs, middle ear, and sinonasal cavity and lead to chronic pulmonary and sinonasal symptoms.MethodsWe identified 17 PCD patients who had available CT scans. Volumes for bilateral maxillary, sphenoid, and frontal sinuses were calculated. A control population of patients who had preoperative CT scans for endoscopic endonasal resection of skull base pathology without sinonasal cavity involvement was also identified.ResultsThe mean age of PCD was 33 and ranged from 13 to 54 years. Patients were age- and gender-matched to a control group that underwent resection of anterior skull-base tumors and had a mean age of 35 that ranged between 17–53 years old. The volumes for all thee sinus cavities were significantly smaller (p < 0.007) compared to the control population. The average Lund-Mackay score was 10.6 in the PCD cohort (range 6–16) in comparison to an average of 0.7 in the control cohort (range 0–2).ConclusionsOverall sinus volumes were smaller in patients with PCD compared to our control population. Future studies will be aimed at understanding defects in sinus development as a function of specific genetic mutations in PCD patients. Ultimately, a better understanding of the underlying pathophysiology of PCD will allow us to identify the optimal treatment practices for this unique patient group.

Generation of two hiPSC lines (MHHi016-A, MHHi016-B) from a primary ciliary dyskinesia patient carrying a homozygous 5bp duplication (c.248_252dup (p.Gly85Cysfs*11)) in exon 1 of the CCNO gene.

Cyclin O (CCNO) is involved in cell cycle regulation and mutations of CCNO are linked to the rare genetic disease primary ciliary dyskinesia (PCD). Mutations in CCNO are associated with reduced cilia number and cilia agenesis on epithelia of the respiratory tract. This article deals with the description of two hiPSC lines generated from a PCD patient carrying a mutation in exon 1 of the CCNO gene. The lines offer a valuable tool for in vitro modeling PCD pathophysiology.

SCO-Spondin Defects and Neuroinflammation Are Conserved Mechanisms Driving Spinal Deformity across Genetic Models of Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) affects 3% to 4% of children between the ages of 11 and 18 [1, 2]. This disorder, characterized by abnormal three-dimensional spinal curvatures that typically develop during periods of rapid growth, occurs in the absence of congenital vertebral malformations or neuromuscular defects [1]. Genetic heterogeneity [3] and a historical lack of appropriate animal models [4] have confounded basic understanding of AIS biology; thus, treatment options remain limited [5, 6]. Recently, genetic studies using zebrafish have linked idiopathic-like scoliosis to irregularities in motile cilia-mediated cerebrospinal fluid flow [7-9]. However, because loss of cilia motility in human primary ciliary dyskinesia patients is not fully associated with scoliosis [10, 11], other pathogenic mechanisms remain to be determined. Here, we demonstrate that zebrafish scospondin (sspo) mutants develop late-onset idiopathic-like spinal curvatures in the absence of obvious cilia motility defects. Sspo is a large secreted glycoprotein functionally associated with the subcommissural organ and Reissner's fiber [12]-ancient and enigmatic organs of the brain ventricular system reported to govern cerebrospinal fluid homeostasis [13, 14], neurogenesis [12, 15-18], and embryonic morphogenesis [19]. We demonstrate that irregular deposition of Sspo within brain ventricles is associated with idiopathic-like scoliosis across diverse genetic models. Furthermore, Sspo defects are sufficient to induce oxidative stress and neuroinflammatory responses implicated in AIS pathogenesis [9]. Through screening for chemical suppressors of sspo mutant phenotypes, we also identify potent agents capable of blocking severe juvenile spine deformity. Our work thus defines a new preclinical model of AIS and provides tools to realize novel therapeutic strategies.

Health related quality of life in adult primary Ciliary dyskinesia patients in Cyprus: development and validation of the Greek version of the QOL-PCD questionnaire

BackgroundThe QOL-PCD questionnaire is a recently developed Health Related Quality of Life (HRQoL) instrument for Primary Ciliary Dyskinesia. The aim of this study was to translate the adult QOL-PCD questionnaire into Greek language and to conduct psychometric validation to assess its performance.MethodsForward translations to Greek and backward translation to English were performed, followed by cognitive interviews in 12 adult PCD patients. The finalized translated version was administered to a consecutive sample of 31 adult, Greek speaking PCD patients in Cyprus for psychometric validation, which included assessment of internal consistency, test-retest reliability, construct and convergent validity. Internal consistency was assessed by Cronbach’s alpha test in terms of the overall and sub-scales. Test-retest reliability was assessed by repeat administration of the questionnaire within 2 weeks and calculation of the intra-class correlation (ICC). Construct validity was assessed by comparing different groups of patients based on a-priori hypotheses and convergent validity was evaluated by examining associations between the QOL-PCD and SF-36 questionnaires.ResultsModerate to good internal consistency was observed (Cronbach’s α: 0.46–0.88 across sub-scales) and test-retest reliability assessment demonstrated good repeatability for most scales (ICC: 0.67–0.91 across subscales). Patients of female gender, older age and lower lung function exhibited lower QOL-PCD scores in general, while high correlations for most QOL-PCD scales with corresponding SF-36 scales were observed, in particular for physical functioning (r = 0.78, p < 0.05).ConclusionThe adult version of QoL-PCD questionnaire has been translated according to international guidelines resulting to a cross-culturally validated Greek version which exhibited moderate to good metric properties in terms of internal consistency, stability, known-group and convergent validity.

Registries and collaborative studies for primary ciliary dyskinesia in Europe.

Primary ciliary dyskinesia (PCD) is a rare inherited disease characterised by malfunctioning cilia leading to a heterogeneous clinical phenotype with many organ systems affected. There is a lack of data on clinical presentation, prognosis and effectiveness of treatments, making it mandatory to improve the scientific evidence base.This article reviews the data resources that are available in Europe for clinical and epidemiological research in PCD, namely established national PCD registries and national cohort studies, plus two large collaborative efforts (the international PCD (iPCD) Cohort and the International PCD Registry), and discusses their strengths, limitations and perspectives.Denmark, Cyprus, Norway and Switzerland have national population-based registries, while England and France conduct multicentre cohort studies. Based on the data contained in these registries, the prevalence of diagnosed PCD is 3–7 per 100 000 in children and 0.2–6 per 100 000 in adults. All registries, together with other studies from Europe and beyond, contribute to the iPCD Cohort, a collaborative study including data from over 4000 PCD patients, and to the International PCD Registry, which is part of the ERN (European Reference Network)-LUNG network.This rich resource of readily available, standardised and contemporaneous data will allow obtaining fast answers to emerging clinical and research questions in PCD.