Diagnosing primary ciliary dyskinesia: an international patient perspective

'Don't let it hold you back' - The experience of transition to adulthood in young people with primary ciliary dyskinesia: An interpretative phenomenological analysis

Primary ciliary dyskinesia (PCD) is a rare, chronic genetic condition with variable features arising from motile cilia dysfunction, including recurrent respiratory infections, sinonasal disease, reduced hearing, infertility and situs inversus. The aim of the study was to understand the experiences of young people with PCD as they transition into adulthood and adult healthcare services. An interpretative phenomenological analytical method was applied. Semi-structured interviews were conducted with three participants aged 18-24 years. Four interconnected group experiential themes were identified: (1) reconceptualising a stigmatised identity, (2) sharing the journey to independence, (3) entering adulthood with newfound autonomy, (4) anticipating an uncertain future. Overall, we found that transition for young people with PCD presents as a complex period marked by identity-formation, creating systems of support and becoming an autonomous adult. Facilitation of personalised and integrated approaches to care should be prioritised. Our findings are important to help health professionals provide appropriate, anticipatory support.

Primary Ciliary Dyskinesia in Adult Bronchiectasis: Data from the German Bronchiectasis Registry PROGNOSIS

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare genetic disorder caused by the malfunction of motile cilia and a specific etiology of adult bronchiectasis of unknown prevalence. A better understanding of the clinical phenotype of adults with PCD is needed to identify individuals for referral to diagnostic testing.

RESEARCH QUESTION

What is the frequency of PCD among adults with bronchiectasis; how do people with PCD differ from those with other etiologies; and which clinical characteristics are independently associated with PCD?

STUDY DESIGN AND METHODS

We investigated the proportion of PCD among the participants of the German Bronchiectasis Registry PROGNOSIS, applied multiple imputation to account for missing data in 64 (FEV1), 58 (breathlessness), 26 (pulmonary exacerbations), and two patients (BMI), respectively, and identified predictive variables from baseline data using multivariate logistic regression analysis.

RESULTS

We consecutively recruited 1,000 patients from 38 centers across all levels of the German health care system. Overall, PCD was the fifth most common etiology of bronchiectasis in 87 patients (9%) after idiopathic, postinfective, COPD, and asthma. People with PCD showed a distinct clinical phenotype. In multivariate regression analysis, the chance of PCD being the etiology of bronchiectasis increased with the presence of upper airway disease (chronic rhinosinusitis and/or nasal polyps; adjusted OR [aOR], 6.3; 95% CI, 3.3-11.9; P < .001), age < 53 years (aOR, 5.3; 95% CI, 2.7-10.4; P < .001), radiologic involvement of any middle and lower lobe (aOR, 3.7; 95% CI, 1.3-10.8; P = .016), duration of bronchiectasis > 15 years (aOR, 3.6; 95% CI, 1.9-6.9; P < .001), and a history of Pseudomonas aeruginosa isolation from respiratory specimen (aOR, 2.4; 95% CI, 1.3-4.5; P = .007).

INTERPRETATION

Within our nationally representative cohort, PCD was a common etiology of bronchiectasis. We identified few easy-to-assess phenotypic features, which may promote awareness for PCD among adults with bronchiectasis.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02574143; URL: www.

CLINICALTRIALS

gov.

Role of Nasal Nitric Oxide in Primary Ciliary Dyskinesia and Other Respiratory Conditions in Children

Nitric oxide (NO) is produced within the airways and released with exhalation. Nasal NO (nNO) can be measured in a non-invasive way, with different devices and techniques according to the age and cooperation of the patients. Here, we conducted a narrative review of the literature to examine the relationship between nNO and some respiratory diseases with a particular focus on primary ciliary dyskinesia (PCD). A total of 115 papers were assessed, and 50 were eventually included in the review. nNO in PCD is low (below 77 nL/min), and its measurement has a clear diagnostic value when evaluated in a clinically suggestive phenotype. Many studies have evaluated the role of NO as a molecular mediator as well as the association between nNO values and genotype or ciliary function. As far as other respiratory diseases are concerned, nNO is low in chronic rhinosinusitis and cystic fibrosis, while increased values have been found in allergic rhinitis. Nonetheless, the role in the diagnosis and prognosis of these conditions has not been fully clarified.

Diagnostic testing in people with primary ciliary dyskinesia: An international participatory study

Diagnostic tests are important in primary ciliary dyskinesia (PCD), a rare disease, to confirm the diagnosis and characterize the disease. We compared diagnostic tests for PCD between countries worldwide, assessed whether people with PCD recall their tests, and identified factors associated with the use of tests. We used cross-sectional data from COVID-PCD-an international participatory cohort study collecting information directly from people with PCD. The baseline questionnaire inquired about tests used for PCD diagnosis. Using logistic regression, we investigated factors associated with measurement of nasal nitric oxide (nNO), biopsy for electron or video microscopy, and genetic testing. We included data from 747 participants (60% females) from 49 countries worldwide with median age 27 (interquartile range 12-44). Most (92%) reported diagnostic tests for PCD. Participants reported measurements of nNO (342; 49%), biopsy samples (561; 75%), and genetic tests (435; 58%). The reported use of individual tests, such as genetics, varied between countries from 38% in Switzerland to 68% in North America. Participant recall of test type also differed between countries with lowest recall in Switzerland. One-third (232; 36%) of participants reported all three tests (nNO, biopsy, and genetics). Recently diagnosed people reported more tests [nNO odds ratio (OR) 2.2, 95% Confidence Interval (CI) 1.5-3.2; biopsy OR 3.2, 95%CI 2.1-4.9; genetics OR 4.7, 95%CI 3.2-6.9] and those with situs abnormalities fewer tests (nNO OR 0.5, 95%CI 0.4-0.7; biopsy OR 0.5, 95%CI 0.4-0.8; genetics OR 0.7, 95%CI 0.5-0.94). Our results indicate PCD diagnostic testing differed widely around the world and many patients received incomplete diagnostic work-up based only on clinical features or single tests. People diagnosed long ago and those with situs abnormalities possibly benefit from supplementary testing to refine their diagnosis as a prerequisite for personalized medicine.

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.

Comparison of mental health in individuals with primary ciliary dyskinesia, cystic fibrosis, and parent caregivers

INTRODUCTION

Individuals with chronic respiratory diseases and caregivers are at higher risk for depression and anxiety. Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are both rare genetic diseases, characterized by recurrent respiratory infections. This study compared depression and anxiety in people with PCD (pwPCD) and CF (pwCF), and caregivers, using the screening tools recommended in the CF guidelines.

METHODS

Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder (GAD-7) were administered to a PCD and CF sample. Given that PCD is extremely rare, they were matched on age and sex to pwCF at a 1:2 ratio. Similar procedures were performed with parents.

RESULTS

A total of 63 patients and 129 caregivers participated: 21 pwPCD and 42 pwCF (ages 12-34 years) plus 43 caregivers of pwPCD and 86 caregivers of pwCF. A high percentage of patients scored above the cut-off for depression (PCD: 33%; CF: 43%) and anxiety (PCD and CF both: 43%), mostly mild. Similarly, a high percentage of caregivers scored above the cut-off for depression (PCD: 42-54%; CF: 45-46%) and anxiety (PCD: 47-54%; CF: 39-56%). Suicidal ideation was endorsed by 9.5% of pwPCD, 20% of mothers and 10% of fathers and 5% of pwCF, 3% of mothers, but no fathers.

CONCLUSION

A large percentage of patients and caregivers reported elevated psychological distress and suicidal ideation. Addressing psychological symptoms is critical given they are associated with poor adherence, missed clinic visits, increased inflammation and worse quality of life. Mental health screening and treatment should be integrated into PCD care.

Novel SPEF2 Variant in a Japanese Patient with Primary Ciliary Dyskinesia: A Case Report and Literature Review

Primary ciliary dyskinesia (PCD) is a genetic and congenital disease associated with an abnormal ciliary ultrastructure and function and is estimated to affect 1 in 15,000-20,000 individuals. A PCD diagnosis can be achieved by genotyping. Here, we performed whole-exome analysis for the diagnosis of PCD and described the detailed clinical characteristics of the case. A 39-year-old Japanese woman with sinusitis and bronchiectasis without situs inversus had had upper and lower respiratory symptoms since childhood and had received long-term macrolide therapy without an accurate diagnosis. A moderate deterioration of cilia function was observed by high-speed video microscopy analysis; additionally, the number of cells with moving cilia was fewer than that in patients without PCD. Electron microscopy revealed no apparent structural abnormalities. We performed whole-exome analysis and identified novel biallelic variants of SPEF2 in the homozygous state (c.1860_1861insCT). We confirmed the absence of SPEF2 protein expression in the cilia of the nasal mucosa using fluorescent immunostaining. Accordingly, she was diagnosed as having PCD with the SPEF2 variant. The present case suggests that the deterioration of cilia function is moderate, the number of respiratory cells with moving cilia might be reduced, and the respiratory condition could be severe in patients with PCD with the SPEF2 variant.

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.

Challenges in Diagnosing Primary Ciliary Dyskinesia in a Brazilian Tertiary Hospital

Primary ciliary dyskinesia (PCD) causes cellular cilia motility alterations, leading to clinical manifestations in the upper and lower respiratory tract and situs abnormalities. The PCD diagnosis was improved after the inclusion of diagnostic tools, such as transmission electron microscopy and genetic screening; however, the PCD screening is a challenge yet. In this context, we aimed to describe the clinical, genetic, and ultra-ciliary characteristics in individuals with clinical suspicion of PCD (cPCD) from a Brazilian Tertiary Hospital. An observational study was carried out with individuals during the follow-up between 2011 and 2021. The individuals were submitted to clinical questionnaires, transmission electron microscopy, and genetic screening for pathogenic variants in PCD-related genes. Those patients were classified according to the degree of suspicion for PCD. In our study, we enrolled thirty-seven cPCD individuals; 20/37 (54.1%) had chronic rhinosinusitis, 28/37 (75.6%) had bronchiectasis, and 29/37 (78.4%) had recurrent pneumonia. A total of 17/37 (45.9%) individuals had transmission electron microscopy or genetic confirmation of PCD; 10 individuals had at least one positive pathogenic genetic variant in the PCD-related genes; however, only seven patients presented a conclusive result according to the American College of Medical Genetics and Genomics and the Association for Molecular Pathology with two pathogenic variants in homozygous or compound heterozygous. The median age at diagnosis was 13 years, and the median time between suspicion and diagnosis was four years. Sixteen patients had class I electron microscopy alterations, seven had class II alterations, and 14 had normal transmission electron microscopy according to the international consensus guideline for reporting transmission electron microscopy results in the diagnosis of PCD (BEAT-PCD TEM Criteria). Genetic screening for pathogenic variants in PCD-related genes and transmission electron microscopy can help determine the PCD diagnosis; however, they are still unavailable to all individuals with clinical suspicion in Brazil. We described ultrastructural alterations found in our population along with the identification of pathogenic variants in PCD-related genes.

Clinical and genetic features of primary ciliary dyskinesia in a cohort of consecutive clinically suspect children in western China

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare, inherited disorder of the motile cilia that exhibits genetic and clinical heterogeneity among different populations. PCD diagnosis remains challenging owing to the heterogeneity of associated clinical features and lack of a gold standard diagnostic test.

OBJECTIVE

The aim of this study was to analyze the clinical and genetic characteristics of a group of children with clinically suspected PCD in one region of China, with the goal of providing a more robust knowledge base regarding the genetic stratification underlying this disease in Chinese populations.

METHODS

We retrospectively analyzed the data from 38 patients with clinically suspected PCD who had undergone next-generation sequencing (NGS) between November 2016 and March 2021 in the respiratory department of a tertiary Children's hospital in Western China. The genetic features of the confirmed cases were summarized by reviewing data associated with other cohorts of Chinese children.

RESULTS

Overall, 16 patients were ultimately diagnosed with PCD with a median age of 8.5 years. All patients presented with a chronic wet cough, 93.75% exhibited chronic or recurrent sinusitis/rhinitis, 43.75% experienced recurrent wheezing, 56.25% reported respiratory symptoms present since infancy, 31.25% had a history of neonatal respiratory distress (NRD), and 25% exhibited otitis media. Only 18.75% of these patients exhibited laterality defects. High frequencies of DNAH11 mutations were detected by integrating data from PCD patient cohorts in China.

CONCLUSION

The high frequency of DNAH11 mutations may limit the utility of transmission electron microscopy (TEM) as a first-line approach to diagnosing PCD in China in the absence of other indicators.

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.

Feasibility of nasal NO screening in healthy newborns

BACKGROUND

Nasal nitric oxide (nNO) measurement is recommended as a first line screening test for primary ciliary dyskinesia (PCD). While reliable velum- and non-velum-closure techniques exist for preschool children and older individuals, no data are available for neonates.

AIMS

To determine feasibility of nNO screening and nNO concentration in healthy newborns in the first week of life.

METHODS

Nasal NO was analyzed in tidal breathing during natural sleep using a CLD-88 sp NO analyzer (chemoluminescence sensor) and a NIOX MINO (electrochemical sensor). Test success and nNO concentration were determined and compared between the two devices.

RESULTS

Nasal NO was measured in 62 healthy neonates within the first week of life. Feasibility of nNO measurement was 100% for at least one nostril and 85.5% for both nostrils using the chemoluminescence device, but significantly lower with the electrochemical device (85.5% and 53.2%; p < .001). Median nNO concentration was 38 ppb (interquartile range, 27-55; range, 9-100) with the ECOMEDICS device and 23 (15-33, 8-59) with the NIOX MINO (p < .001), with a trend towards higher values for older subjects. None of the subjects exceeded nNO levels of 100 ppb.

CONCLUSION

Measurement of nNO using a chemoluminescence device is highly feasible in newborns during natural sleep. However, nNO levels are considerably lower compared to the published data for older individuals and in the range of a PCD reference group of infants between 4 and 8 weeks of age, potentially resulting in a great overlap with subjects with PCD in this age group. Therefore, screening for PCD using nasal NO might not be useful in the first week of life. Upon clinical suspicion, other diagnostic tests such as high-speed video analysis of the cilia should be applied.

Diagnosis of primary ciliary dyskinesia: discrepancy according to different algorithms

Background

Diagnosis of primary ciliary dyskinesia (PCD) is challenging since there is no gold standard test. The European Respiratory (ERS) and American Thoracic (ATS) Societies developed evidence-based diagnostic guidelines with considerable differences.

Objective

We aimed to compare the algorithms published by the ERS and the ATS with each other and with our own PCD-UNIBE algorithm in a clinical setting. Our algorithm is similar to the ERS algorithm with additional immunofluorescence staining. Agreement (Cohen's κ) and concordance between the three algorithms were assessed in patients with suspicion of PCD referred to our diagnostic centre.

Results

In 46 out of 54 patients (85%) the final diagnosis was concordant between all three algorithms (30 PCD negative, 16 PCD positive). In eight patients (15%) PCD diagnosis differed between the algorithms. Five patients (9%) were diagnosed as PCD only by the ATS, one (2%) only by the ERS and PCD-UNIBE, one (2%) only by the ATS and PCD-UNIBE, and one (2%) only by the PCD-UNIBE algorithm. Agreement was substantial between the ERS and the ATS (κ=0.72, 95% CI 0.53–0.92) and the ATS and the PCD-UNIBE (κ=0.73, 95% CI 0.53–0.92) and almost perfect between the ERS and the PCD-UNIBE algorithms (κ=0.92, 95% CI 0.80–1.00).

Conclusion

The different diagnostic algorithms lead to a contradictory diagnosis in a considerable proportion of patients. Thus, an updated, internationally harmonised and standardised PCD diagnostic algorithm is needed to improve diagnostics for these discordant cases.

There is no gold standard test for diagnosing PCD. The use of existing diagnostic algorithms leads to contradicting results in many patients (15% in this study). Thus, an updated and internationally harmonised diagnostic guideline is needed.https://bit.ly/2U19Vvq

Anxiety and depression in Dutch patients with primary ciliary dyskinesia and their caregivers: associations with health-related quality of life

Background

Primary ciliary dyskinesia (PCD) might be a risk factor for the development of anxiety and depression. This study investigated the associations between anxiety, depression and health-related quality of life (HRQoL) in individuals with PCD and their caregivers.

Methods

Children, adolescents and adults with PCD and their caregivers were invited to participate in a mental health screening programme. During regular yearly outpatient visits, measures of anxiety (GAD-7), depression (PHQ-9), HRQoL (QOL-PCD), lung function (forced expiratory volume in 1 s (FEV₁)) and body mass index (BMI)) were collected and associations of anxiety, depression and HRQoL were estimated.

Results

A total of 103 individuals participated in the mental health screening programme. Elevated levels of anxiety (scores ≥10 on GAD-7) were found in 6% of adults (n=33), 14% of children (n=7), 6% of adolescents (n=17) and 20% of caregivers (n=46, 52% of mothers). Elevated depression levels (scores ≥10 on PHQ-9) were found in 18% of adults, 14% of children, 6% of adolescents and 11% of caregivers. Anxiety and depression were associated with scales on the QOL-PCD. Mothers reported higher anxiety scores than fathers (30% versus 9%, p=0.03). A strong negative relationship was found between depression in caregivers and physical functioning (QOL-PCD) of the child. Anxiety and depression were not significantly associated with anxiety/depression in their child.

Conclusion

This is the first study investigating anxiety and depression in individuals with PCD and their caregivers. Our results revealed elevated levels of anxiety and depression, which were associated with worse HRQoL. These results suggest the need for psychological support in PCD.

Individuals with PCD and their caregivers are at risk of developing symptoms of anxiety and depression, which are associated with worse HRQoL. There is an urgent need for psychological care in PCD, especially in adults with PCD and caregivers.https://bit.ly/3rmbgc9

Whole genome sequencing in the diagnosis of primary ciliary dyskinesia

BACKGROUND

It is estimated that 1-13% of cases of bronchiectasis in adults globally are attributable to primary ciliary dyskinesia (PCD) but many adult patients with bronchiectasis have not been investigated for PCD. PCD is a disorder caused by mutations in genes required for motile cilium structure or function, resulting in impaired mucociliary clearance. Symptoms appear in infancy but diagnosis is often late or missed, often due to the lack of a "gold standard" diagnostic tool and non-specific symptoms. Mutations in > 50 genes account for around 70% of cases, with additional genes, and non-coding, synonymous, missense changes or structural variants (SVs) in known genes presumed to account for the missing heritability.

METHODS

UK patients with no identified genetic confirmation for the cause of their PCD or bronchiectasis were eligible for whole genome sequencing (WGS) in the Genomics England Ltd 100,000 Genomes Project. 21 PCD probands and 52 non-cystic fibrosis (CF) bronchiectasis probands were recruited in Wessex Genome Medicine Centre (GMC). We carried out analysis of single nucleotide variants (SNVs) and SVs in all families recruited in Wessex GMC.

RESULTS

16/21 probands in the PCD cohort received confirmed (n = 9), probable (n = 4) or possible (n = 3) diagnosis from WGS, although 13/16 of these could have been picked up by current standard of care gene panel testing. In the other cases, SVs were identified which were missed by panel testing. We identified variants in novel PCD candidate genes (IFT140 and PLK4) in 2 probands in the PCD cohort. 3/52 probands in the non-CF bronchiectasis cohort received a confirmed (n = 2) or possible (n = 1) diagnosis of PCD. We identified variants in novel PCD candidate genes (CFAP53 and CEP164) in 2 further probands in the non-CF bronchiectasis cohort.

CONCLUSIONS

Genetic testing is an important component of diagnosing PCD, especially in cases of atypical disease history. WGS is effective in cases where prior gene panel testing has found no variants or only heterozygous variants. In these cases it may detect SVs and is a powerful tool for novel gene discovery.

Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is an inherited cause of bronchiectasis. The estimated PCD prevalence in children with bronchiectasis is up to 26% and in adults with bronchiectasis is 1 to 13%. Due to dysfunction of the multiple motile cilia of the respiratory tract patients suffer from poor mucociliary clearance. Clinical manifestations are heterogeneous; however, a typical patient presents with chronic productive cough and rhinosinusitis from early life. Other symptoms reflect the multiple roles of motile cilia in other organs and can include otitis media and hearing loss, infertility, situs inversus, complex congenital heart disease, and more rarely other syndromic features such as hydrocephalus and retinitis pigmentosa. Awareness, identification, and diagnosis of a patient with PCD are important for multidisciplinary care and genetic counseling. Diagnosis can be pursued through a multitest pathway which includes the measurement of nasal nitric oxide, sampling the nasal epithelium to assess ciliary function and structure, and genotyping. Diagnosis is confirmed by the identification of a hallmark ultrastructural defect or pathogenic mutations in one of > 45 PCD causing genes. When a diagnosis is established management is centered around improving mucociliary clearance through physiotherapy and treatment of infection with antibiotics. The first international randomized controlled trial in PCD has recently been conducted showing azithromycin is effective in reducing exacerbations. It is likely that evidence-based PCD-specific management guidelines and therapies will be developed in the near future. This article examines prevalence, clinical features, diagnosis, and management of PCD highlighting recent advances in basic science and clinical care.

A quantitative super-resolution imaging toolbox for diagnosis of motile ciliopathies

Airway clearance of pathogens and particulates relies on motile cilia. Impaired cilia motility can lead to reduction in lung function, lung transplant, or death in some cases. More than 50 proteins regulating cilia motility are linked to primary ciliary dyskinesia (PCD), a heterogeneous, mainly recessive genetic lung disease. Accurate PCD molecular diagnosis is essential for identifying therapeutic targets and for initiating therapies that can stabilize lung function, thereby reducing socioeconomic impact of the disease. To date, PCD diagnosis has mainly relied on nonquantitative methods that have limited sensitivity or require a priori knowledge of the genes involved. Here, we developed a quantitative super-resolution microscopy workflow: (i) to increase sensitivity and throughput, (ii) to detect structural defects in PCD patients' cells, and (iii) to quantify motility defects caused by yet to be found PCD genes. Toward these goals, we built a localization map of PCD proteins by three-dimensional structured illumination microscopy and implemented quantitative image analysis and machine learning to detect protein mislocalization, we analyzed axonemal structure by stochastic optical reconstruction microscopy, and we developed a high-throughput method for detecting motile cilia uncoordination by rotational polarity. Together, our data show that super-resolution methods are powerful tools for improving diagnosis of motile ciliopathies.

Emotional experience of the diagnostic process of a rare disease and the perception of support systems: A scoping review

AIMS AND OBJECTIVE

To explore the experience of adult patients and adult patients' families, and their perception of the support systems received during the diagnostic process of rare diseases.

BACKGROUND

There are about 7,000 rare diseases that affect 7% of the world's population. Rare diseases are often underdiagnosed. This has been reported to have deleterious physical and psychological consequences in both the patients and their families, especially when institutional support during this process is low.

DESIGN

A scoping review was carried out following the 6-phase model proposed by Arksey & O'Malley and Levac et al., including the consultation phase in which patients diagnosed with rare diseases were interviewed to seek their views on the bibliographic evidence reviewed and their experience during the diagnostic process.

METHODS

The databases consulted were PubMed, CINAHL, Web of Science, SCOPUS, Cochrane Library, PsycINFO, OpenGrey, ProQuest Dissertations and Theses Global. They were explored from inception-July 2020, and qualitative, quantitative and mixed method studies were included. The Mixed Methods Appraisal Tool was used for the critical evaluation of the articles. The review was based on the guidance in the PRISMA-ScR statement.

RESULTS

The initial search identified 2,350 articles, of which 20 fully met the inclusion criteria and were therefore reviewed. In this analysis appeared two dimensions: internal factors: emotional aspects, and external factors: resources and support systems.

RELEVANCE TO CLINICAL

This review provides evidence on the emotional impact of the diagnostic process and during the communication phase of the definitive diagnosis. Health systems and professionals must be strengthened in order to improve the information, training and resources. Nurses can play a key role in coordinating communication and follow-up of those affected.

Access to medicines for rare diseases: beating the drum for primary ciliary dyskinesia

Rare diseases are collectively common, affecting an estimated 6.2% of the world's population [1], but each rare disease affects fewer than 4 to 5 in 10 000 individuals in Europe or less than 200 000 individuals in the USA [2]. Patients with rare diseases are often disadvantaged by late diagnosis and off-label prescribing of medicines [3]. Primary ciliary dyskinesia (PCD) is a genetic disease of impaired motile ciliary function that does not have a unique International Classification of Diseases (ICD)-10 code or licensed treatments, although Q34.8 denoting “other specified malformations of the respiratory tract” including nasopharyngeal atresia has also been applicable to PCD since 2017. The disease is characterised by mucus stagnation leading to chronic airway infection, bronchiectasis, chronic rhinosinusitis, reduced fertility and abnormalities of organ laterality with an associated increased risk of complex congenital heart disease [4]. The estimated prevalence of PCD in Europe is around 1 in 10 000 to 1 in 20 000 [5]. The international PCD cohort (iPCD) includes over 3800 PCD patients ranging in age from under 12 months to over 80 years, from Europe, Northern and Southern America, Australia and Western Asia [6]. Under-diagnosis of PCD is due to a lack of awareness among the general public and physicians in general, as well as a lack of diagnostic expertise in some countries [7]. Tools to help physicians identify patients needing testing (e.g. PICADAR) [8] and the European Respiratory Society (ERS) guidelines for diagnostic testing [9] aim to improve this. In contrast to cystic fibrosis (CF), a monogenic disease, PCD is caused by mutations in one of at least 45 identified genes for which there is no effective mutation-specific therapy; this is likely to be a long way off for most patients [10]. Thus, treatment aims to prevent and manage disease complications. Even then, the lack of an evidence base for supportive treatment in PCD means that treatment recommendations are based on expert opinion and extrapolated from CF despite differing pathophysiology [11].

Primary ciliary dyskinesia, a rare disease causing bronchiectasis, lacks a sound evidence base for treatment. @beatpcd proposes 1) forming a PCD European clinical trial network to address this situation and 2) conducting n-of-1 trials to access medication.https://bit.ly/3j5blfM

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.

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.

The growing collaborative network of national and international registries and cohort studies of patients with PCD provides an excellent resource for research on this rare diseasehttps://bit.ly/3dto75l

Evaluation of the pulmonary radioaerosol mucociliary clearance scan as an adjunctive test for the diagnosis of primary ciliary dyskinesia in children

INTRODUCTION

The accuracy of primary ciliary dyskinesia (PCD) diagnosis has improved but no single test is diagnostic and some cases remain unsolved. Data regarding the accuracy of pulmonary radioaerosol mucociliary clearance scan (PRMCC) for the diagnosis of PCD are limited to predominantly adults using a 24-hour test. This study was performed to determine the accuracy of a 60-minute PRMCC test for diagnosing PCD in children.

METHODS

Children with suspected PCD and inconclusive clinical diagnostic testing in an expert center were selected for PRMCC testing. Nebulized ^99m Tc sulfur colloid was inhaled and dynamic imaging acquired for 60 to 120 minutes. Two independent radiologists blinded to the clinical diagnosis and health records overread PRMCC studies. The PRMCC result was compared with the reference standard diagnosis of PCD made by two physicians using the cumulative health record, blinded to PRMCC results.

RESULTS

From 2008 to 2018, 57 patients (6-17 years) participated, of which 16 met criteria for the reference diagnosis of PCD. The PRMCC test was conclusive in 54 patients (94.7%) and had a sensitivity of 100% (95% confidence interval [CI] = 78.2-100), specificity of 85.7% (95% CI = 69.7-95.2), positive predictive value of 75% (95% CI = 57.1-87.1), negative predictive value of 100% (95% CI = 90.2-100), and accuracy of 90% (95% CI = 78.2-96.7).

CONCLUSION

The 60-minute PRMCC test is noninvasive and feasible in children with a high negative predictive value for PCD. It may be a helpful adjunctive test to rule out PCD when clinical suspicion remains after guideline recommended first-line clinical testing.

Validation of pediatric health-related quality of life instruments for primary ciliary dyskinesia (QOL-PCD)

RATIONALE

Having developed the first disease-specific, health-related quality of life (HRQoL) instruments for children with primary ciliary dyskinesia (PCD), we aimed to assess the psychometric performance of quality of life (QOL)-PCD child, adolescent, and parent-proxy versions in terms of reliability and validity across cross-cultural settings and caring for patients with this rare disease.

METHODS

Children (n = 71), adolescents (n = 85), and parents (n = 68) from multiple centers in the UK and North America completed age-appropriate QOL-PCD and generic QOL measures: pediatric QOL inventory, COPD assessment test (CAT), and Sino-Nasal Outcome Test 20. Total of 13 children, 13 parents, and 17 adolescents repeated QOL-PCD 10 to 14 days later to assess test-retest reliability. Multitrait analysis evaluated how the items loaded to hypothesized scales: physical, emotional & social functioning, treatment burden, role, vitality, upper and lower respiratory symptoms, and ears and hearing symptoms. Examination of item-to-total correlations led to removal of three, five, and six items, respectively in the prototype child, adolescent and parent-proxy versions; the validated measures now comprise between 34 and 38 items.

RESULTS

The QOL-PCD scales had good internal consistency; Cronbach's α for QOL-PCD parent-proxy ranged 0.62 to 0.86. Test-retest reliability demonstrated stability across all scales; for example QOL-PCD adolescent intraclass correlation coefficients ranged 0.71 to 0.89. Significant relationships were found between QOL-PCD scales and similar constructs on generic questionnaires, for example, QOL-PCD adolescent lower respiratory symptoms and the CAT score (r = .64, P < .01); weaker correlations were found between different constructs.

CONCLUSION

Age-specific QOL-PCD demonstrated good internal consistency, test-retest reliability, and validity. QOL-PCD offers promising outcome measures for multicenter clinical trials, as well as monitoring symptoms, functioning, and QOL during routine care.

Primary ciliary dyskinesia in the genomics age

Primary ciliary dyskinesia is a genetically and clinically heterogeneous syndrome. Impaired function of motile cilia causes failure of mucociliary clearance. Patients typically present with neonatal respiratory distress of unknown cause and then continue to have a daily wet cough, recurrent chest infections, perennial rhinosinusitis, otitis media with effusion, and bronchiectasis. Approximately 50% of patients have situs inversus, and infertility is common. While understanding of the underlying genetics and disease mechanisms have substantially advanced in recent years, there remains a paucity of evidence for treatment. Next-generation sequencing has increased gene discovery, and mutations in more than 40 genes have been reported to cause primary ciliary dyskinesia, with many other genes likely to be discovered. Increased knowledge of cilia genes is challenging perceptions of the clinical phenotype, as some genes reported in the last 5 years are associated with mild respiratory disease. Developments in genomics and molecular medicine are rapidly improving diagnosis, and a genetic cause can be identified in approximately 70% of patients known to have primary ciliary dyskinesia. Groups are now investigating novel and personalised treatments, although gene therapies are unlikely to be available in the near future.

Cost-effectiveness analysis of three algorithms for diagnosing primary ciliary dyskinesia: a simulation study

Background

Primary Ciliary Dyskinesia (PCD) diagnosis relies on a combination of tests which may include (a) nasal Nitric Oxide (nNO), (b) High Speed Video Microscopy (HSVM) and (c) Transmission Electron Microscopy (TEM). There is variability in the availability of these tests and lack of universal agreement whether diagnostic tests should be performed in sequence or in parallel. We assessed three combinations of tests for PCD diagnosis and estimated net sensitivity and specificity as well as cost-effectiveness (CE) and incremental cost-effectiveness (ICE) ratios.

Methods and results

A hypothetical initial population of 1000 referrals (expected 320 PCD patients) was followed through a probabilistic decision analysis model which was created to assess the CE of three diagnostic algorithms (a) nNO + TEM in sequence, (b) nNO + HSVM in sequence and (c) nNO/HSVM in parallel followed, in cases with conflicting results, by confirmatory TEM (nNO/HSVM+TEM). Number of PCD patients identified, CE and ICE ratios were calculated using Monte Carlo simulations. Out of 320 expected PCD patients, 313 were identified by nNO/HSVM+TEM, 274 with nNO + HSVM and 198 with nNO + TEM. The nNO/HSVM+TEM had the highest mean annual cost (€209 K) followed by nNO + TEM (€150 K) and nNO + HSVM (€136 K). The nNO + HSVM algorithm dominated the nNO + TEM algorithm (less costly and more effective). The ICE ratio for nNO/HSVM+TEM was €2.1 K per additional PCD patient identified.

Conclusions

The diagnostic algorithm (nNO/HSVM+TEM) with parallel testing outperforms algorithms with tests in sequence. These findings, can inform the dialogue on the development of evidence-based guidelines for PCD diagnostic testing. Future research in understudied aspects of the disease, such as PCD-related quality of life and PCD-associated costs, is needed to help the better implementation of these guidelines across various healthcare systems.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1116-3) contains supplementary material, which is available to authorized users.

Proof of Concept: Very Rapid Tidal Breathing Nasal Nitric Oxide Sampling Discriminates Primary Ciliary Dyskinesia from Healthy Subjects

INTRODUCTION

Nasal nitric oxide (nNO) is extremely low in individuals with primary ciliary dyskinesia (PCD) and is recommended as part of early workup. We investigated whether tidal breathing sampling for a few seconds was as discriminative between PCD and healthy controls (HC) as conventional tidal breathing sampling (cTB-nNO) for 20-30 s.

METHODS

We performed very rapid sampling of tidal breathing (vrTB-nNO) for 2, 4 and 6 s, respectively. Vacuum sampling with applied negative pressure (vrTB-nNO_vac; negative pressure was applied by pinching the sampling tube) for < 2 s resulted in enhanced suction of nasal air during measurement. Feasibility, success rate, discriminatory capacity, repeatability and agreement were assessed for all four sampling modalities.

RESULTS

We included 13 patients with PCD, median (IQR) age of 21.8 (12.2-27.7) years and 17 HC, 25.3 (14.5-33.4) years. Measurements were highly feasible (96.7% success rate). Measured NO values with vrTB-nNO modalities differed significantly from TB-nNO measurements (HC: p < 0.001, PCD: p < 0.05). All modalities showed excellent discrimination. The vacuum method gave remarkably high values of nNO in both groups (1865 vs. 86 ppb), but retained excellent discrimination. vrTB-nNO_4sec, vrTB-nNO_6sec and vrTB-nNO_vac showed identical specificity to cTB-nNO (all: 1.0, 95% CI 0.77-1.0).

CONCLUSION

vrTB-nNO sampling requires only a few seconds of probe-in-nose time, is feasible, and provides excellent discrimination between PCD and HC. Rapid TB-nNO sampling needs standardisation and further investigations in infants, young children and patients referred for PCD workup.

Pulmonary exacerbations in patients with primary ciliary dyskinesia: an expert consensus definition for use in clinical trials

Pulmonary exacerbations are a cause of significant morbidity in patients with primary ciliary dyskinesia (PCD) and are frequently used as an outcome measure in clinical research into chronic lung diseases. So far, there has been no consensus on the definition of pulmonary exacerbations in PCD.

30 multidisciplinary experts and patients developed a consensus definition for children and adults with PCD. Following a systematic review, the panel used a modified Delphi process with a combination of face-to-face meetings and e-surveys to develop a definition that can be used in research settings for children and adults with PCD.

A pulmonary exacerbation was defined by the presence of three or more of the following seven items: 1) increased cough, 2) change in sputum volume and/or colour, 3) increased shortness of breath perceived by the patient or parent, 4) decision to start or change antibiotic treatment because of perceived pulmonary symptoms, 5) malaise, tiredness, fatigue or lethargy, 6) new or increased haemoptysis, and 7) temperature >38°C.

The consensus panel proposed that the definition should be used for future clinical trials. The definition should be validated and the usability assessed during these studies.

A consensus definition for pulmonary exacerbations in children and adults with PCD for use in clinical trialshttp://ow.ly/Rcfr30n4Gn4

Lung function in patients with primary ciliary dyskinesia: an iPCD Cohort study

Primary ciliary dyskinesia (PCD) has been considered a relatively mild disease, especially compared to cystic fibrosis (CF), but studies on lung function in PCD patients have been few and small.This study compared lung function from spirometry of PCD patients to normal reference values and to published data from CF patients. We calculated z-scores and % predicted values for forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) using the Global Lung Function Initiative 2012 values for 991 patients from the international PCD Cohort. We then assessed associations with age, sex, country, diagnostic certainty, organ laterality, body mass index and age at diagnosis in linear regression models. Lung function in PCD patients was reduced compared to reference values in both sexes and all age groups. Children aged 6-9 years had the smallest impairment (FEV₁ z-score -0.84 (-1.03 to -0.65), FVC z-score -0.31 (-0.51 to -0.11)). Compared to CF patients, FEV₁ was similarly reduced in children (age 6-9 years PCD 91% (88-93%); CF 90% (88-91%)), but less impaired in young adults (age 18-21 years PCD 79% (76-82%); CF 66% (65-68%)). The results suggest that PCD affects lung function from early in life, which emphasises the importance of early standardised care for all patients.

Diagnostic yield of a targeted gene panel in primary ciliary dyskinesia patients

We aimed to determine the diagnostic yield of a targeted-exome panel in a cohort of 74 Dutch primary ciliary dyskinesia (PCD) patients. The panel consisted of 26 PCD-related and 284 candidate genes. To prioritize PCD candidate genes, we investigated the transcriptome of human airway cells of 12 healthy volunteers during in vitro ciliogenesis and hypothesized that PCD-related genes show significant upregulation. We compared gene expression in epithelial precursor cells grown as collagen monolayer and ciliated cells grown in suspension by RNA sequencing. All genes reported as PCD causative, except NME8, showed significant upregulation during in vitro ciliogenesis. We observed 67.6% diagnostic yield when testing the targeted-exome panel in our cohort. There was relatively high percentage of DNAI and HYDIN mutations compared to other countries. The latter may be due to our solution for the problem of the confounding HYDIN2 pseudogene. Candidate genes included two recently published PCD-related genes DNAJB13 and PIH1D3; identification of the latter was a direct result of this study. In conclusion, we demonstrate 67.6% diagnostic yield by targeted exome sequencing in a Dutch PCD population and present a highly sensitive and moderately specific approach for identification of PCD-related genes, based on significant upregulation during in vitro ciliogenesis.

Diagnosis and management of children with primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a rare, genetic disorder of the motile cilia characterised by chronic lung disease, nasal and sinus disease, chronic ear infections with glue ear leading to possible hearing impairment, and subfertility. Half of patients have organ laterality defects. Despite symptoms being present from birth, PCD remains underdiagnosed. Early diagnosis and symptom management may reduce morbidity, improve quality of life and ensure children are adequately supported to meet their full potential. This article seeks to raise awareness of PCD in children's nurses who are well placed to identify children for referral to the national PCD diagnostic service. It examines the clinical characteristics of the disease along with the complexities and limitations of diagnostic testing. In addition, it explores the management of children with PCD within the national PCD management service for children.

Clinical care for primary ciliary dyskinesia: current challenges and future directions

Primary ciliary dyskinesia (PCD) is a rare genetic disease that affects the motility of cilia, leading to impaired mucociliary clearance. It is estimated that the vast majority of patients with PCD have not been diagnosed as such, providing a major obstacle to delivering appropriate care. Challenges in diagnosing PCD include lack of disease-specific symptoms and absence of a single, “gold standard”, diagnostic test. Management of patients is currently not based on high-level evidence because research findings are mostly derived from small observational studies with limited follow-up period. In this review, we provide a critical overview of the available literature on clinical care for PCD patients, including recent advances. We identify barriers to PCD research and make suggestions for overcoming challenges.

Challenges in PCD must be overcome through international collaboration; networks must build on recent advanceshttp://ow.ly/4d4I30dXzWg

Diagnosis of primary ciliary dyskinesia: summary of the ERS Task Force report

Key points

Primary ciliary dyskinesia (PCD) is a genetically and clinically heterogeneous disease characterised by abnormal motile ciliary function.

There is no “gold standard” diagnostic test for PCD.

The European Respiratory Society (ERS) Task Force Guidelines for diagnosing PCD recommend that patients should be referred for diagnostic testing if they have several of the following features: persistent wet cough; situs anomalies; congenital cardiac defects; persistent rhinitis; chronic middle ear disease with or without hearing loss; or a history, in term infants, of neonatal upper and lower respiratory symptoms or neonatal intensive care admission.

The ERS Task Force recommends that patients should be investigated in a specialist PCD centre with access to a range of complementary tests: nasal nitric oxide, high-speed video microscopy analysis and transmission electron microscopy. Additional tests including immunofluorescence labelling of ciliary proteins and genetic testing may also help determine the diagnosis.

Educational aims

This article is intended for primary and secondary care physicians interested in primary ciliary dyskinesia (PCD), i.e. those who identify patients for testing, and those involved in diagnosing and managing PCD patients. It aims:

to inform readers about the new European Respiratory Society Task Force Guidelines for diagnosing patients with PCD

to enable primary and secondary care physicians to: identify patients who need diagnostic testing; understand the diagnostic tests that their patients will undergo, the results of the tests and their limitations; and ensure that appropriate care is subsequently delivered.

What primary and secondary care physicians should know about the diagnosis of primary ciliary dyskinesiahttp://ow.ly/obix30drts1

Diagnosis of rare diseases under focus: impacts for Canadian patients

This paper presents an in-depth qualitative analysis of the impact of diagnosis on the lives of rare disease (RD) patients. While diagnosis may be described as a watershed step for RD patients, no extensive account of non-medical outcomes following a RD diagnosis exists within the literature. This study aims to fill this knowledge gap through an analysis of the impact of diagnosis on the lives of RD patients according to their personal experiences. Qualitative research was conducted in three provinces across Canada, with a total of 23 participants, both adult and parents of children with RD, diagnosed and not yet diagnosed. A thematic approach guided the analysis of the transcripts. The results reveal that the impacts of a RD diagnosis for both adults and paediatric patients are multifold, ranging from social to personal and medical impacts (including cases where etiological treatments for the diseases are non-existent). Furthermore, the results shed light on distinct factors that affect the scope of impacts of a diagnosis.

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

Primary ciliary dyskinesia (PCD) is an orphan disease (MIM 244400), autosomal recessive inherited, characterized by motile ciliary dysfunction. The estimated prevalence of PCD is 1:10,000 to 1:20,000 live-born children, but true prevalence could be even higher. PCD is characterized by chronic upper and lower respiratory tract disease, infertility/ectopic pregnancy, and situs anomalies, that occur in ≈50% of PCD patients (Kartagener syndrome), and these may be associated with congenital heart abnormalities. Most patients report a daily year-round wet cough or nose congestion starting in the first year of life. Daily wet cough, associated with recurrent infections exacerbations, results in the development of chronic suppurative lung disease, with localized-to-diffuse bronchiectasis. No diagnostic test is perfect for confirming PCD. Diagnosis can be challenging and relies on a combination of clinical data, nasal nitric oxide levels plus cilia ultrastructure and function analysis. Adjunctive tests include genetic analysis and repeated tests in ciliary culture specimens. There are currently 33 known genes associated with PCD and correlations between genotype and ultrastructural defects have been increasingly demonstrated. Comprehensive genetic testing may hopefully screen young infants before symptoms occur, thus improving survival. Recent surprising advances in PCD genetic designed a novel approach called "gene editing" to restore gene function and normalize ciliary motility, opening up new avenues for treating PCD. Currently, there are no data from randomized clinical trials to support any specific treatment, thus, management strategies are usually extrapolated from cystic fibrosis. The goal of treatment is to prevent exacerbations, slowing the progression of lung disease. The therapeutic mainstay includes airway clearance maneuvers mainly with nebulized hypertonic saline and chest physiotherapy, and prompt and aggressive administration of antibiotics. Standardized care at specialized centers using a multidisciplinary approach that imposes surveillance of lung function and of airway biofilm composition likely improves patients' outcome. Pediatricians, neonatologists, pulmonologists, and ENT surgeons should maintain high awareness of PCD and refer patients to the specialized center before sustained irreversible lung damage develops. The recent creation of a network of PCD clinical centers, focusing on improving diagnosis and treatment, will hopefully help to improve care and knowledge of PCD patients.

The patient's experience of primary ciliary dyskinesia: a systematic review

Background

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by progressive sinopulmonary disease, with symptoms starting soon after birth. The aim of this study is to critically review, analyse, and synthesise the literature in order to understand the experiences of patients with primary ciliary dyskinesia (PCD) and the impact on health-related quality of life.

Method

MEDLINE, EBSCO, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO and EMBASE were searched according to the inclusion criteria. A qualitative analysis of 14 studies was conducted.

Results

Fourteen studies were included in the review, five with qualitative methodologies. Studies originated from the UK, USA, Italy, Denmark and Belgium, one study included a survey distributed internationally. Significant relationships were found between age and worsening of respiratory symptoms, physical, and mental domains of health-related quality of life, with a greater decline compared with reference populations. Variations between the UK and Italy were found for health-related quality of life and its correlation with time since diagnosis. PCD was found to have a physical impact in all age groups: patients found it difficult to keep up with others, and found energy levels were easily depleted compared to family or peers. In terms of social impact, symptoms lead to embarrassment and a sense of isolation, with patients concealing symptoms and/or their diagnosis. In turn, isolation was also linked with the lack of public and medical knowledge. In relation to emotional impact, anxiety was reported in a number of qualitative studies; patients were anxious about getting sick or when thinking about their future health. The burden of treatment and factors influencing adherence were also discussed in depth.

Conclusion

Health-related quality of life decreases with age in patients with PCD. For all age groups, PCD was found to greatly impact physical, emotional, social functioning, and treatment burden. More research is needed on the psychosocial impact of the illness, disease burden and its effect on quality of life.

European Respiratory Society guidelines for the diagnosis of primary ciliary dyskinesia

The diagnosis of primary ciliary dyskinesia is often confirmed with standard, albeit complex and expensive, tests. In many cases, however, the diagnosis remains difficult despite the array of sophisticated diagnostic tests. There is no "gold standard" reference test. Hence, a Task Force supported by the European Respiratory Society has developed this guideline to provide evidence-based recommendations on diagnostic testing, especially in light of new developments in such tests, and the need for robust diagnoses of patients who might enter randomised controlled trials of treatments. The guideline is based on pre-defined questions relevant for clinical care, a systematic review of the literature, and assessment of the evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach. It focuses on clinical presentation, nasal nitric oxide, analysis of ciliary beat frequency and pattern by high-speed video-microscopy analysis, transmission electron microscopy, genotyping and immunofluorescence. It then used a modified Delphi survey to develop an algorithm for the use of diagnostic tests to definitively confirm and exclude the diagnosis of primary ciliary dyskinesia; and to provide advice when the diagnosis was not conclusive. Finally, this guideline proposes a set of quality criteria for future research on the validity of diagnostic methods for primary ciliary dyskinesia.