Primary Ciliary Dyskinesia Group Research Articles

The Coronavirus Disease 2019 Pandemic and Time to Diagnosis for Childhood Pulmonary Diseases: Outcomes of a Tertiary Care Center.

Coronavirus disease 2019 pandemic caused many changes in the social behaviors of individuals and the provision of health systems. Many studies revealed reductions in the number of diagnoses and delays in diagnosis time during the pandemic. This study aimed to evaluate the effect of the pandemic on the time to diagnosis of major diseases of pediatric pulmonology. Newly diagnosed patients with cystic fibrosis (CF), childhood interstitial lung disease (chILD), tuberculosis (TB), and primary ciliary dyskinesia (PCD) were grouped into pandemic (group 1) and 2 consecutive pre-pandemic periods divided into equal intervals (groups 2 and 3). For each disease group, the time to diagnosis was compared between the specified periods. A total number of patients were 171 in this study. In the CF group, there was no statistically difference in time to diagnosis between periods. In the chILD group, there was a statistically significant difference in time to diagnosis (P = .036) between groups (group 1: 2 months, group 2: 4 months and group 3: 10.5 months) that was not originated from pandemic period. In TB group there was no statistically significant difference between groups. In the PCD group, the impact of the pandemic on the time to diagnosis could not be clarified because the time interval to diagnosis (minimum: 2 years, maximum: 16 years) exceeded the studied periods (21 months). In our study, no effect found between the pandemic and age at diagnosis or time to diagnosis in patients with PCD, chILD, CF, and TB at our center.

Quantification of Mastoid Air Cells and Opacification of the Middle Ear in Primary Ciliary Dyskinesia.

To evaluate pneumatization and opacification of the temporal bone on computed tomography (CT) images in patients with primary ciliary dyskinesia (PCD). Retrospective case-control study. Tertiary referral center. Fifteen patients with PCD (30 ears) and 45 age-matched individuals without PCD (90 ears) as controls. Diagnostic only. Quantification of mastoid air cells in the PCD and control groups and comparison between them. Degree of middle ear opacification on CT images of the temporal bone in the PCD group. The volume of the mastoid air cells was 30% smaller in the PCD group than in the control group ( p < 0.05). The suppression ratio, which is defined to indicate how much the average volume of mastoid air cells in the PCD group is suppressed relative to the control group, was 64% lower in the PCD group ( p < 0.05). Opacification was noted in 47% of the mastoid air cells and 63% of the tympanic cavity on CT images of the temporal bone in the PCD group, which were significantly higher frequencies than in the control group (1.1% and 1.1%, respectively). Compared with individuals without PCD, those with PCD showed a significantly smaller volume of mastoid air cells and a significantly higher frequency of opacification of mastoid air cells and tympanic cavity on temporal bone CT. Otitis media raises suspicion for PCD, and the otological manifestations of PCD reported here could help to narrow the differential diagnosis and facilitate early treatment.

Clinical Characteristics and Immune Responses in Children with Primary Ciliary Dyskinesia during Pneumonia Episodes: A Case-Control Study.

This study explored the clinical features and immune responses of children with primary ciliary dyskinesia (PCD) during pneumonia episodes. The 61 children with PCD who were admitted to hospital because of pneumonia were retrospectively enrolled into this study between April 2017 and August 2022. A total of 61 children with pneumonia but without chronic diseases were enrolled as the control group. The clinical characteristics, levels of inflammatory indicators, pathogens, and imaging features of the lungs were compared between the two groups. The PCD group had higher levels of lymphocytes (42.80% versus 36.00%, p = 0.029) and eosinophils (2.40% versus 1.25%, p = 0.020), but lower neutrophil counts (3.99 versus 5.75 × 109/L, p = 0.011), percentages of neutrophils (46.39% versus 54.24%, p = 0.014), CRP (0.40 versus 4.20 mg/L, p < 0.001) and fibrinogen (257.50 versus 338.00 mg/dL, p = 0.010) levels. Children with PCD and children without chronic diseases were both most commonly infected with Mycoplasma pneumoniae (24.6% versus 51.9%). Children with PCD had significantly more common imaging features, including mucous plugging (p = 0.042), emphysema (p = 0.007), bronchiectasis (p < 0.001), mosaic attenuation (p = 0.012), interstitial inflammation (p = 0.015), and sinusitis (p < 0.001). PCD is linked to immune system impairment, which significantly contributes to our understanding of the pathophysiology of this entity.

Diagnostic value of nasal nitric oxide for children with primary ciliary dyskinesia

Objective: To evaluate the value of nasal nitric oxide (nNO) measurement as a diagnostic tool for Chinese patients with primary ciliary dyskinesia (PCD). Methods: This study is a retrospective study. The patients were recruited from those who were admitted to the respiratory Department of Respiratory Medicine, Children's Hospital of Fudan University from March 2018 to September 2022. Children with PCD were included as the PCD group, and children with situs inversus or ambiguus, cystic fibrosis (CF), bronchiectasis, chronic suppurative lung disease and asthma were included as the PCD symptom-similar group. Children who visited the Department of Child health Care and urology in the same hospital from December 2022 to January 2023 were selected as nNO normal control group. nNO was measured during plateau exhalation against resistance in three groups. Mann-Whitney U test was used to analyze the nNO data. The receiver operating characteristic of nNO value for the diagnosis of PCD was plotted and, the area under the curve and Youden index was calculated to find the best cut-off value. Results: nNO was measured in 40 patients with PCD group, 75 PCD symptom-similar group (including 23 cases of situs inversus or ambiguus, 8 cases of CF, 26 cases of bronchiectasis or chronic suppurative lung disease, 18 cases of asthma), and 55 nNO normal controls group. The age of the three groups was respectively 9.7 (6.7,13.4), 9.3 (7.0,13.0) and 9.9 (7.3,13.0) years old. nNO values were significantly lower in children with PCD than in PCD symptom-similar group and nNO normal controls (12 (9,19) vs. 182 (121,222), 209 (165,261) nl/min, U=143.00, 2.00, both P<0.001). In the PCD symptom-similar group, situs inversus or ambiguus, CF, bronchiectasis or chronic suppurative lung disease and asthma were significantly higher than children with PCD (185 (123,218), 97 (52, 132), 154 (31, 202), 266 (202,414) vs. 12 (9,19) nl/min,U=1.00, 9.00, 133.00, 0, all P<0.001). A cut-off value of 84 nl/min could provide the best sensitivity (0.98) and specificity (0.92) with an area under the curve of 0.97 (95%CI 0.95-1.00, P<0.001). Conclusions: nNO value can draw a distinction between patients with PCD and others. A cut-off value of 84 nl/min is recommended for children with PCD.

Otological Manifestations in Adults with Primary Ciliary Dyskinesia: A Controlled Radio-Clinical Study.

Primary ciliary dyskinesia (PCD) is a rare genetical disease characterized by an abnormal structure or function of the cilia, causing sinusitis, otitis, and bronchiectasis. Hearing loss affects 60% of PCD patients, but data are lacking concerning hearing and temporal bone imaging in adults. Our aim was to describe clinical and radiological ear disease in adults with genetically confirmed PCD. Data were recorded from January 2018 to December 2019. PCD patients were compared with controls with bronchiectasis without PCD. Clinical examination included otomicroscopy and auditory tests. A temporal bone CT scan (TBCT) was systematically performed. Seventeen patients (34 ears) were included in each group. The eardrums were abnormal in 25 (74%) PCD ears versus 8 (24%) ears in the controls (p < 0.05). Conductive hearing loss was more frequent in the PCD group (24% vs. 12% in controls). TBCT were abnormal in 94% PCD patients vs. 32% in the controls (p < 0.05). The Main CT-scan images in PCD were middle ear inflammation (65%), mastoid condensation (62%), or ossicular anomalies (35%). With its excellent sensitivity, TBCT gives typical arguments for PCD diagnosis, adding otological signs to the usual sinus CT signs (hypoplasia, aplasia). Systematic TBCT could be useful in the initial evaluation of patients with suspicion of PCD.

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

We aimed to investigate depression, burnout, attitude, and burden of caregivers of children with cystic fibrosis (CF), and especially caregivers of children with primary ciliary dyskinesia (PCD) due to limited number of studies on this topic, and to compare them according to their children's clinical status. Clinical features and demographic data of children and their families were asked from caregivers in four pediatric pulmonology centers. Beck Depression Inventory, Maslach Burnout Inventory, Zarit Caregiver Burden Scale, and Parental Attitude Research Instrument were administered to caregivers in both groups. Results were compared between the two groups. In total, 131 children with CF and 39 with PCD and their caregivers were involved in the study. All primary caregivers were mothers in both groups. Depression, burnout, and burden scores of mothers of children with CF were significantly higher than mothers of children with PCD (p = 0.017, p = 0.024, p = 0.038, respectively). Burnout was higher in both CF and PCD groups with low family income (p = 0.022, p = 0.034). Number of hospital visits in the previous 6 months was correlated with burnout in both CF and PCD groups (r = 0.207, p = 0.034; r = 0.352, p = 0.044). Although mothers with children with CF have higher levels of depression, burnout, burden, and negative attitudes towardchildren than mothers with children with PCD, these are also significantly high in mothers with children with PCD. Psychological problems of mothers of children with CF and PCD may increase with frequent hospital visits, hospitalizations, low family income, number of children, and chronic disease in another child.

Comparison of the Lung Clearance Index in Preschool Children With Primary Ciliary Dyskinesia and Cystic Fibrosis

Previous studies showed that the lung clearance index (LCI) determined by multiple-breath washout (MBW) is sensitive to detecting early lung disease in preschool children with cystic fibrosis (CF). In preschool children with primary ciliary dyskinesia (PCD), data on the onset and severity of lung disease and on the sensitivity of the LCI as a noninvasive quantitative outcome measure remain limited. Is MBW feasible and sensitive to detect ventilation inhomogeneity in preschool children with PCD? This was a prospective, cross-sectional, multicenter study and included preschoolers with PCD, preschoolers with CF, and healthy control (HC) participants. LCI was determined using nitrogen MBW and was compared among the three groups. LCI was determined in 27 children with PCD, 34 children with CF, and 30 HC participants (mean age, 4.8 years; range, 2.2-6.9 years). The LCI in preschool children with PCD was increased (median, 9.1; 95%CI, 8.6-10.3) compared with HC participants (median, 7.0; 95%CI, 6.7-7.1; P< .0001), but did not differ from preschool children with CF (median, 8.6; 95%CI, 8.4-9.7; P= .71). The feasibility in the PCD group was 93.1%and was similar to that in the CF group (91.9%) and in HC participants (85.7%; P= .55). This study demonstrated early onset of lung disease in preschool children with PCD and indicated that lung disease severity in PCD may be similar to that in CF during preschool years. These data support a need for early diagnostic monitoring and therapy and suggest the LCI as a noninvasive diagnostic tool and as a potential end point in clinical trials testing early interventions in children with PCD.

Physical fitness and activities of daily living in primary ciliary dyskinesia: A retrospective study.

Primary ciliary dyskinesia (PCD) is a rare, hereditary, autosomal recessive disorder characterized by recurrent upper and lower respiratory tract infections. This study aimed to compare pulmonary function, respiratory muscle strength, exercise capacity, physical fitness, and activities of daily living (ADLs) retrospectively between patients with PCD and healthy controls. Data from 20 patients with PCD and 20 matched, healthy counterparts recorded between July 2015 and January 2017 were analyzed. The data evaluated and recorded included pulmonary function using a portable spirometer, respiratory muscle strength (using a mouth pressure device, exercise capacity using the incremental shuttle walk test,), physical fitness (using the Munich Fitness Test), and ADLs (using the Glittre ADL test). Pulmonary function, respiratory muscle strength, incremental shuttle walk test scores (all parameters), and total Munich Fitness Test scores were lower in the PCD group relative to controls (P < 0.05). The duration to complete the Glittre ADL test was higher in PCD patients than in healthy subjects (P < 0.05). Pulmonary function, respiratory muscle strength, exercise capacity, physical fitness, and ADL were affected by PCD. Thus, pulmonary rehabilitation regimens should be tailored according to these impacts.

Noncystic fibrosis bronchiectasis in children and adolescents: Follow-up over a decade.

Noncystic fibrosis bronchiectasis (NCFB) is still considered an "orphan disease" in pediatric age. The study describes the clinical and functional features, the instrumental, and microbial findings of a large cohort of patients with NCFB, followed in a single tertiary level hospital. Children and adolescents diagnosed with NCFB from January1, 2010 to December31, 2019 were included. Data from the diagnosis and during the years of follow-up were recorded retrospectively. One hundred and thirty-eight patients were enrolled. The most common cause of NCFB was postinfectious (33%), followed by primary ciliary dyskinesia (PCD) (30%), esophageal atresia (EA) (9.5%), and secondary immunodeficiency (9.5%). Chronic cough was the most frequent symptom. The median age of symptoms presentation was 3 years (interquartile age [IQR]: 12-84), with a precocious onset in PCD and EA groups. The median age of CT diagnosis was 9 years for all groups but PCD patients who were diagnosed at older age. Lingula, medium, upper, and lower lobes were more involved in PCD group, while diffuse distribution was observed in the postinfectious one. Microbial exams showed Pseudomonas aeruginosa colonization higher in PCD patients (22%). Despite microbial differences in airways colonization, no difference in respiratory exacerbation rate was recorded among groups. Lung function tests demonstrated the stability of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) over time, except for the secondary immunodeficiency group. The role of infections in developed countries should not be underestimated and a major effort to obtain an earlier identification of bronchiectasis should be taken. A prompt diagnosis of NFCB could help to reduce the frequency of exacerbations and improve the stability of lung function over time.

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.

Do pulmonary and extrapulmonary features differ among cystic fibrosis, primary ciliary dyskinesia, and healthy children?

Primary ciliary dyskinesia (PCD) is generally likened to cystic fibrosis (CF) due to similarities in impaired mucociliary clearance and some other symptoms. The aim of our study was to investigate pulmonary and extrapulmonary characteristics of children with CF and PCD since no studies have addressed respiratory muscle strength in children with PCD and to compare the results to those obtained from healthy age-matched controls. Pulmonary and extrapulmonary characteristics were assessed by 6-min walk test, spirometry, maximum inspiratory and expiratorypressure measurements, and knee extensor strength test in the children with CF, PCD, and healthy controls. Children with PCD and CF had similar PFT results, except forced expiratory flow between 25% and 75% of vital capacity (FEF25-75 ) which was lower in PCD (p = .04). Maximum inspiratory pressure (MIP) value was lower in the children with CF compared with the healthy controls (p = .016), MEP value of the children with PCD was worse than those with CF and healthy controls (p = .013 andp = .013), respectively. 6-min walk test (6MWT) distance of the children with CF was lower than their healthy counterparts (p = .003). Knee extensor muscle strength differed among the children with PCD, CF, and healthy control groups, but post hoc test failed to show statistical significance (p = .010). Children with CF and PCD had some impairments in pulmonary functions, respiratory muscle strength, functional capacity, and peripheral muscle strength compared with healthy children. However, the unique characteristics of each disease should be considered during physiotherapy assessment and treatment. The clinicians may especially focus on the respiratory and peripheral muscle strength of the children with PCD.

Caregiver burden in children with cystic fibrosis and primary ciliary dyskinesia

Caregiver burden impacts both the social and economic framework of society. Cystic fibrosis (CF) causes significant caregiver burden, but the current data is scarce. In the case of primary ciliary dyskinesia (PCD), even less is known. This study aims to compare the caregiver burden of the parents of patients with CF and PCD. Patients with CF and PCD between the ages of 6 to 13 and their parents were included. Patients' clinical information and parents' demographics were recorded. Caregiver burden was measured with Zarit Caregiver Burden Scale (ZCB), while the quality of life (QOL) was measured with CFQOL-revised (CFQOL-R) and PCD QOL questionnaire as the patients' age and diagnosis indicated. A total of 63 patients, 44 with CF (69%) and 85 caregivers (35 mothers, 6 fathers, and 22 mother-father dyads) participated in the study. Caregiver burden was significantly higher in mothers of the CF group with a mean ZCB of 30.5 ± 10.7 when compared to the PCD group with a mean ZCB of 21.93 ± 8.26 (P = .006). This was similar in fathers with mean ZCB of 27.5 ± 9.21 in the CF group and 20.36 ± 7.43 in the PCD group (P = .03). In correlation analyses, mothers' caregiver burden moderately and inversely correlated with CFQOL-R subscales in the CF population. Caregiver burden is significantly higher in the CF population when compared to PCD. It is correlated with pulmonary functions and QOL in patients with CF.

Developmental and behavioral problems in preschool-aged primary ciliary dyskinesia patients.

Primary ciliary dyskinesia (PCD) causes a broad spectrum of disease. This study aims to explore the developmental, behavioral, and social-emotional aspects of preschool-aged children with PCD. Fourteen PCD, 17 cystic fibrosis (CF) patients and 15 healthy subjects were enrolled. Developmental features of the participants were evaluated with Ages and Stages Questionnaire. Parents of participants filled out the Child Behavior Checklist (CBCL). The number of children screened positive for developmental delay was statistically higher in the PCD group. Higher numbers of children with PCD were screened positive for developmental delay in communication and problem-solving domains. Delay in fine motor skill domain was more common in children with PCD and CF compared to healthy subjects. There was no difference among the three groups in terms of gross motor and personal-social development. None of the children in all three groups was shown to have social-emotional problems. In CBCL, patients with CF had higher internalizing problem scores. Externalizing and total problem scores did not differ between the three groups. However, among PCD patients, children with developmental delay on more than one domain had higher externalizing and total problem scores.Conclusion: The current study revealed that positive screening for developmental delay is more common in preschool-aged PCD patients compared to patients with CF and healthy children. What is Known: • Intelligence scores of school-aged PCD patients are similar to healthy subjects despite their higher internalizing problem scores on Child Behavior Checklist (CBCL). • School-aged PCD patients exhibit higher hyperactivity and inattention findings. What is New: • Positive screening for developmental delay in communication, problem-solving and fine motor skills is more common in preschool-aged PCD patients. • Preschool-aged PCD patients screened positive for developmental delay in more than one domain have higher externalizing and total problem scores on CBCL.

Nasal Nitric Oxide in Primary Immunodeficiency and Primary Ciliary Dyskinesia: Helping to Distinguish Between Clinically Similar Diseases.

Primary ciliary dyskinesia (PCD) is a rare disorder of the mucociliary clearance leading to recurrent upper and lower respiratory tract infections. PCD is difficult to clinically distinguish from other entities leading to recurrent oto-sino-pulmonary infections, including primary immunodeficiency (PID). Nasal nitric oxide (nNO) is a sensitive and specific diagnostic test for PCD, but it has not been thoroughly examined in PID. Past publications have suggested an overlap in nNO levels among subjects with PCD and PID. We sought to determine if nNO measurements among patients diagnosed with PID would fall significantly above the established PCD diagnostic cutoff value of 77nL/min. Children > 5years old and adults with definitive PID or PCD diagnoses were recruited from outpatient subspecialty clinics. Participants underwent nNO testing by standardized protocol using a chemiluminescence analyzer and completed a questionnaire concerning their chronic oto-sino-pulmonary symptoms, including key clinical criteria specific to diagnosed PCD (neonatal respiratory distress at term birth, year-round cough or nasal congestion starting before 6months of age, any organ laterality defect). Participants included 32 patients with PID, 27 patients with PCD, and 19 healthy controls. Median nNO was 228.9.1nL/min in the PID group, 19.7nL/min in the PCD group, and 269.4 in the healthy controls (p < 0.0001). Subjects with PCD were significantly more likely to report key clinical criteria specific to PCD, but approximately 25% of PID subjects also reported at least 1 of these key clinical criteria (mainly year-round cough or nasal congestion). While key clinical criteria associated with PCD often overlap with the symptoms reported in PID, nNO measurement by chemiluminescence technology allows for effective discrimination between PID and PCD.

Comparison of Nocturnal Cough Analysis in Healthy Subjects and in Patients with Cystic Fibrosis and Primary Ciliary Dyskinesia: A Prospective Observational Study

Background: Cough is a key symptom in patients with cystic fibrosis (CF) and primary ciliary dyskinesia (PCD). Objective: The study objectives were to test whether cough is related to parameters reflecting their disease severity and whether CF and PCD differ in cough frequency. Methods: In this prospective observational study, we used a microphone-based monitoring system (LEOSound® Monitor) to count the coughs in healthy subjects (HS) and in stable patients with CF and PCD (25 subjects per group) on 2 consecutive nights. Results: The median number of coughs/h in the HS, CF, and PCD groups was 0.0, 1.3, and 0.5 on the first night and 0.0, 2.3, and 0.2 on the second night, respectively. Patients with CF and PCD coughed more than HS (p < 0.001 and p = 0.009, respectively) and CF patients coughed more than PCD patients (p = 0.023). A multivariable mixed model analysis revealed forced expiratory volume in 1 s as an independent risk factor for increased cough frequency in patients. The reliability for repeated measurements was higher for cough epochs/h than for coughs/h (intraclass correlation coefficient: 0.75 and 0.49, respectively). Conclusions: Patients with CF cough more than patients with PCD. The cough frequency in CF and PCD is associated with parameters reflecting disease severity. Cough frequency is a possible endpoint in clinical trials and cough epochs/h may be more useful than coughs/h.

Nasal Nitric Oxide Measurement and a Modified PICADAR Score for the Screening of Primary Ciliary Dyskinesia in Adults with Bronchiectasis.

Background Determining the underlying diagnosis is essential for the targeted and specific treatment of bronchiectasis. Primary ciliary dyskinesia (PCD) is a rare genetic disease, which is characterized by abnormalities in ciliary structure and/or function and which may result in bronchiectasis. The disease is probably underestimated among adults with bronchiectasis due to the fact that extensive diagnostic testing is required and that the recognition of PCD is low. Objective To evaluate a feasible screening algorithm for PCD among adults with bronchiectasis. Methods Data from all patients who presented to our bronchiectasis outpatient clinic from June 2010 until July 2016 were retrospectively analysed from our database. Nasal NO (nNO) and a modified PICADAR score (PrImary CiliAry DyskinesiA Rule) were measured and compared in the two groups of PCD-bronchiectasis and non-PCD-bronchiectasis. Results 185 of 365 patients (75 males, 110 females) had a sufficient measurement of nNO concentration and complete clinical data and were eligible for analysis. The mean (SD) nNO concentration in nL/ml was significant lower in the PCD group compared to the non-PCD group (25 [31] and 227 [112] nL/min, respectively; p < 0.001). A nNO level of 77 nL/min had the best discriminative value to differentiate between the two groups. Patients with PCD had a significant higher modified PIDACAR score than patients without PCD (5 2 and 1 1, respectively [p < 0.001]). Using ROC curve analysis, the modified PICADAR score of 2 had the best discriminative value with a sensitivity of 1.00 and a specificity of 0.89. Conclusions Low nNO concentration and the modified PICADAR score are suitable and cheap screening tests for PCD in adults with bronchiectasis.

Population specificity of the DNAI1 gene mutation spectrum in primary ciliary dyskinesia (PCD)

BackgroundMutations in the DNAI1 gene, encoding a component of outer dynein arms of the ciliary apparatus, are the second most important genetic cause of primary ciliary dyskinesia (PCD), the genetically heterogeneous recessive disorder with the prevalence of ~1/20,000. The estimates of the DNAI1 involvement in PCD pathogenesis differ among the reported studies, ranging from 4% to 10%.MethodsThe coding sequence of DNAI1 was screened (SSCP analysis and direct sequencing) in a group of PCD patients (157 families, 185 affected individuals), the first ever studied large cohort of PCD patients of Slavic origin (mostly Polish); multiplex ligation-dependent probe amplification (MLPA) analysis was performed in a subset of ~80 families.ResultsThree previously reported mutations (IVS1+2-3insT, L513P and A538T) and two novel missense substitutions (C388Y and G515S) were identified in 12 families (i.e. ~8% of non-related Polish PCD patients). The structure of background SNP haplotypes indicated common origin of each of the two most frequent mutations, IVS1+2-3insT and A538T. MLPA analysis did not reveal any significant differences between patients and control samples. The Polish cohort was compared with all the previously studied PCD groups (a total of 487 families): IVS1+2-3insT remained the most prevalent pathogenetic change in DNAI1 (54% of the mutations identified worldwide), and the increased global prevalence of A538T (14%) was due to the contribution of the Polish cohort.ConclusionsThe worldwide involvement of DNAI1 mutations in PCD pathogenesis in families not preselected for ODA defects ranges from 7 to 10%; this global estimate as well as the mutation profile differs in specific populations. Analysis of the background SNP haplotypes suggests that the increased frequency of chromosomes carrying A538T mutations in Polish patients may reflects local (Polish or Slavic) founder effect. Results of the MLPA analysis indicate that no large exonic deletions are involved in PCD pathogenesis.

The secondary nature of ciliary (dis)orientation in secondary and primary ciliary dyskinesia

ObjectiveCiliary orientation (COR) is an important parameter of mucociliary clearance and ciliary disorientation has been reported in cases of acquired abnormalities [secondary ciliary dyskinesia (SCD)] and in a very few cases as the single abnormality in primary ciliary dyskinesia (PCD). The etiology, pathogenesis, consequences and relevance of ciliary (dis)orientation are still unclear. Material and MethodsTo elucidate the primary or secondary nature of ciliary (dis)orientation, COR was measured in 179 non-PCD and 59 PCD patients. COR was measured in biopsies and after ciliogenesis in culture and was correlated with a number of functional and ultrastructural parameters. COR was defined as the SD of the angles of lines through the central pair of microtubules using transmission electron microscopy. Internationally accepted normal values for COR are ≤20°; COR values of 20–35° indicate increased disorientation; and COR values >35° represent a random orientation. ResultsFor non-PCD biopsies, COR increased with increasing SCD, from 15±7° (n=54) for normal (<5%) SCD to 28±8° (n=16) for severe (>25%) SCD. No correlation was found between COR and ciliary beat frequency. However, increased COR values (28±8°) were found for immotility (n=8), compared to (coordinated) ciliary activity (19±9°) (n=121). After ciliogenesis no ultrastructural abnormalities were found and COR was normal (13±5°; n=308). COR can therefore be considered to be secondary in non-PCD and correlates with SCD percentage and ciliary motility. In biopsies from PCD patients with dynein deficiency and with normal ultrastructure, COR was increased, to 28±11° (n=32) and 21±7° (n=15), respectively, and in cases with central pair abnormalities COR was random (38±11°; n=12). After ciliogenesis COR remained random in the PCD group with central pair abnormalities (38±9°; n=15), and was increased in the PCD groups with dynein deficiency (24±10°; n=35) and normal ultrastructure (25±8°; n=17). Ciliary disorientation was never found as the single abnormality. Conclusion COR can be considered to be secondary in PCD. Both ciliary (im)motility and SCD percentage contribute to COR.

Plasma membrane polarity of polymorphonuclear leucocytes from children with primary ciliary dyskinesia.

Polymorphonuclear leucocytes (PMN) from subjects with primary ciliary dyskinesia (PCD) can have abnormal locomotory systems. The locomotory activity of PMN is the result of biochemical events mediated by the plasma membrane. In this study we investigated plasma membrane polarity of PMN from children with PCD. Membrane polarity was studied in 11 children with PCD and in healthy controls by measuring the steady-state fluorescence excitation and emission spectra of 2-dimethylamino[6-lauroyl]naphthalene (Laurdan), which is known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer, displaying spectral sensitivity to the polarity of its surroundings. Laurdan shows a marked steady-state emission red shift in polar solvents, with respect to nonpolar solvents. Moreover, the effect of the microtubule disassembling agent colchicine on PMN membrane polarity was evaluated. Our results show a red shift of the fluorescence excitation and emission spectra of Laurdan in PMN from the PCD group with respect to the control group. These data indicate an increase in membrane polarity of PMN from the PCD group. Treatment of PMN with colchicine induced a red shift in the Laurdan excitation and emission spectra with the same trend observed in PMN from the PCD group. PMN from children with PCD are characterized by an increased plasma membrane polarity. These changes could be the basis of the modifications in the locomotory activities of PMN. The observed alterations may be attributed to abnormalities in the cytoskeleton.

Airway response of children with primary ciliary dyskinesia to exercise and beta2-agonist challenge.

In primary ciliary dyskinesia (PCD), chest physiotherapy for airway clearance is essential. Exercise and inhaled beta2-agonists can produce bronchodilation thereby augmenting physiotherapy. However, both can also cause bronchoconstriction, and the effects of these stimuli in PCD are not known. In a preliminary study, the mean coefficients of variation for forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) in children with PCD were determined. They were 5.4%, 4.4% and 8.4%, respectively. Twelve children with PCD and 12 normal children performed pulmonary functions under resting conditions; during and after a validated treadmill exercise test; and before and 15 min after 200 microg of inhaled salbutamol. At baseline, FEV1, FVC, forced mid-expiratory flow (FEF25-75%) and PEFR were significantly reduced in the PCD group compared with the control group. Exercise produced a significant increase in PEFR in the PCD group. There was no significant difference between the groups in response to salbutamol. Within the PCD group, exercise produced a significantly greater increase in PEFR than beta2-agonist therapy. In conclusion, in children with primary ciliary dyskinesia there is evidence of obstructive pulmonary disease. In these children, exercise is a more potent stimulus for bronchodilation than by inhaled beta2-agonists. Enhancement of airway clearance may best be achieved by encouraging patients to exercise before physiotherapy rather than by inhaling beta2-agonists, but the effects of each should be assessed for each individual before instigating treatment.