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International audience; Nasal Nitric Oxide (nNO) measurement is recommended to screen for Primary Ciliary Dyskinesia (PCD) in subjects with suggestive history and symptoms. Clinical use of alternative methods (ie breath hold (BH), tidal breathing (TB)) in children unable to perform the gold standard slow Exhalation against a Resistance (ER) method has not been sufficiently evaluated. We extracted retrospectively (2013-2019) 454 files (374 subjects) containing nNO results. Median [IQR] age at inclusion was 7.0 [4.7 - 11.0] years, 105 (28.1%) children were younger than 5 years. ER or BH methods were more frequently mastered by children older than 5 years compared to younger children (69.4% and 52.7% versus 21% and 5.6%, respectively, P < 0.0001), the latter succeeding only in TB measurement in 77.4% of cases. In 130 files with both ER and BH measurements (nNO-ER and nNO-BH), nNO-BH was 102 [96.2;108.3]% that of nNO-ER. In 175 files including nNO-ER and nNO-TB measurements, nNO-TB was 64.4 [IQR: 53.7;80.4]% that of nNO-ER with an excellent correlation between nNO values (r = 0.94 [95%CI 0.91;0.95]; P

Background: North American standardised testing protocols assume that only nasal Nitric Oxide (nNO) measured during expiration against a mouth resistance (ExRe) in children older than 5 years is a reliable tool for diagnosis of Primary Ciliairy Dyskinesia (PCD). Objectives: To establish the relevance of tidal breathing (TB) nNO measurement as a first line test in young children. Methods: Monocenter retrospective study (2013 - 2019) based on the records of children seen for suspicion of PCD. nNOExRe and nNOTB were measured using CLD 88 sp (EcoPhysics, Suisse). Results: Nasal NO measurement was possible on 460 occasions in 382 children (median [IQR] (range) age of 7.1 [4.8 to 11.1](0.1 to 19.4) years, 167 (43.7%) females). Recorded numbers of nNOExRe and nNOTB were 247 (53%) and 355 (77%); respectively, with 158 (34%) nNOTB on isolation. One hundred and five children 5 years or less performed 24 (19%) nNOExRe and 119 (94%) nNOTB. Among the 81 children with only nNOTB result and based on all available investigations, PCD diagnosis was excluded (n=58, nNOTB 298 [199;391]ppb), confirmed or very probable but pending (n=12 and n=3, nNOTB 42 [28;69]ppb), or unknown (n=8, nNOTB 129 [31;239]ppb). Among children with excluded versus confirmed / pending PCD diagnosis, frequencies of ciliary beat study, electron microscopy, and genetic testing were 15 (26%) versus 9 (60%), 3 (20%) versus 8 (53%), and 0 versus 8 (53%), respectively. Conclusion: In children less than 5 years, the success rate of nNOTB measurements was 94% and allowed stopping PCD workup in 74% of cases in children with medium-low clinical suspicion.

BackgroundPrimary ciliary dyskinesia (PCD) is a rare genetic disorder resulting in abnormal ciliary motility/structure, extremely heterogeneous at genetic and ultrastructural levels. We aimed, in light of extensive genotyping, to identify specific and quantitative ciliary beating anomalies, according to the ultrastructural phenotype.MethodsWe prospectively included 75 patients with PCD exhibiting the main five ultrastructural phenotypes (n=15/group), screened all corresponding PCD genes and measured quantitative beating parameters by high-speed video-microscopy (HSV).ResultsSixty-eight (91%) patients carried biallelic mutations. Combined outer/inner dynein arms (ODA/IDA) defect induces total ciliary immotility, regardless of the gene involved. ODA defect induces a residual beating with dramatically low ciliary beat frequency (CBF) related to increased recovery stroke and pause durations, especially in case of DNAI1 mutations. IDA defect with microtubular disorganisation induces a low percentage of beating cilia with decreased beating angle and, in case of CCDC39 mutations, a relatively conserved mean CBF with a high maximal CBF. Central complex defect induces nearly normal beating parameters, regardless of the gene involved, and a gyrating motion in a minority of ciliated edges, especially in case of RSPH1 mutations. PCD with normal ultrastructure exhibits heterogeneous HSV values, but mostly an increased CBF with an extremely high maximal CBF.ConclusionQuantitative HSV analysis in PCD objectives beating anomalies associated with specific ciliary ultrastructures and genotypes. It represents a promising approach to guide the molecular analyses towards the best candidate gene(s) to be analysed or to assess the pathogenicity of the numerous sequence variants identified by next-generation-sequencing.

International audience; Cilia and flagella are evolutionarily conserved organelles whose motility relies on the outer and inner dynein arm complexes (ODAs and IDAs). Defects in ODAs and IDAs result in primary ciliary dyskinesia (PCD), a disease characterized by recurrent airway infections and male infertility. PCD mutations in assembly factors have been shown to cause a combined ODA-IDA defect, affecting both cilia and flagella. We identified four loss-of-function mutations in TTC12, which encodes a cytoplasmic protein, in four independent families in which affected individuals displayed a peculiar PCD phenotype characterized by the absence of ODAs and IDAs in sperm flagella, contrasting with the absence of only IDAs in respiratory cilia. Analyses of both primary cells from individuals carrying TTC12 mutations and human differentiated airway cells invalidated for TTC12 by a CRISPR-Cas9 approach revealed an IDA defect restricted to a subset of single-headed IDAs that are different in flagella and cilia, whereas TTC12 depletion in the ciliate $Paramecium\ tetraurelia$ recapitulated the sperm phenotype. Overall, our study, which identifies TTC12 as a gene involved in PCD, unveils distinct dynein assembly mechanisms in human motile cilia versus flagella.

Introduction: Primary ciliary dyskinesia (PCD) is a rare genetic disease characterized by abnormalities in ciliary function, responsible for abnormal mucus clearance and repeated respiratory tract infections. The potential benefit of macrolide antibiotics has been evaluated in variety of chronic respiratory diseases. The efficacy of long-term azithromycine (AZT) has never been studied in PCD patients. Aim: The aim of this retrospective study was to investigate the effect of long-term AZT on the decrease in annual number of pulmonary exacerbations in children with PCD. Materials and Methods: All of our patients followed in our Pediatric center and who received low dose of AZT for more than 6 months were included. The clinical data (rate of pulmonary exacerbations, lung function analyses, ENT symptoms and changes in the airways bacterial colonizations) were collected from 1 year before and up to 5 years after the initiation of the AZT treatment. Results: A total of 31 children were included (11 years +/- 4 years). After 1 year, we observed a significant reduction in the annual number of pulmonary exacerbations (on average 1.7 +/- 2.7 exacerbations per year before treatment versus 0.5 +/- 1 exacerbation per year after 1 year of treatment) and a significant improvement in ENT symptoms. However, the lung function decline was not modified. No difference in the airways colonizations by pathogens, nor emerging antibiotic resistance were observed during the treatment. Conclusion: Our study showed a clinical improvement of PCD children treated by long term AZT. Those results must be confirmed by a larger multicenter study, such as the one currently conducted by the BEAT PCD group.

International audience; Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) both entail bronchiectasis and pulmonary impairment as measured using spirometry, during childhood. We aimed at looking whether blood gas exchanges progressed differently between CF and PCD children in a retrospective study of repeated measurements. Comparisons between groups (Wilcoxon-Mann-Whitney and Chi-squared tests) and a mixed linear model, adjusted for age, evaluated associations between diseases and PaO2, PaCO2, or PaO2-PaCO2 ratio.Among 42 PCD and 73 CF children, 62% and 59% had respectively bronchiectasis (P = 0.75). Spirometry and blood gases were similar at inclusion (PaO2 median [IQR] PCD −1.80 [−3.40; −0.40]; CF −1.80 [−4.20; 0.60] z-scores; P = 0.72). PaO2 and PaO2-PaCO2 ratio similarly and significantly decreased with age in both groups (P

High speed videomicroscopy (HSV) becomes a key test in primary ciliary dyskinesia (PCD), providing a qualitative evaluation and recently a quantitative analysis of ciliary beating. We aimed to correlate ultrastructural phenotype and ciliary beating Method: 75 PCD patients were prospectively included to reach 15 patients per main ultrastructural phenotypes (combined outer/inner dynein arm defect, outer dynein arm defect, inner dynein arm defect with microtubular disorganization, central complex defect and PCD with normal ultrastructure). Ciliary beating was assessed by the proportion of beating ciliated edges, the ciliary beat frequency (CBF), a qualitative evaluation and a quantitative analysis allowing measuring objective parameters Result: Combined outer/inner dynein arm defect induced a total ciliary immotility, whatever the involved gene; (ii) Outer dynein arm defect induced a minimal residual beating with dramatically low CBF related to increased pause and recovery duration, especially in case of DNAI1 mutations; (iii) Inner dynein arm defect induced a weak proportion of ciliated edges still beating, a decreased beating angle and furthermore a relatively conserved CBF in case of CCDC39 mutations; (iv) Central complex defect induced nearly normal quantitative parameters with a circular gyrating motion in a minority of ciliated edges, whatever the involved gene; (v) PCD with normal ultrastructure induced a wide discrepancy in beating parameters but a frequent increased CBF Conclusion: Quantitative analysis by HSV allows objectively detecting abnormal values of ciliary beating parameters characteristic of each of the main ultrastructural phenotypes reported in PCD.

Background and Objectives Functional and structural lung evaluations are part of the follow-up of patients with primary ciliary dyskinesia (PCD). We aimed to evaluate transversal and longitudinal relationships between lung function test (LFT) and chest computed tomography (CT) in children with PCD, in stable clinical condition. Materials and Methods Data from children followed in the French National Center were retrospectively collected. Inclusion criteria were (i) definitive diagnosis of PCD, (ii) age less than 15 years at the beginning of follow-up, (iii) at least 8 years of follow-up, (iv) at least two couples of concurrent CT and LFT available in a phase of clinical stability of the lung disease without modification of the treatment regimen in the last 4 weeks. Twenty children (median age at entry 4.6 years, median follow-up 15.4 years) were included. Concurrent LFT (blood gas and spirometry) and CT (score) results were recorded. Results LFT indices (PaO2 (n = 210), FVC, FEV1, FEF2575% (n = 195)) significantly decreased with age, and the mean annual decrease (z-score (% predicted)) was −0.17 (−0.49%), −0.09 (−0.50%), −0.10 (−0.89%), and −0.07 (−1.73%), respectively. First CT (median age 8.7 years) revealed bronchiectasis (70%), mucous plugging (70%), peribronchial thickening (90%), parenchymal abnormalities (65%), and hyperinflation (50%). CT scores (n = 74) significantly increased with age, and was negatively correlated to PaO2, FVC, FEV1, and FEF2575% longitudinal changes. Conclusion In stable clinical condition, functional, and structural progressive impairments significantly correlated in children with PCD. Further prospective studies, including large populations of patients with various levels of disease severity, are needed to confirm whether lung function follow-up can be used to adjust CT frequency and help at minimizing the radiation burden in children with a good life expectancy. Pediatr Pulmonol. 2012. 47:816–825. © 2012 Wiley Periodicals, Inc.

Introduction: Capillary partial pressure of O 2 (PcapO 2 ) was found to decrease with age in children with primary ciliary dyskinesia (PCD) while PcapCO 2 remained steady. Objectives: To further explore the relationship between PcapO 2 , nasal Nitric Oxide (nNO) output and lung function (LF) in children with PCD. Patients and methods: Retrospective monocentric study in children referred to our national paediatric reference center for rare lung diseases for PCD diagnostic work-up, and in whom ear lobe capillary blood gas was available along with nNO and/or LF measurements. Results: 30 PCD children were included (18 girls, median age 11.5 (0.7 to 18.2) years). Median PcapO 2 was -1.9 (-5.2 to 2.2) z-score, median nNO in 27 children was 61 (20.3 to 697) ppb and median FEV 1 in 24 children was -2 (-4.7 to 2.18) z-score. In univariate analysis, there was a significant relationship between PcapO 2 and nNO, age, and LF indices (see table). In multivariate analysis, there was a significant relationship between PcapO 2 and nNO (p=0.02), and FEF 75% (p Conclusion: In the study children, low PcapO 2 was correlated with decrease nNO output and one LF indice. This could explain the early occurrence of hypoxemia in the course of PCD disease.

International audience; Primary ciliary dyskinesia (PCD) is a rare autosomal-recessive condition resulting from structural and/or functional defects of the axoneme in motile cilia and sperm flagella. The great majority of mutations identified so far involve genes whose defects result in dynein-arm anomalies. By contrast, PCD due to CC/RS defects (those in the central complex [CC] and radial spokes [RSs]), which mightbe difficult to diagnose, remains mostly unexplained. We identified non-ambiguous RSPH3 mutations in 5 of 48 independent families affected by CC/RS defects. RSPH3, whose ortholog in the flagellated alga Chlamydomonas reinhardtii encodes a RS-stalk protein, is mainly expressed in respiratory and testicular cells. Its protein product, which localizes within the cilia of respiratory epithelial cells, was undetectable in airway cells from an individual with RSPH3 mutations and in whom RSPH23 (a RS-neck protein) and RSPH1 and RSPH4A (RS-head proteins) were found to be still present within cilia. In the case of RSPH3 mutations, high-speed-videomicroscopy analyses revealedthe coexistence of immotile cilia and motile cilia with movements of reduced amplitude. A striking feature of the ultrastructural phenotype associated with RSPH3 mutations is the near absence of detectable RSs in all cilia in combination with a variable proportion of cilia with CC defects. Overall, this study shows that RSPH3 mutations contribute to disease in more than 10% of PCD-affected individualswith CC/RS defects, thereby allowing an accurate diagnosis to be made in such cases. It also unveils the key role of RSPH3 in the proper building of RSs and the CC in humans.

Introduction: Primary ciliary dyskinesia (PCD) is a rare disease classically transmitted as an autosomal recessive trait and characterised by recurrent airway infections due to abnormal ciliary structure and function. To date, only two autosomal genes, DNAI1 and DNAH5 encoding axonemal dynein chains, have been shown to cause PCD with defective outer dynein arms. Here, we investigated one non-consanguineous family in which a woman with retinitis pigmentosa (RP) gave birth to two boys with a complex phenotype combining PCD, discovered in early childhood and characterised by partial dynein arm defects, and RP that occurred secondarily. The family history prompted us to search for an X linked gene that could account for both conditions. Results: We found perfect segregation of the disease phenotype with RP3 associated markers (Xp21.1). Analysis of the retinitis pigmentosa GTPase regulator gene ( RPGR ) located at this locus revealed a mutation (631_IVS6+9del) in the two boys and their mother. As shown by study of RPGR transcripts expressed in nasal epithelial cells, this intragenic deletion, which leads to activation of a cryptic donor splice site, predicts a severely truncated protein. Conclusion: These data provide the first clear demonstration of X linked transmission of PCD. This unusual mode of inheritance of PCD in patients with particular phenotypic features (that is, partial dynein arm defects and association with RP), which should modify the current management of families affected by PCD or RP, unveils the importance of RPGR in the proper development of both respiratory ciliary structures and connecting cilia of photoreceptors.

International audience; Primary ciliary dyskinesia (PCD) is an inherited disease related to ciliary dysfunction, with heterogeneity in clinical presentation and in ciliary ultrastructural defect. Our study intended to determine if there are phenotypic differences in patients with PCD based on ciliary ultrastructural abnormality. In this retrospective study carried out among 60 children with a definitive diagnosis of PCD, we analyzed clinical, radiological, and functional features at diagnosis and at last recorded visit, according to cilia defect (absence of dynein arms: DAD group, n = 36; abnormalities of the central complex: CCA group, n = 24). Onset of respiratory symptoms occurred later in the CCA than in the DAD group (9.5 versus 0.5 months, p = 0.03). Situs inversus was only observed in the DAD group, while respiratory disease in siblings were more frequent in the CCA group (p = 0.003). At diagnosis, clinical presentation was more severe in the CCA group: frequency of respiratory tract infections (p = 0.008), rhinosinusitis (p = 0.02), otitis complications (p = 0.0001), bilateral bronchiectasis (p = 0.04), and number of hypoxemic patients (p = 0.03). Pulmonary function remained stable in both groups, but outcome was better in the CCA than in the DAD group: less antibiotic therapy and hypoxemic patients (p = 0.004). In conclusion, our results underlined the relationship between the severity of clinical presentation and the ultrastructural ciliary defect.

Background Primary Ciliary Dyskinesia (PCD) is a inherited disorder characterized by abnormal ciliary structure/function, responsible for impaired muco-ciliary transport and infertility. The diagnosis is often delayed for several years though PCD is a rare (~1/20,000) and heterogeneous disease. We elaborated recommendations aiming at improving the quality and efficacy of PCD diagnosis. Methods A multicentric working group, created in 2009 within the French National Centre for Rare Respiratory Diseases, elaborated precise and practical algorithm for PCD diagnosis, based on their experience and the recent literature. It includes adults and paediatric physicians, biologists and technicians involved in PCD, dealing since many years with the difficulties to confirm this diagnosis.

International audience; Primary ciliary dyskinesia (PCD) is a group of autosomal-recessive disorders resulting from cilia and sperm-flagella defects, which lead to respiratory infections and male infertility. Most implicated genes encode structural proteins that participate in the composition of axonemal components, such as dynein arms (DAs), that are essential for ciliary and flagellar movements; they explain the pathology in fewer than half of the affected individuals. We undertook this study to further understand the pathogenesis of PCD due to the absence of both DAs. We identified, via homozygosity mapping, an early frameshift in LRRC6, a gene that encodes a leucine-rich-repeat (LRR)-containing protein. Subsequent analyses of this gene mainly expressed in testis and respiratory cells identified biallelic mutations in several independent individuals. The situs inversus observed in two of them supports a key role for LRRC6 in embryonic nodal cilia. Study of native LRRC6 in airway epithelial cells revealed that it localizes to the cytoplasm and within cilia, whereas it is absent from cells with loss-of-function mutations, in which DA protein markers are also missing. These results are consistent with the transmission-electron-microscopy data showing the absence of both DAs in cilia or flagella from individuals with LRRC6 mutations. In spite of structural and functional similarities between LRRC6 and DNAAF1, another LRR-containing protein involved in the same PCD phenotype, the two proteins are not redundant. The evolutionarily conserved LRRC6, therefore, emerges as an additional player in DA assembly, a process that is essential for proper axoneme building and that appears to be much more complex than was previously thought.

To analyze otologic features in patients with primary ciliary dyskinesia (PCD) aged 0 to 18 years and to evaluate the correlation between ultrastructural defects and severity of otologic features.Retrospective study.Pediatric referral center.Fifty-eight patients with PCD were evaluated in the following 4 age intervals: group 1, preschool (≤ 5 years [n = 47]); group 2, school (6-11 years [n = 50]); group 3, teenagers (12-17 years [n = 34]); and group 4, young adults (≥ 18 years; 27 years for the oldest [n = 10]). Follow-up was 2 to 6 years in each age group; 26 patients had total follow-up of more than 12 years. Ultrastructural defects occurred in the outer dynein arm (n = 33), the inner dynein arm (n = 13), and the central complex (n = 11). One patient had typical Kartagener syndrome with typical PCD features but normal ciliary ultrastructure.Frequency of acute otitis media, otitis media with effusion, otorrhea, chronic otitis media, hearing loss, and middle ear surgery and type of antibiotic regimen according to age and type of defect.Recurrent acute otitis media decreased from group 1 (32 of 47 [68%]) to group 4 (0 of 10 [0%]) (P.001). Otitis media with effusion was more severe in groups 1 through 3 than in group 4 (P = .02). Otorrhea decreased in group 4: 30% vs 80% (3 of 10 vs 36 of 41) in the other groups (P.001). Half of the patients with tympanostomy tubes eventually had tympanic perforation. Hearing loss was moderate in groups 1 through 3 and mild in group 4. Continuous antibiotic therapy could be slightly reduced only in group 4. Central complex defect was a significant marker of severity for all these criteria.Despite continuous antibiotic therapy, the middle ear condition in PCD remained severe throughout childhood, with improvement only after age 18 years. Armstrong grommet placement did not improve the middle ear condition. Central complex defect is a marker of severity.

Background. Ciliary ultrastructural defects with total lack of dynein arms (DA) cause abnormal mucociliary function leading to the chronic infections observed in primary ciliary dyskinesia. The role of partial ciliary ultrastructural defects, especially those involving the central complex, and their relationship with respiratory symptoms have been less thoroughly investigated. Objective. In a pediatric population with partial ciliary defects, we determined the relationship(s) between ultrastructural findings, ciliary motility, and clinical and functional features, and evaluated the outcome of this population. Design. We analyzed the clinical presentation and pulmonary function of 43 children with chronic bronchitis and partial ultrastructural defects (from 15% to 90%) of their respiratory cilia demonstrated on bronchial biopsies. The study population was divided into 3 groups according to ciliary ultrastructure: the main ultrastructural defect concerned the central complex in 23 patients (CC group), peripheral microtubules in 8 patients (PMT group), and DA in 12 patients (DA group). Results. The percentage of ciliary defects was lower in the PMT group than in the CC and DA groups. Patients in the PMT group had less severe disease with frequent normal ciliary motility. Patients in the CC group had initially a higher incidence of respiratory tract infections, extensive bronchiectasis frequently requiring surgery, and arguments in favor of a congenital origin (high proportion of sibling form). Partial absence of DA, although of congenital origin, was associated with a good prognosis. In all groups, follow-up showed that the functional prognosis remained good with appropriate treatment. Conclusions. In children with chronic respiratory infections, presence of situs inversus, sibling form, obstructive pulmonary syndrome, or bronchiectasis required ultrastructural analysis, regardless of ciliary motility. Detection of CC abnormalities is a marker of severity and required intensive therapy and close follow-up.

International audience