Primary ciliary dyskinesia: current state of the art.

Primary ciliary dyskinesia (PCD) is usually inherited as an autosomal recessive disorder and presents with upper and lower respiratory tract infection, and mirror image arrangement in around 50% of cases. Cilia dysfunction is also implicated in a wider spectrum of disease, including polycystic liver and kidney disease, central nervous system problems including retinopathy and hydrocephalus, and biliary atresia. Cilia are complex structures, containing more than 250 proteins; recent studies have begun to locate PCD genes scattered throughout the genome. Screening tests for PCD include nasal nitric oxide and in vivo tests of ciliary motility such as the saccharin test. Specific diagnosis requires examination of cilia by light and electron microscopy, with epithelial culture in doubtful cases. This is only available in supra-regional centres, recently centrally funded by the National Commissioning Group. Treatment is not evidence based and recommendations are largely extrapolated from cystic fibrosis and other suppurative lung diseases.     

Ciliary defects and genetics of primary ciliary dyskinesia

Cilia are evolutionarily conserved structures that play key roles in diverse cell types. Motile cilia are involved in the most prominent ciliopathy called primary ciliary dyskinesia (PCD) that combines respiratory symptoms, male infertility, and, in nearly 50% cases, situs inversus. The diagnosis of PCD relies on the identification of ciliary abnormalities that mainly concern outer and/or inner dynein arms (ODA, IDA). PCD is a genetic condition, usually inherited as an autosomal recessive trait. To date, six genes have been clearly implicated in PCD. Two “major” genes, DNAI1 and DNAH5, underlie PCD in nearly half of the patients with ODA defects, whereas RPGR, DNAH11 and TXNDC3 are implicated in rare families with specific phenotypes (retinitis pigmentosa, abnormal beating of structurally normal cilia, and situs ambiguous, respectively). The relative contribution of DNAI2 is currently being assessed. In all the other patients with ODA or other ultrastructural defects, the causative genes remain to be identified.     

Nasal ciliary investigations for the diagnosis of primary ciliary dyskinesia in children]

Primary ciliary dyskinesia (PCD) is an autosomal recessive disorder, characterized by chronic infections of the upper and lower airways, associated in 50% of cases with situs inversus, therefore, corresponding to Kartagener's syndrome. PCD is suspected on clinical features, including bronchitis, rhinosinusitis and chronic otitis media beginning in early childhood. The recurring infections eventually lead to bronchiectasis. The clinical features of PCD have been ascribed to primary defects in cilia, which lead to impairment of mucociliary clearance. Ciliary investigations looking for abnormalities in ciliary motion and ultrastructure can be easily performed at nasal level. Quantitative ultrastructural study of cilia is performed in cases of abnormal ciliary motion and/or clinical symptoms highly suggestive of PCD. In PCD, all or most of the cilia are abnormal, all bearing the same ultrastructural defects, mainly concerning dynein arms. In older children, the detection of a very low nasal NO output could also be useful for the diagnosis of PCD. As soon as the ciliary investigations are easy to perform at the nasal level, they could help for a better detection of PCD. This strategy could be especially useful in cases of atypical presentations, which are underestimated as a cause of recurrent airway infections. Diagnosis of PCD is important in order to prevent the development of bronchiectasis and to avoid any unnecessary procedure.     

Neonatal respiratory distress syndrome – a sign of primary ciliary dyskinesia?

Primary ciliary dyskinesia (PCD) is a clinically heterogeneous disease. In most cases, its clinical manifestation in children is rather unspecific: chronic infectious rhinosinusitis, recurrent acute infections of the upper and lower airways and chronic otitis media with effusion. Between 1990 and 1998 ten patients were diagnosed as PCD. Nine presented a neonatal respiratory distress syndrome (NRDS) of unknown cause. Six of these patients were newborns treated in the intensive care unit, one of them needed mechanical ventilation. The few cases already described in the literature and the experience with our patients support the possible association of NRDS with PCD. Conclusion Neonatal respiratory distress syndrome of unknown cause should be added to the list of clinical presentation of primary ciliary dyskinesia, and if further signs and symptoms are indicative of primary ciliary dyskinesia, investigations to explore this disorder are warranted. Received: 8 December 1999 and in revised form: 13 May and 13 June 2000 / Accepted: 14 June 2000     

Primary ciliary dyskinesia diagnosed on nasal mucosal biopsy in two newborns

Primary ciliary dyskinesia (PCD) is a genetic disease that causes abnormalities in ciliary structure and/or function. Ciliated cells line the upper and lower respiratory tracts and the Eustachian tube. Impairment of mucus clearance at these sites leads to sinusitis, repeated pulmonary infections, bronchiectasis, and chronic otitis media. Situs inversus occurs randomly in approximately 50% of subjects with PCD. The triad of situs inversus, bronchiectasis and sinusitis is known as Kartagener syndrome. PCD is usually an autosomal recessive disease, but occasional instances of X‐linked transmission have been reported. Specific diagnosis requires examination of ciliary function or structure on light and electron microscopy. Early diagnosis and respiratory management are important in order to prevent the development of bronchiectasis and deterioration in lung function. We report early diagnosis of PCD on nasal mucosal biopsy in two newborns who presented with prolonged respiratory distress and rhinorrhea.     

Dyskinésie ciliaire congénitale : qui et comment explorer ?

Primary ciliary dyskinesia (PCD) is a rare genetic disease associated with abnormal ciliary structure and function, which results in retention of mucus and bacteria in the respiratory tract, leading to chronic oto-sino-pulmonary disease from early childhood, situs abnormalities and abnormal sperm motility. The diagnosis of PCD can be difficult and is based on the presence of the characteristic clinical phenotype, evidence of abnormal ciliary function and specific ultrastructural ciliary defects identified by transmission electron microscopy. Because prognosis of the disease is related to the age of diagnosis, we suggest in this article, elements that should early orientate diagnostic evaluation of patients suspected of having PCD.     

Pierwotna dyskineza rzęsek – nowe możliwości diagnostyczne i aktualne zalecenia opieki nad pacjentem na przykładzie przypadku klinicznego

Primary ciliary dyskinesia (PCD) presents a diagnostic challenge. Coexistence of multiorgan abnormalities may facilitate the diagnosis. In this article, we present a case of a patient with a complex congenital heart disease and recurrent severe lower respiratory tract infections, in whom further diagnostics confirmed PCD with CCDC39 gene mutation. In recent years, genetic testing for PCD forms a valuable completion of the ciliary biopsy with electron microscopy. Once diagnosis of PCD is established, proper clinical care will have to be rendered to reduce the complications of the disease. In this article, the current recommendations for patient's clinical visits’ regimen, laboratory testing and suggested prophylactic methods are presented.     

Primary ciliary dyskinesia: age at diagnosis and symptom history

Age at diagnosis and the symptom history of children with primary ciliary dyskinesia (PCD) are described by reviewing the case notes in the paediatric PCD clinic. Mean age at diagnosis was 4.4 y despite a history of neonatal respiratory distress in 37/55 cases, situs inversus in 38/55 cases and early onset troublesome rhinitis in 42/55. Conclusion : Diagnosis of PCD is often delayed despite the presence of typical symptoms early in life. The key clinical features of unexplained neonatal respiratory distress, early onset rhinitis, situs inversus and a productive cough are highlighted, which, especially when occurring in combination, makes early referral for specific testing for PCD mandatory.     

Primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a genetic condition characterised by a variety of ciliary ultrastructural defects that result in cilia that are either stationary or beat in a dyskinetic fashion. Ineffective ciliary movement impairs mucociliary clearance resulting in mucus retention. This predisposes to recurrent chest infections, which may progress to bronchiectasis.PCD can present in infancy or late adulthood due to varying patterns of symptoms. Kartageners syndrome accounts for approximately 40% of patients. Late diagnosis is common despite symptoms of a daily moist cough and nasal discharge from the neonatal period.PCD is associated with a progressive decline in lung function associated with the development of widespread bronchiectasis. Early diagnosis followed by meticulous follow-up, antibiotic therapy and physiotherapy may halt this. With optimal treatment the prognosis is good. Diagnosis of PCD requires the evaluation of ciliary beat frequency, beat pattern and ultrastructural analysis of nasal ciliated epithelium. There are now three National Specialist commissioning Advisory Group (NSCAG)-funded centres established for the diagnosis of PCD.     

Cilia, primary ciliary dyskinesia and molecular genetics

Primary ciliary dyskinesia (PCD) is a phenotypically and genetically heterogeneous condition in which three genetic mutations have already been identified. The primary defect is in the ultrastructure or function of cilia, highly complex organelles that are structurally related to the flagella of sperm and protozoa. The clinical features of PCD include recurrent sinopulmonary infections, subfertility and laterality defects; the latter due to ciliary dysfunction at the embryological node. Completion of the human genome sequence has accelerated the identification and characterisation of disease genes, and the current molecular strategy in PCD includes candidate gene analysis, positional cloning, model organism analysis and proteomic analysis. The identification of these genes will provide new insights into the molecular mechanisms involved in the assembly and function of cilia and the pathway that determines left-right axis in man. This may also allow the development of new methods for diagnosis, prevention and treatment of PCD.     

Yield of bronchial forceps biopsies in addition to nasal brushing for ciliary function analyses in children

BACKGROUND: The diagnosis of primary ciliary dyskinesia (PCD) is unlikely, if ciliary beat frequency (CBF) is normal. The aim of this study was to test the diagnostic value of an additional bronchial biopsy in cases where nasal CBF are abnormal. PATIENTS, METHODS: In a paediatric bronchitis population nasal brush biopsies and bronchial forceps biopsies were taken. In both samples we measured CBF and compared results to nasal CBF of infants and children without respiratory disease. RESULTS: Patients with bronchitis (n = 31; 0.3 to 14.6 years; 10 girls) had a normal CBF in their nasal biopsies in 68 %, and in bronchial biopsies in 48 %, compared to the reference group (n = 72; 0.5 to 17.5 years; 23 girls). One patient had an abnormal nasal, but a normal bronchial ciliary activity. When cilia were beating at both sites (n = 14), nasal CBF agreed well with bronchial CBF (mean difference -0.78 Hz, 95 % confidence interval -1.81 Hz to 0.25 Hz). CONCLUSIONS: By adding the investigation of bronchial mucosa to the measurement of nasal CBF the diagnostic yield to exclude PCD was only improved from 68 % to 71 %. Consequently, if nasal ciliary activity is abnormal in infants and children with bronchitis, we do not recommend additional bronchoscopy to obtain another biopsy.     

Diagnostic approach to primary ciliary dyskinesia: a review

Primary ciliary dyskinesia (PCD) is a heterogeneous disease with impaired mucociliary transport leading to respiratory disorders, hearing impairment and male infertility. PCD can be diagnosed by clinical features together with functional and structural analysis of the cilia. To prevent bronchiectasis with a marked reduction in quality of life, early diagnosis is essential. The rarity of PCD and the costs of ultrastructural analysis of cilia require a rational diagnostic concept. We therefore reviewed the literature and compared clinical manifestations as well as functional and structural analyses of the cilia in 28 patients (23 children, 5 adults) investigated between 1990 and 1998. All were thoroughly examined for other possible diseases before biopsy, and ten patients (35.7%; eight children, two adults) were diagnosed as having PCD. From the literature review and our findings we conclude that ciliary investigation is indicated (a) in patients who remain suspected of having PCD despite thorough clinical examination and exclusion of other disorders such as cystic fibrosis, allergy, immunologic disorders and α₁-antitrypsin deficiency; (b) in patients with situs inversus suffering from chronic and/or recurrent airway infections; and (c) in patients with neonatal respiratory distress syndrome of “unknown” cause (i.e. after exclusion of hyaline membrane disease, aspiration syndromes, neonatal pneumonia, and pneumothorax as well as cardiovascular and metabolic diseases). Conclusion The combination of extensive clinical examination with functional and ultrastructural analysis of the cilia results in a high degree of accuracy in diagnosing PCD. Received: 30 November 1998 / Accepted: 20 July 1999     

Diagnostik der primären ziliären Dyskinesie

Characteristics

Primary ciliary dyskinesia (PCD) is a rare congenital disease of the cilia which is mostly manifested in the respiratory system.

Diagnostics

When there is a clinical suspicion of the presence of PCD and/or a positive screening result with reduced nasal nitrogen oxide (NO) values, further diagnostic measures should be initiated as soon as possible. In centers where high-frequency video microscopy analyses (HVMA) of beating of cilia are available, an initial nasal NO measurement for screening must not necessarily be carried out. As the first diagnostic measure for confirmation or exclusion of PCD, HVMA should be carried out. If the findings are conspicuous transmission electron microscopic analysis (TEM) of the ciliary structure and high-resolution immunofluorescence (IF) microscopic analysis of the cilia should follow. Mandatory for diagnosis are at least two congruent pathological findings from HVMA, TEM or IF. When a PCD variant with no evidence of ultrastructural defects is present, an identical pathological beating of cilia must be demonstrated with HVMA on three independent occasions. Following that a targeted genetic clarification should be attempted based on the findings for HVMA, TEM and IF. A clear genetic result can also confirm the diagnosis.

Approach

When PCD is suspected contact with a diagnostic center should be made. A reference center for PCD diagnostics will evaluate uncertain findings.     

Primary ciliary dyskinesia: Overlooked and undertreated in children

Primary ciliary dyskinesia (PCD) is a multi‐organ disorder associated with chronic oto‐sino‐pulmonary disease, neonatal respiratory distress, situs abnormalities and reduced fertility. Repeated respiratory tract infections leads to the almost universal development of bronchiectasis. These clinical manifestations are a consequence of poorly functioning motile cilia. However, confirming the diagnosis is quite difficult and is often delayed, so the true incidence of PCD may be significantly higher than current estimates. Nasal nitric oxide has been earmarked as a useful screening tool for identifying patients, but its use is limited in pre‐school‐aged children. Due to the rarity of PCD, the evidence base for management is somewhat limited, and treatment regimens are extrapolated from other suppurative lung disorders, like cystic fibrosis.     

Primary ciliary dyskinesia: Diagnosis in children with inconclusive ultrastructural evaluation

The purpose of this study was to distinguish between acquired and genetically determined ciliary abnormalities in children with severe chronic respiratory diseases. Samples of nasal ciliated epithelium from 50 subjects (25 male, 25 female; age-range 2–19 years) with severe chronic respiratory diseases were examined using transmission electron microscopy (TEM). Based on TEM findings, patients were divided into two groups: A and B. Group A comprised 39 children with ciliary alterations compatible with a condition probably occuring secondary to chronic inflammation (alterations of peripheral pairs, swollen cilia, and compound cilia). The other 11 patients, Group B, exhibited a greater number of alterations of the central pair and dynein arms (p< 0.001), which were qualitatively similar to, but less numerous than, those observed in primary ciliary dyskinesia (PCD). In both groups, analysis of ciliary beat frequency and waveform was performed by phase contrast microscopy (PCM). All the children with a ciliary beat frequency of < 7 Hz were treated with daily physiotherapy and with antibiotics, as recommended for PCD, for a 6-month period. After this treatment, the children were reexamined by PCM. Almost 50% of the children from Group B (i.e. those with a small proportion of specific ultrastructural defects) showed permanence of low ciliary beat frequency. This was also observed in two children of Group A. These children were considered to be affected by PCD. Our study describes a method for the diagnosis of PCD in the absence of specific ultrastructural defects or when these defects are present in only a small proportion of the cilia.     

原发性纤毛不动综合征诊断方法研究进展

原发性纤毛不动综合征是一种常染色体隐性遗传或X染色体相关的遗传疾病,国外发病率为1∶50 000~1∶10 000,国内尚无相关流行病学资料。该病发生机制为纤毛的双等位基因突变,导致组织器官的结构和/或功能改变,从而引起一系列相关临床表现,其中约50%为Kartagener综合征。目前常用的检查方法有鼻呼出气一氧化氮检测、透射电镜法、免疫荧光分析法、高频数字视频成像和基因诊断,但每种检查方法均有其优点及弊端。同时,统一的诊断思路及确切有效的治疗方案也处于探索研究阶段。     

Primary ciliary dyskinesia presentation in 60 children according to ciliary ultrastructure

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.     

Axonemal localization of the dynein component DNAH5 is not altered in secondary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a heterogeneous genetic disorder characterized by recurrent airway infections and situs inversus in half of affected individuals. Diagnosis currently relies on demonstration of abnormal ciliary ultrastructure or altered ciliary beat. Alterations encountered in secondary ciliary dyskinesia (SCD) caused by inflammation often complicate the diagnostic workup. We have recently shown that in respiratory epithelial cells from PCD patients with outer dynein arm defects the dynein protein DNAH5 is mislocalized and either completely or partially absent from the ciliary axoneme. In this study, we addressed the question whether SCD might affect axonemal DNAH5 localization in respiratory cells. To induce SCD in vitro, we treated primary human respiratory epithelial cell cultures with interleukin-13 (IL-13). Ciliary function and ultrastructure were assessed by high-speed videomicroscopy and transmission electron microscopy, respectively. For in vivo localization of DNAH5, we performed nasal brushing biopsies in patients with evidence of SCD. Expression of DNAH5 was analyzed by immunofluorescence microscopy. IL-13-treated cells showed evidence of SCD. Ciliary beat frequency was significantly reduced and ultrastructural analyses showed axonemal disorganization compared with control cells. High-resolution immunofluorescence studies of respiratory epithelial cells with SCD identified in vitro and in vivo normal axonemal DNAH5 localization. DNAH5 localization is not altered by SCD, indicating a high potential for immunofluorescence analysis as a novel diagnostic tool in PCD.     

Polycystic kidney disease: the cilium as a common pathway in cystogenesis

PURPOSE OF REVIEW: Polycystic kidney disease (PKD) is characterized by the formation and progressive expansion of cysts in the kidney, frequently leading to renal failure. The purpose of this review is to summarize recent studies that have provided insight into the mechanisms of cytogenesis. RECENT FINDINGS: Mutations in cilia-associated proteins have been identified in a number of diseases associated with cyst formation, including autosomal dominant and recessive PKD, and nephronophthisis. The primary cilia are finger-like projections on the surface of all kidney cells, except acid-base transporting intercalated cells in the collecting duct. Cilia have been proposed to serve as mechano- or chemosensors, responding to and interacting with the microenvironment. Abnormal cilia structure or function or both may lead to abnormalities in cell proliferation and tubular differentiation, ultimately leading to cyst formation. In addition to ciliary dysfunction, other potential mechanisms of cystogenesis need to be explored. SUMMARY: Our understanding of the importance of the primary cilium in renal cyst formation may guide potential therapy for cystic kidney diseases by targeting the structural and functional integrity of the cilia.     

Skeletal muscle metabolism in cystic fibrosis and primary ciliary dyskinesia

Previous studies have reported differences in muscle function and metabolism between patients with cystic fibrosis (CF) and healthy controls (HC), but it is currently unknown whether these abnormalities are specific to CF or also seen in other airway diseases. In this study, we used magnetic resonance spectroscopy (MRS) during exercise to assess muscle metabolism in CF patients. Twenty patients with CF and 20 age, gender, and habitual activity-matched HCs and a respiratory disease comparison group with primary ciliary dyskinesia (PCD; n = 10) were studied. Phosphorus MRS (P-MRS) was used to characterize muscle bioenergetic metabolism at rest and after high-, moderate-, and low-intensity exercise. CF patients exhibited lower resting ATP/phosphocreatine (PCr) ratio and significantly higher end-exercise pH values compared with both HC and PCD patients. Both CF and PCD patients demonstrated significantly slower PCr recovery time constants after high-intensity exercise. Our results suggest that not only there are specific abnormalities of muscle metabolism in CF patients but also there is a nonspecific impact of respiratory disease on muscle function.