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.     

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     

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.     

Primary ciliary dyskinesia in children

OBJECTIVES: To point out primary ciliary dyskinesia as a cause of chronic respiratory disease in children.METHODS: A 10 year literature review on Medline and by direct research about the subject.RESULTS AND CONCLUSIONS: Primary ciliary dyskinesia is a disorder characterized by an abnormal mucociliary clearance. It affects both the upper and lower respiratory tracts and usually the clinical manifestations start in the first years of life. It can progress to bronchiectasis. Kartageners syndrome is the typical genetic manifestation. The diagnosis may be based on an abnormal saccharin test, but its confirmation depends on abnormal ultrastructure of the cilia or abnormal ciliary function. Many ciliary defects are currently known. The treatment is supportive, with measures to enhance mucociliary clearance, such as chest physiotherapy, prevention of infections by immunizations and prompt antibiotic therapy in the acute respiratory infections.     

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.     

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 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.     

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.     

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.     

Ciliary motility at light microscopy: a screening technique for ciliary defects?

To verify whether or not ciliary motility can be reliably assessed by light microscopy alone, we examined the nasal brushings of 53 patients with suspected ciliary dyskinesia and 10 healthy controls. The results of light microscopy were compared with cilia ultrastructure assessed with electron microscopy. Ciliary motility was significantly related with cilia ultrastructure. However, eight cases of lung disease due to bronchiectasis of unknown origin had immotile cilia on light microscopy, but normal ciliary ultrastructure on electron microscopy. Instances of normal and abnormal ultrastructure were detected in one case with motile cilia. There was an 83% agreement between electron microscopy and light microscopy. Sensitivity and specificity of light microscopy were 92% and 80%, respectively. In conclusion, light microscopy evaluation of ciliary motility does not appear to be a reliable screening test for ciliary dyskinesia because it does not quantify ciliary beat activity, which is a criterion for deranged ciliary motion. A complete evaluation of ciliary ultrastructure together with in vivo, if applicable, or in vitro function test (namely, the analysis of ciliary beat frequencies and/or waveform) is required for a definite diagnosis of ciliary dyskinesia.     

Primary ciliary dyskinesia. report of three cases

Primary ciliary dyskinesia is an autosomal recessive disorder, characterized by total or partial dysfunction of the ciliary or flagellated cells. It is clinically expressed by sinusitis and/or bronchiectasis occasionally associated with sterility in males. We report three cases of immotile cilia syndrome with chronic respiratory symptoms (sinusitis, bronchitis, otitis). The syndrome was associated with bronchiectasis in two cases and by half lobe atelectasis in the third. Diagnosis was established by ultrastructural study of samples from the nasal mucosa, in which the absence of the dynein arms and/or the anomalous disposition of the microtubules was observed. In all three patients great clinical improvement and symptom control were achieved, thereby improving the prognosis of these children. Although the syndrome cannot be cured, as in other chronic pneumopathies, early diagnosis and appropriate treatment can considerably reduce morbidity.     

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。     

Kartagener syndrome: An uncommon cause of neonatal respiratory distress?

We report a newborn with respiratory distress and situs inversus totalis. The diagnosis of primary ciliary dyskinesia was confirmed by both ultrastructural and functional investigations. The immotile cilia syndrome was suspected because of respiratory distress, situs inversus, abnormal nasal discharge and hyperinflated chest X-ray. We suggest that ultrastructural and functional investigations of the respiratory mucosa should be done in any newborn with respiratory distress without explanation for the respiratory problems. Establishment of the correct diagnosis at an early stage may allow to improve the prognosis provided prophylactic physiotherapy, vaccinations, and aggressive antibiotic treatment of intercurrent respiratory infections are instituted.Conclusion Despite its rarity, primany ciliary dyskinesia should be considered in unexplained cases of neonatal distress     

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.     

Clinical spectrum of primary ciliary dyskinesia in childhood

Although the triad of bronchiectasis, sinusitis and situs inversus was first described by Kartagener in 1933, the clinical spectrum of primary ciliary dyskinesia is still under investigation. Heterotaxy defects as well as upper and lower respiratory tract symptoms are the main manifestations in childhood. It is now recognized that situs inversus is encountered in only half of patients. The first lower respiratory symptoms may be present from infancy as neonatal respiratory distress. The most common lower airway manifestations are chronic wet cough, recurrent pneumonia and therapy resistant wheezing. Patients are at risk of developing bronchiectasis which may even be the presenting finding due to delayed diagnosis. Upper respiratory tract infections such as nasal congestion, nasal drainage and recurrent sinusitis as well as otologic manifestations such as otitis media or otorrhea with conductive hearing loss are also often encountered. It seems that the type of ciliary ultrastructure defects and the involved mutated genes are associated to some extent to the clinical profile. The disease, even in nowadays, is not recognized at an early age and the primary care clinician should have knowledge of its clinical spectrum in order to select appropriately the children who need further investigation for the diagnosis of this disorder.     

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.     

儿童原发性纤毛运动障碍的临床研究

目的 系统性研究儿童原发性纤毛运动障碍(primary ciliarydyskinesia,PCD)的临床特点,探讨PCD的诊断和鉴别诊断流程.方法 对PCD患儿的临床资料进行分析.结果 确诊PCD患儿26例,男11例,女15例.来自25个家族,1个家族诊断2例Kartagener综合征同胞姐弟.起病年龄为生后第2天～15岁,确诊时病程中位数为3.5年.所有患儿有咳嗽症状,24例有咯痰,7例有体格发育落后.23例接受支气管黏膜和(或)鼻黏膜的电镜检查,可见纤毛动力臂缺失6例,动力臂数目减少、微管排列紊乱、外周微管和(或)中央微管异常各4例,1例纤毛结构正常.经胸部CT证实,支气管扩张症8例,肺实变6例.20例存在鼻窦炎.15份痰或支气管肺泡灌洗液培养阳性标本中,铜绿假单胞菌8份,肺炎链球菌5份,白色念珠菌2份.其中1例培养出2种微生物.肺功能检查的16例中9例为阻塞性通气功能障碍.4例听力检测中3例异常,食管24 h pH值测定的5例患儿中3例有胃食管反流.结论 PCD起病年龄从新生儿期到青春期,呈慢性病程.主要临床表现为咳嗽、咯痰,可出现体格发育落后.PCD患儿中最多见的纤毛结构异常是动力臂缺失.部分患儿纤毛结构正常.影像学异常包括肺实变、支气管扩张症和鼻窦炎.常见的细菌病原为铜绿假单胞菌、肺炎链球菌,并可能存在混合感染.PCD患儿肺功能异常主要为阻塞性通气功能障碍,听力损害、胃食管反流出现率较高.     

Primary ciliary dyskinesia: what the general paediatrician needs to know

Primary ciliary dyskinesia is a multisystem disease with a range of phenotypes. Lung involvement is common, as abnormalities of cilial function lead to reduced airway clearance of mucus. Identifying children early is crucial in avoiding progression to bronchiectasis, and to allow timely support of growth and development. Key clinical features include a daily wet cough, neonatal chest symptoms, situs abnormalities, perennial rhinitis and chronic ear or hearing symptoms. These patients should be referred for specialist respiratory review and investigation. Investigations should begin with nasal nitric oxide and high speed video microscopy testing. Transmission electron microscopy and genetic testing may also be required. If results are initially negative this does not rule out PCD and further follow up and repeat investigation is recommended. Once PCD is confirmed a MDT approach is essential. This will include physiotherapy, aggressive antimicrobial therapy for exacerbations, regular immunisations, as well as other specialist input dependent on associated co-morbidities.     

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: 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.