The challenges of diagnosing primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a rare genetic disorder of ciliary structure and function. The diagnosis can be challenging, particularly when using nongenetic assays. The "gold standard" diagnostic test is ultrastructural analysis of respiratory cilia obtained by nasal scrape or brush biopsy. A few specialized centers use high-speed videomicroscopy to examine ciliary beat. Certain beat patterns correlate with ultrastructural defects, and, in some cases, subtle alterations in beat pattern can be seen when ultrastructure is normal. Recent studies have shown that nasal nitric oxide (NO) is very low in patients with PCD compared with healthy control subjects; therefore, this assay may be a useful screening or adjunctive test for PCD. Because acute respiratory illnesses may yield alterations in ciliary ultrastructure, ciliary beat, and nasal NO values, these tests should be performed during a stable baseline period. Identification of an array of PCD genes has provided the opportunity for making a definitive genetic diagnosis for PCD in some cases. All of these approaches have a role in diagnosing PCD. For example, PCD has been confirmed by identifying disease-causing mutations in a heavy dynein chain gene in individuals with normal ciliary ultrastructure but subtle defects in ciliary beat and low nasal NO. Priorities to improve nongenetic diagnostic capability include standardization of nasal NO as a screening test and the development of specialized centers using uniform approaches for the analysis of ciliary ultrastructure and ciliary beat pattern. Another chapter in this issue (see Zariwala and colleagues, pp. 430) addresses the progress toward improved capabilities for definitive genetic testing.     

Primäre ziliäre Dyskinesie

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disorder with defective structure or function of normally motile cilia, leading to chronic upper and lower respiratory tract infections, fertility problems and organ site abnormalities. The PCD is a genetically heterogeneous condition entailing a broad range of different disease variants. Diagnosing these different PCD phenotypes requires a combined approach using complementary methods for detection of defects of ciliary function, ultrastructure and composition as well as low nasal nitric oxide values and biallelic genetic mutations. To date, mutations in 31 different genes have been linked to PCD permitting a genetic diagnosis in approximately 60?% of cases. Due to the lack of adequate trials evidence-based knowledge on the epidemiology, disease course and management of PCD is currently lacking. An international PCD registry has been developed to overcome these limitations (www.pcdregistry.eu) and is currently recruiting patients. Current treatment regimens have to rely on expert opinions and on experience gained from other respiratory diseases. The management of PCD includes surveillance of pulmonary function, culturing upper and lower airway secretions and diagnostic imaging. Daily airway clearance techniques as well as prompt antibiotic treatment of infections are the cornerstones of PCD treatment regimens.     

Genetic causes of bronchiectasis: primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder reflecting abnormalities in the structure and function of motile cilia and flagella, causing impairment of mucociliary clearance, left-right body asymmetry, and sperm motility. Clinical manifestations include respiratory distress in term neonates, recurrent otosinopulmonary infections, bronchiectasis, situs inversus and/or heterotaxy, and male infertility. Genetic discoveries are emerging from family-based linkage studies and from testing candidate genes. Mutations in 2 genes, DNAI1 and DNAH5, frequently cause PCD as an autosomal recessive disorder. A clinical genetic test has been recently established for DNAI1 and DNAH5, which involves sequencing 9 exons that harbor the most common mutations. This approach will identify at least one mutation in these 2 genes in approximately 25% of PCD patients. If biallelic mutations are identified, the test is diagnostic. If only one mutation is identified, the full gene may be sequenced to search for a trans-allelic mutation. As more disease-causing gene mutations are identified, broader genetic screening panels will further identify patients with PCD. Ongoing investigations are beginning to identify genetic mutations in novel clinical phenotypes for PCD, such as congenital heart disease and male infertility, and new associations are being established between 'ciliary' genetic mutations and clinical phenotypes.     

Gene Mutations in Primary Ciliary Dyskinesia Related to Otitis Media

Otitis media with effusion (OME) is the most common cause of conductive hearing loss in children and is strongly associated with primary ciliary dyskinesia (PCD). Approximately half of the children with PCD require otolaryngology care, posing a major problem in this population. Early diagnosis of PCD is critical in these patients to minimise the collateral damage related to OME. The current gold standard for PCD diagnosis requires determining ciliary structure defects by transmission electron microscopy (TEM) or clearly documenting ciliary dysfunction via digital high-speed video microscopy (DHSV). Although both techniques are useful for PCD diagnosis, they have limitations and need to be supported by new methodologies, including genetic analysis of genes related to PCD. In this article, we review classical and recently associated mutations related to ciliary alterations leading to PCD, which can be useful for early diagnosis of the disease and subsequent early management of OME.     

Diagnosis of primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a genetic disorder of ciliary structure or function. It results in mucus accumulation and bacterial colonization of the respiratory tract which leads to chronic upper and lower airway infections, organ laterality defects, and fertility problems. We review the respiratory signs and symptoms of PCD, as well as the screening tests for and diagnostic investigation of the disease, together with details related to ciliary function, ciliary ultrastructure, and genetic studies. In addition, we describe the difficulties in diagnosing PCD by means of transmission electron microscopy, as well as describing patient follow-up procedures.     

Analysis of the diagnosis of Japanese patients with primary ciliary dyskinesia using a conditional reprogramming culture

BackgroundPrimary ciliary dyskinesia (PCD) is diagnosed through multiple methods, including transmission electron microscopy (TEM), a high-speed video microscopy analysis (HSVA), immunofluorescence (IF), and genetic testing. A primary cell culture has been recommended to avoid the misdiagnosis of secondary ciliary dyskinesia derived from infection or inflammation and improve diagnostic accuracy. However, primary cells fail to differentiate into ciliated cells through repeated passages. The conditional reprogramming culture (CRC) method, a combination of a Rho-kinase inhibitor and fibroblast feeder cells, has been applied to cystic fibrosis. The goal of this study was to evaluate the value of CRC in diagnosing PCD in Japanese patients.MethodsEleven patients clinically suspected of having PCD were included. Airway epithelial cells were obtained from an endobronchial forceps biopsy and cultured at the air-liquid interface (ALI) combined with CRC. Ciliary movement, ultrastructure, and mutated ciliary protein evaluation were performed using HSVA, TEM, and IF, respectively. Genetic testing was performed on some patients.ResultsCRC yielded dense and well-differentiated ciliated cells with a high success rate (～90%). In patients with PCD, the ciliary ultrastructure phenotype (outer dynein arm defects or normal ultrastructure) and IF findings (absence of the mutated ciliary protein) were confirmed after CRC. In DNAH11-mutant cases with normal ultrastructure by TEM, the HSVA revealed stiff and hyperfrequent ciliary beating with low bending capacity in CRC-expanded cells, thereby supporting the diagnosis.ConclusionsCRC could be a potential tool for improving diagnostic accuracy and contributing to future clinical and basic research in PCD.     

Dyskinésie ciliaire primitive

Primary ciliary dyskinesia (PCD, MIM 242650) is an inherited respiratory disease caused by functional and ultrastructural abnormalities of respiratory cilia. This disorder, which affects 1 in 16,000 individuals, is usually transmitted as an autosomal recessive trait. In half the cases, PCD is associated with situs inversus (Kartagener syndrome). PCD is characterized by impaired mucociliary clearance resulting from a lack of ciliary motion, which is responsible for recurrent respiratory infections. The most frequent and first identified ciliary defect involves the dynein arms. The genetic heterogeneity underlying PCD is extremely important, and only three genes have as yet been identified in a few PCD patients with absence of outer dynein arms. The main clinical symptoms, at pulmonary and ENT levels, the abnormalities of ciliary structure and function, and the molecular basis of PCD will be reported in this review.     

Primary ciliary dyskinesia with CCDC39 variants displaying specific ciliary ultrastructure and movement concordant with the genotype: A case report

Primary ciliary dyskinesia (PCD) is a genetic disease with chronic airway infection and inflammation caused by ciliary ultrastructural defects and impairment in ciliary function.We present an adult case of PCD with compound heterozygous nonsense variants in CCDC39. The ciliary ultrastructure findings using electron microscopy and ciliary movement using high-speed video analysis matched the genotype. This is the first case report of PCD with CCDC39 variants in Japan demonstrating specific ciliary ultrastructure and movement related to the genotype.     

Primary ciliary dyskinesia: diagnostic and phenotypic features

Primary ciliary dyskinesia (PCD) is a genetic disease characterized by abnormalities in ciliary structure/function. We hypothesized that the major clinical and biologic phenotypic markers of the disease could be evaluated by studying a cohort of subjects suspected of having PCD. Of 110 subjects evaluated, PCD was diagnosed in 78 subjects using a combination of compatible clinical features coupled with tests of ciliary ultrastructure and function. Chronic rhinitis/sinusitis (n = 78; 100%), recurrent otitis media (n = 74; 95%), neonatal respiratory symptoms (n = 57; 73%), and situs inversus (n = 43; 55%) are strong phenotypic markers of the disease. Mucoid Pseudomonas aeruginosa (n = 12; 15%) and nontuberculous mycobacteria (n = 8; 10%) were present in older (> 30 years) patients with PCD. All subjects had defects in ciliary structure, 66% in the outer dynein arm. Nasal nitric oxide production was very low in PCD (nl/minute; 19 +/- 17 vs. 376 +/- 124 in normal control subjects). Rigorous clinical and ciliary phenotyping and measures of nasal nitric oxide are useful for the diagnosis of PCD. An increased awareness of the clinical presentation and diagnostic criteria for PCD will help lead to better diagnosis and care for this orphan disease.     

Implementación de un panel de genes para el diagnóstico genético de la discinesia ciliar primaria

IntroductionPrimary ciliary dyskinesia (PCD) is characterized by an alteration in the ciliary structure causing difficulty in the clearance of respiratory secretions. Diagnosis is complex and based on a combination of techniques. The objective of this study was to design a gene panel including all known causative genes, and to corroborate their diagnostic utility in a cohort of Spanish patients.MethodsThis was a multicenter cross-sectional study of patients with a high suspicion of PCD, according to European Respiratory Society criteria, designed around a gene panel for massive sequencing using SeqCap EZ capture technology that included 44 genes associated with PCD.ResultsWe included 79 patients, 53 of whom had a diagnosis of confirmed or highly probable PCD. The sensitivity of the gene panel was 81.1%, with a specificity of 100%. Candidate variants were found in some of the genes of the panel in 43 patients with PCD, 51.2% (22/43) of whom were homozygotes and 48.8% (21/43) compound heterozygotes. The most common causative genes were DNAH5 and CCDC39. We found 52 different variants, 36 of which were not previously described in the literature.ConclusionsThe design and implementation of a tailored gene panel produces a high yield in the genetic diagnosis of PCD. This panel provides a better understanding of the causative factors involved in these patients and lays down the groundwork for future therapeutic approaches.     

Diagnostik der primären ziliären Dyskinesie

Primary ciliary dyskinesia (PCD) is a phenotypically and genetically heterogeneous genetic disorder. The respiratory disease phenotype which is characterized by upper and lower airway infections results from inborn defects of respiratory cilia responsible for defective mucociliary clearance. Randomization of left/right body asymmetry is responsible for situs inversus (Kartagener’s syndrome) in half of affected individuals. As a screening test nasal nitric oxide measurement can be used. Establishment of the diagnosis currently relies on electron microscopy, high-resolution immunofluorescence analysis, and/or direct evaluation of ciliary beat by light microscopy. Recently mutations in the four genes DNAI1, DNAH5, TXNDC3, and DNAH11 that all encode for outer dynein arm proteins have been linked to recessive PCD. For diagnostic testing especially DNAH5 and DNAI1 mutation screening is useful, because they are responsible for more than 50% of PCD cases with outer dynein arm defects. Rarely mutations in RPGR (PCD + retinitis pigmentosa) and OFD1 (PCD + complex mental retardation syndrome) have been identified in X-linked recessive PCD variants.     

Primary ciliary dyskinesia syndrome associated with abnormal ciliary orientation in infants.

Primary ciliary dyskinesia (PCD) syndrome associated with abnormal ciliary orientation but with normal ciliary ultrastructure has been described in adults, but there are no normal ranges for orientation in infants, despite the fact that half of all patients with PCD present in the new-born period. Nasal brush biopsies were obtained from eight infants (three males), mean age 13.1 months, range 7-23, in order to determine ciliary orientation. They had no upper or lower airway disease and normal organ arrangement and were undergoing general anaesthesia for other reasons. Two infants with typical PCD syndrome but normal ultrastructure of individual cilia also had orientation studies. In the eight normal subjects, a mean of 254 central pairs was examined, range 82-453. The mean ciliary orientation was 14.9 degrees, range 12.9-17.5. The two infants with PCD syndrome but normal ultrastructure of individual cilia had ciliary orientation of (Case 1) 44.5 degrees (range 10.6-64.5) in 218 central pairs; and on a second occasion, 28.9 degrees, (range 9.0-47.5) in 259 central pairs; for Case 2, 24.4 degrees, (range 13.1-38.4) in 196 central pairs. The normal range for ciliary orientation is similar in infants to that described in other work in adults. The two cases of phenotypic primary ciliary dyskinesia in the presence of normal ciliary ultrastructure but abnormal ciliary orientation in infants supports the contention that measurement of ciliary orientation should be part of the assessment of ciliary structure and function in cases of possible primary ciliary dyskinesia, in particular when the ultrastructure of individual cilia appear to be normal.     

Primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is an inherited disorder characterized by impaired ciliary function that leads to an array of clinical manifestations including chronic bronchitis, chronic sinusitis, chronic otitis media, situs inversus (in approximately 50% of cases), and infertility. The underlying genetic and molecular defects have not been defined. Molecular genetic studies have demonstrated multiple gene loci. In a few families, defects in genes encoding ciliary dynein proteins have been identified. PCD is an interesting disease to compare with cystic fibrosis (CF) because both are airway diseases associated with impaired mucociliary clearance and with chronic infection of the airways leading to bronchiectasis as well as chronic infection of the sinuses that may be associated with nasal polyposis. The progression of the lower airway disease appears less rapid in PCD. Unlike CF, PCD is commonly associated with chronic otitis media, respiratory problems during the neonatal period, and situs inversus, suggesting that ciliary function is also important for clearing fluid/bacteria from the middle ear, for clearing fluid from the fetal lung during the transition to an air-filled neonatal lung, and for directing laterality of organs during embryonic development. The management for PCD lung disease is similar to that for CF and other diseases with chronic bronchitis leading to bronchiectasis.     

Primäre ziliare Dyskinesie

Primary ciliary dyskinesia (PCD) is an autosomal recessive disease characterized by abnormal ciliary motion and impaired mucociliary clearance. The prevalence of PCD is approximately 1:20,000 live births. Since cilia are common in many organs of the body, there is a wide variety of clinical manifestations in patients with PCD. Due to an extensive genetic heterogeneity the course of the disease varies largely, but with increasing age, the clinical symptoms are dominated by repeated respiratory infections and ultimately respiratory insufficiency. In the presence of situs inversus, which is observed in 50% of affected individuals, the diagnosis is easy, In cases of doubt, analyses of the kinetics and infrastructure of the cilia are necessary. The treatment of PCD is symptomatic. With optimal medical and physiotherapeutic management, the prognosis quoad vitam is good and life expectancy is nearly normal.     

原发性纤毛运动障碍1例及文献复习

目的 提高对原发性纤毛运动障碍(PCD)临床与病理特点的认识.方法 分析我院收治的1例PCD患者的临床资料及诊治经过,并复习相关文献.结果 患者临床表现为慢性咳嗽、咯痰、喘息;胸部CT表现为双肺弥漫的小结节改变并伴局部支气管扩张;经纤维支气管镜肺活检电镜病理表现为纤毛结构异常,动力臂缺失.其表现符合PCD.结论 PCD是由纤毛功能和(或)结构缺陷导致的一种常染色体隐性遗传病,容易误诊,其诊断依赖于纤毛超微结构检测.目前尚无标准治疗方案,以对症治疗为主.

Abstract：

Objective To improve the understanding of clinical and pathological characteristics of primary ciliary dyskinesia (PCD). Methods A case diagnosed with PCD was reported,and the related literatures were reviewed. Results The patient had cough,expectoration,and dyspnea. Chest CT scan showed diffuse nodules and local bronchieclasis. Transbronchial lung biopsy was done and transmission electron microscopy showed ciliary abnormalities and absence of dynein arms. Those findings were consistent with PCD. Conclusions PCD is an inherited disease characterised by functional and/or structural congenital abnormalities of cilia,and is often misdiagnosed. The diagnosis of PCD relies on the analysis of cilium ultrastructure. There is no specific therapy for PCD,and symptomatic treatment is recommended.     

原发性纤毛运动障碍1例及文献复习

目的 提高对原发性纤毛运动障碍(PCD)临床与病理特点的认识.方法 分析我院收治的1例PCD患者的临床资料及诊治经过,并复习相关文献.结果 患者临床表现为慢性咳嗽、咯痰、喘息;胸部CT表现为双肺弥漫的小结节改变并伴局部支气管扩张;经纤维支气管镜肺活检电镜病理表现为纤毛结构异常,动力臂缺失.其表现符合PCD.结论 PCD是由纤毛功能和(或)结构缺陷导致的一种常染色体隐性遗传病,容易误诊,其诊断依赖于纤毛超微结构检测.目前尚无标准治疗方案,以对症治疗为主.     

Diagnostic yield of nasal scrape biopsies in primary ciliary dyskinesia: A multicenter experience

Examination of ciliary ultrastructure remains the cornerstone diagnostic test for primary ciliary dyskinesia (PCD), a disease of abnormal ciliary structure and/or function. Obtaining a biopsy with sufficient interpretable cilia and producing quality transmission electron micrographs (TEM) is challenging. Methods for processing tissues for optimal preservation of axonemal structures are not standardized. This study describes our experience using a standard operating procedure (SOP) for collecting nasal scrape biopsies and processing TEMs in a centralized laboratory. We enrolled patients with suspected PCD at research sites of the Genetic Disorders of Mucociliary Clearance Consortium. Biopsies were performed according to a SOP whereby curettes were used to scrape the inferior surface of the inferior turbinate, with samples placed in fixative. Specimens were shipped to a central laboratory where TEMs were prepared and blindly reviewed. Four hundred forty‐eight specimens were obtained from 107 young children (0–5 years), 189 older children (5–18 years), and 152 adults (> 18 years), and 88% were adequate for formal interpretation. The proportion of adequate specimens was higher in adults than in children. Fifty percent of the adequate TEMs showed normal ciliary ultrastructure, 39% showed hallmark ultrastructural changes of PCD, and 11% had indeterminate findings. Among specimens without clearly normal ultrastructure, 72% had defects of the outer and/or inner dynein arms (IDA), while 7% had central apparatus defects with or without IDA defects. In summary, nasal scrape biopsies can be performed in the outpatient setting and yield interpretable samples, when performed by individuals with adequate training and experience according to an SOP. Pediatr. Pulmonol. 2011; 46:483–488. © 2011 Wiley‐Liss, Inc.     

Pulmonary radioaerosol mucociliary clearance in diagnosis of primary ciliary dyskinesia

BACKGROUND: Methods relying on nasal ciliary motility for the diagnosis of primary ciliary dyskinesia (PCD) are often hampered by secondary ciliary dyskinesia. A functional test for pulmonary mucociliary clearance, which is not influenced by secondary nasal ciliary defects, would be a valuable tool in a PCD workup. METHODS: The diagnostic validity and repeatability of a pulmonary radioaerosol mucociliary clearance (PRMC) test for the diagnosis of PCD was assessed in the following three sequentially performed substudies: (1) a preliminary cross-sectional study of PRMC in patients with known PCD; (2) a prospective blinded trial of patients referred for suspicion of PCD; and (3) an implementation study of PRMC as a routine method used in a PCD workup. PRMC was studied after (99m)Tc-albumin colloid aerosol inhalation, and the results were compared to (1) the results of nasal ciliary motility studies, (2) ciliary ultrastructure, and (3) the final clinical diagnosis. The repeatability of PRMC was assessed in 14 patients. RESULTS: A total of 95 patients, 5 to 74 years of age, were included in the study (57 patients in whom PCD was diagnosed, 26 non-PCD patients, and 12 patients referred for PCD workup without a conclusive workup result). In substudy 1, 14 of 15 patients with known PCD showed impaired PRMC; the results were inconclusive in 1 patient. In substudy 2, among 59 patients referred for PCD workup PRMC test results, compared to nasal ciliary motility, showed a sensitivity of 88% and a specificity of 100%. In substudy 3, among 21 patients referred for PCD investigation who were included in a routine PCD workup after PRMC implementation, 71% of PRMC test results were in alignment with nasal ciliary motility. Repeatability of interpretation was seen in 13 of 14 cases. A conclusive PRMC after only one test was found in 81 of 95 patients (85%). CONCLUSION: PRMC is a noninvasive functional test for total tracheobronchial mucociliary clearance with a high sensitivity and specificity for PCD, a high rate of conclusive results after only one test and a further ability to separate PCD from focal pulmonary mucociliary defects.     

Ultrastructural ciliary defects in children with recurrent infections of the lower respiratory tract

One hundred fifty-four children with recurrent or chronic infections of the lower respiratory tract compatible with the diagnosis of primary ciliary dyskinesia (PCD) were evaluated for the presence of ultrastructural ciliary abnormalities. Studies were performed on multiple samples of respiratory mucosa obtained by nasal and bronchial brushing. Twenty-eight children showed ultrastructural ciliary defects compatible with the diagnosis of PCD: Twenty-four presented dynein arm deficiency (either as isolated defect or in association with microtubular abnormalities), two had ciliary aplasia, and two showed microtubular abnormalities. Eleven patients with PCD had situs viscerum inversus, bronchiectasis, and chronic sinusitis (Kartagener's syndrome); one child with Kartagener's syndrome had normal ciliary structure. The appearance of respiratory symptoms within the first month of life, the colonization by Haemophilus influenzae, and a history of recurrent rhinitis and otitis were characteristically present in children with PCD. The clinical status of those patients who reached adolescence was, in our experience, remarkably good. An early diagnosis with adequate prevention and therapy of respiratory infections may have an important role in minimizing irreversible lung damage.     

CCDC40 mutation as a cause of infertility in a Chinese family with primary ciliary dyskinesia

Trial design:Primary ciliary dyskinesia (PCD) is a genetical disease that inherited in an autosomal-recessive way. Its clinical manifestations (such as male infertility) are mainly caused by defects of motion-related cilia that encoded by mutated genes. Although some mutation has been verified, a number of mutations of PCD remain elusive. The main purpose of this study is to identify mutant genes in a Chinese family with PCD, and to verify the safety and effectiveness of intracytoplasmic sperm injection (ICSI) of infertility caused by PCD.Methods:Imaging examination was used to exclude pulmonary inflammation and visceral translocation. Semen analysis was used to assess the quality of the proband''s sperm. Transmission electron microscopy (TEM) was conducted to assess the ultrastructure of flagella and cilia. Targeted next generation sequencing and Sanger sequencing and qPCR (real-time quantitative polymerase chain reaction detecting system) were applied to identified mutation of Chinese Family suspected of having PCD. Viable sperm were selected by hypo-osmotic swelling test (HOST) for ICSI.Results:We report 2 novel mutations in CCDC40 gene (c.1259delA and EX17_20 deletion) resulted in immobility of sperm and infertility of the proband. These mutations were confirmed in the proband''s sister (heterozygous) and his parents (recessive carrier) by Sanger sequencing and qPCR. All the spermatozoa from the proband were immotile. Ultrastructural defects were found in flagella and cilia of proband and his sister. Viable sperms were selected by HOST for ICSI and fertilized 9 of 21 eggs. Two frozen embryos were transplanted and a healthy 3500 g boy was delivered at 40 + 4 weeks’ gestation. And then, we summarized the genes related to PCD and the mutant sites of CCDC40 gene.Conclusion:We reported 2 novel mutants in CCDC40 gene (c.1259delA and EX17_20 deletion), which could be candidates for genetic diagnosis in PCD patients. The combination of targeted next generation sequencing and Sanger sequencing may be a useful tool to diagnose PCD. ICSI is a considerable method in treatment of infertility caused by PCD.