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Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder affecting ciliary structure and function. PCD exhibiting dynein regulatory complex subunit 1 (DRC1) exon 1-4 deletion has been reported in several Japanese PCD patients; however, no large scale studies have been performed. Here, we aimed to determine the prevalence and founder effect of this variant in the Korean population. Using an in-house copy number variation tool, we screened for DRC1 exon 1-4 deletion in 20 patients with PCD and exome data of 1435 patients in the Seoul National University Hospital repository. In cases of suspected DRC1 deletion, confirmatory gap-PCR was performed. In a PCD cohort, three of 20 (15%) patients were positive for DRC1 exon 1-4 deletion (NM_145038.5(DRC1): c.1-3952_540 + 1331del27748-bp) while pathogenic variants were found in CCDC39 (N = 1), DNAAF6 (N = 1), DNAH9 (N = 1). In the 1,435-sample exome data, seven patients (0.49%) were confirmed to have DRC1 exon 1-4 deletion. A chimeric sequence including the junction was searched from the 1000 Genomes Project data repository. One Japanese patient (0.96%) was found to have the same DRC1 exon 1-4 deletion, which was absent in other populations. This study demonstrated that the DRC1 exon 1-4 deletion is a founder mutation based on haplotype analysis. In summary, the prevalence of PCD based on DRC1 exon 1-4 deletion is particularly high in Korean and Japanese populations, which is attributed to the founder effect. Genetic testing for DRC1 exon 1-4 deletion should be considered as an initial screening tool for Korean and Japanese patients with PCD., (© 2023. The Author(s), under exclusive licence to The Japan Society of Human Genetics.)

We aimed to determine a genetic diagnosis in the national primary ciliary dyskinesia (PCD) cohort of Cyprus, an island with a high disease prevalence. We used targeted next-generation sequencing (NGS) of 39 PCD genes in 48 patients of Greek-Cypriot and other ancestries. We achieved a molecular diagnosis in 74% of the unrelated families tested. We identified 24 different mutations in 11 genes, 12 of which are novel. Homozygosity was more common in Greek-Cypriot than non-Greek-Cypriot patients (88% vs. 46.2%, p = .016). Four mutations (DNAH11:c.5095-2A>G, CFAP300:c.95&#95;103delGCCGGCTCC, TTC25:c.716G>A, RSPH9:c.670+2T>C) were found in 74% of the diagnosed Greek-Cypriot families. Patients with RSPH9 mutations demonstrated higher nasal nitric oxide (57 vs. 15 nl/min, p <.001), higher forced expiratory volume in 1 s (-0.89 vs. -2.37, p = .018) and forced vital capacity (-1.00 vs. -2.16, p = .029) z scores than the rest of the cohort. Targeted multigene-panel NGS is an efficient tool for early diagnosis of PCD, providing insight into genetic disease epidemiology and improved patient stratification., (© 2021 Wiley Periodicals LLC.)

Background: Primary ciliary dyskinesia (PCD) is a heterogeneous disease with a diverse clinical and genetic spectrum among populations worldwide. Few cases of pediatric PCD have been reported from China., Research Question: What are the clinical and genotypic characteristics of children with PCD in China?, Study Design and Methods: Clinical characteristics, laboratory findings, and genetic results obtained for 75 patients with PCD were reviewed retrospectively at a single center in China. Genetic sequencing was conducted using whole-exome screening., Results: Patient median age at diagnosis was 7.0 years (range, 2 months-14 years). Of 75 patients, 88% (66/75) had chronic wet cough, 77% (58/75) had recurrent sinusitis, 76% (57/75) had bronchiectasis, 40% (30/75) had neonatal respiratory distress, and 28% (21/75) had coexistent asthma. Notably, postinfectious bronchiolitis obliterans (PIBO) as first presentation was found in 8% of children (6/75). Genes with the highest incidence of mutations were DNAH11 (15/51), followed by DNAH5 (9/51), CCDC39 (5/51), DNAH1 (4/51), and CCNO (3/51). Four genes (DNAI1, HEATR2, RSPH9, and DNAAF3) each were respectively found in two patients, and seven genes (CCDC40, LRRC6, SPAG1, RSPH4A, ARMC4, CCDC114, and DNAH14, a novel gene) each were mutated once. No differences in classical clinical features were observed among patients with commonly observed PCD-associated genotypes. However, three of six PIBO patients carried DNAH1 mutations., Interpretation: Besides typical clinical features, PIBO was observed as the first presentation of pediatric PCD in China. An association of the novel gene DNAH14 with PCD was observed, expanding the PCD genotypic spectrum., (Copyright © 2021 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Primary ciliary dyskinesia (PCD) is a rare genetic disorder of motile cilia dysfunction generally inherited as an autosomal recessive disease. Genetic testing is increasingly considered an early step in the PCD diagnostic workflow. We used targeted panel next-generation sequencing (NGS) for genetic screening of 33 Egyptian families with clinically highly suspected PCD. All variants prioritized were Sanger confirmed in the affected individuals and correctly segregated within the family. Targeted NGS yielded a high diagnostic output (70%) with biallelic mutations identified in known PCD genes. Mutations were identified in 13 genes overall, with CCDC40 and CCDC39 the most frequently mutated genes among Egyptian patients. Most identified mutations were predicted null effect variants (79%) and not reported before (85%). This study reveals that the genetic landscape of PCD among Egyptians is highly heterogeneous, indicating that a targeted NGS approach covering multiple genes will provide a superior diagnostic yield compared to Sanger sequencing for genetic diagnosis. The high diagnostic output achieved here highlights the potential of placing genetic testing early within the diagnostic workflow for PCD, in particular in developing countries where other diagnostic tests can be less available., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disease with low prevalence in pediatrics. Health studies have not sufficiently analyzed the role of psychological variables in rare diseases such as PCD. This paper studies the psychological characteristics of a group of pediatric patients diagnosed with PCD compared to their healthy peers. The sample consisted of 48 preadolescents-adolescents, aged 9-18 years (M = 12.96; SD = 2.71), with similar distribution by sex, and 25% of the patients having dyskinesia. Clinical anxiety-depression, self-esteem and psychological well-being were evaluated using questionnaires: the Adolescent Psychological Well-being Scale (BIEPS-J), the Hospital Anxiety and Depression Scale (HADS) and the Rosenberg Self-Esteem Scale (RSE). Data were analysed using descriptive, mean comparison (t-test) and diffuse comparative qualitative analysis (QCA). The results show no differences were found between healthy and PCD patients in the variables analyzed, except for social ties showing the latter greater well-being in this aspect. In QCA models, the variables that best explained the high or low levels of well-being were depression and self-esteem, and primary ciliary dyskinesia was not a necessary condition for presenting low levels of well-being. In conclusion, our results highlight the need to explore psychological aspects in pediatric patients with rare diseases., Competing Interests: The authors have declared that no competing interests exist.

Background: Mucociliary clearance is a main defense mechanism of the airway and is impaired in ciliary dyskinesia. The objective of this study was to evaluate the prevalence of chronic rhinosinusitis (CRS) and its characteristics in bronchiectasis patients suspected of harboring ciliary dyskinesia., Methods: Bronchiectasis patients referred to a rhinology clinic for nasal brush biopsy (NBB) were included in this study. NBB was performed using a curettage technique whereby ciliated epithelial cells were obtained from the surface of the inferior nasal turbinate. Results of transmission electron microscopy findings, primary ciliary dyskinesia (PCD) gene (35 genes) analyses (Invitae), and sinus computed tomography (CT) scans were reviewed., Results: Twenty-three patients (age, 54 ± 2.9 years) were referred for NBB between 2015 and 2018. Thirteen patients (56.5%) met the criteria for diagnosis of CRS. Nineteen patients had ciliary ultrastructural defects. The most common finding was compound cilia (n = 11, 47.8%). Five patients (21.7%) had central microtubule defects (CMD) with higher forced expiratory volume in 1 second (FEV 1 ) at the time of referral than those without CMD (CMD + , 91 ± 3.7%; CMD - , 73.5 ± 5.7%; p = 0.023). Of 15 subjects with a PCD gene panel, 67% (9 of 15) carried at least 1 gene associated with PCD. Only 1 patient reached diagnosis of PCD. Approximately 50% of non-PCD carriers had a smoking history (p < 0.05). Lund-Mackay scores did not significantly differ between PCD and non-PCD carriers (p = 0.72)., Conclusion: Nearly half of bronchiectasis patients referred for NBB had concurrent CRS. The presence of ciliary abnormalities was not amplified in bronchiectasis patients with CRS compared to those without CRS. Extrinsic factors may be related to ciliary structural abnormalities in non-PCD gene carriers., (© 2019 ARS-AAOA, LLC.)

Rationale: Having developed the first disease-specific, health-related quality of life (HRQoL) instruments for children with primary ciliary dyskinesia (PCD), we aimed to assess the psychometric performance of quality of life (QOL)-PCD child, adolescent, and parent-proxy versions in terms of reliability and validity across cross-cultural settings and caring for patients with this rare disease., Methods: Children (n = 71), adolescents (n = 85), and parents (n = 68) from multiple centers in the UK and North America completed age-appropriate QOL-PCD and generic QOL measures: pediatric QOL inventory, COPD assessment test (CAT), and Sino-Nasal Outcome Test 20. Total of 13 children, 13 parents, and 17 adolescents repeated QOL-PCD 10 to 14 days later to assess test-retest reliability. Multitrait analysis evaluated how the items loaded to hypothesized scales: physical, emotional & social functioning, treatment burden, role, vitality, upper and lower respiratory symptoms, and ears and hearing symptoms. Examination of item-to-total correlations led to removal of three, five, and six items, respectively in the prototype child, adolescent and parent-proxy versions; the validated measures now comprise between 34 and 38 items., Results: The QOL-PCD scales had good internal consistency; Cronbach's α for QOL-PCD parent-proxy ranged 0.62 to 0.86. Test-retest reliability demonstrated stability across all scales; for example QOL-PCD adolescent intraclass correlation coefficients ranged 0.71 to 0.89. Significant relationships were found between QOL-PCD scales and similar constructs on generic questionnaires, for example, QOL-PCD adolescent lower respiratory symptoms and the CAT score (r = .64, P < .01); weaker correlations were found between different constructs., Conclusion: Age-specific QOL-PCD demonstrated good internal consistency, test-retest reliability, and validity. QOL-PCD offers promising outcome measures for multicenter clinical trials, as well as monitoring symptoms, functioning, and QOL during routine care., (© 2019 Wiley Periodicals, Inc.)

Introduction: Caregiver burden impacts both the social and economic framework of society. Cystic fibrosis (CF) causes significant caregiver burden, but the current data is scarce. In the case of primary ciliary dyskinesia (PCD), even less is known. This study aims to compare the caregiver burden of the parents of patients with CF and PCD., Methods: Patients with CF and PCD between the ages of 6 to 13 and their parents were included. Patients' clinical information and parents' demographics were recorded. Caregiver burden was measured with Zarit Caregiver Burden Scale (ZCB), while the quality of life (QOL) was measured with CFQOL-revised (CFQOL-R) and PCD QOL questionnaire as the patients' age and diagnosis indicated., Results: A total of 63 patients, 44 with CF (69%) and 85 caregivers (35 mothers, 6 fathers, and 22 mother-father dyads) participated in the study. Caregiver burden was significantly higher in mothers of the CF group with a mean ZCB of 30.5 ± 10.7 when compared to the PCD group with a mean ZCB of 21.93 ± 8.26 (P = .006). This was similar in fathers with mean ZCB of 27.5 ± 9.21 in the CF group and 20.36 ± 7.43 in the PCD group (P = .03). In correlation analyses, mothers' caregiver burden moderately and inversely correlated with CFQOL-R subscales in the CF population., Conclusion: Caregiver burden is significantly higher in the CF population when compared to PCD. It is correlated with pulmonary functions and QOL in patients with CF., (© 2019 Wiley Periodicals, Inc.)

Introduction: Primary ciliary dyskinesia (PCD) is a rare, heterogeneous genetic disorder where impaired mucociliary clearance is caused by dysfunctional motile cilia leading to bronchiectasis. There is limited evidence characterising the nutritional status of children with PCD, although lower body mass index (BMI) z-score has been associated with worse lung function (FEV 1 )., Methods: All children (n = 43) with PCD, aged <16 years, from a single tertiary centre were prospectively enrolled. Information on clinical phenotype and nutritional status including bioelectrical impedance spectroscopy (BIS) phase-angle was collected., Results: There was a weak positive association between height-for-age z-score (HAZ) and FEV 1 z-score (n = 28, r = 0.4, p = 0.049). Those with a low fat free mass index (<-2 z scores) had a lower BMI z score (-1.3 ± 1.2 vs. 0.8 ± 0.7, p = 0.0002). BIS phase angle identified more patients at nutritional risk than using moderate malnutrition cut-offs of either HAZ or BMI ≤ -2 z scores alone (21% vs. 4.6% vs. 6.9% respectively). PCD patients had a higher incidence of vitamin D insufficiency (<50 nmoL/L) (54%) and deficiency (<30 nmoL/L) (26%) than healthy children., Conclusions: We have characterised the nutritional phenotype of a cohort of children with PCD. Monitoring vitamin D levels is important in PCD patients. There is a weak association between lung function and nutritional status, and measures of BIS phase-angle. The use of BIS phase-angle may allow for early identification of at risk children and may therefore be of benefit for nutritional assessments in the clinical setting. These findings will help inform a future nutritional intervention strategy in children with PCD., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Primary ciliary dyskinesia (PCD) is associated with abnormal organ positioning (situs) and congenital heart disease (CHD). This study investigated genotype-phenotype associations in PCD to facilitate risk predictions for cardiac and laterality defects. This retrospective cohort study of 389 UK patients with PCD found 51% had abnormal situs and 25% had CHD and/or laterality defects other than situs inversus totalis. Patients with biallelic mutations in a subset of nine PCD genes had normal situs. Patients with consanguineous parents had higher odds of situs abnormalities than patients with non-consanguineous parents. Patients with abnormal situs had higher odds of CHD and/or laterality defects., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Primary ciliary dyskinesia (PCD) and cri du chat syndrome (CdCS) are distinct disorders that can co-occur due to a common genetic locus on chromosome 5p. Chronic respiratory symptoms associated with PCD can occur in CdCS and are typically attributed to hypotonia, dysphagia, and aspiration. The prevalence of PCD among individuals with CdCS is not known., Methods: An online survey assessing common features of PCD was distributed to members of the 5P Minus Society, a cri du chat patient advocacy group. Respondents who met criteria for elevated risk of PCD (at least 3 symptoms or other features highly suggestive of PCD) were offered PCD genetic testing., Results: For the 123 respondents (median age 10.1 years with IQR 5.5-17.3 years; from 33 U.S. states and 10 other countries) chronic respiratory symptoms associated with PCD were prevalent, including unexplained neonatal respiratory distress, year-round nasal congestion beginning in infancy, and year-round, wet cough beginning in infancy in 35%, 32%, and 20% of respondents, respectively. Fifteen respondents (12%) met criteria for elevated risk for PCD and completed genetic analysis; however, none were diagnostic for PCD. A PCD clinical center evaluated an additional subject with CdCS who met criteria for likely PCD and had negative genetics, but had diagnostic electron microscopy of the respiratory cilia (missing outer dynein arms)., Conclusion: Clinicians should be aware of the genetic connection between CdCS and PCD. Non-informative genetic testing does not rule out PCD. CdCS patients with chronic respiratory symptoms may benefit from referral to specialized PCD diagnostic centers., (© 2018 Wiley Periodicals, Inc.)

Background: Hepatorenal fibrocystic diseases (HRFCDs) are a group of monogenic disorders characterized by developmental abnormalities involving the liver and kidney. In this study, we performed genotype and phenotype analyses of children with HRFCDs to determine the distribution of underlying diseases., Methods: A total of 36 children with HRFCDs were recruited, with genetic tests being performed in 22 patients and 14 patients diagnosed clinically as having autosomal recessive polycystic kidney disease (ARPKD)., Results: In children with HRFCDs, ARPKD was the most common disease, found in 16/36 (44.4 %), followed by nephronophthisis 13 (NPHP13) in 11/36 (30.6 %) and Meckel-Gruber syndrome type 3 (MKS3) in 4/36 (11.1 %). Renal function deteriorated faster in children with NPHP13. The main hepatic pathology was Caroli disease in the NPHP13 patients, while most other patients had Caroli syndrome or congenital hepatic fibrosis. Of note, three of four MKS3 patients had an accompanying choledochal cyst. No ARPKD patient had other organ involvement, while several NPHP13 patients had ocular and/or neurodevelopmental involvement. In contrast, all MKS3 patients had severe ocular and neurodevelopmental involvement., Conclusions: NPHP13 is a major disease in the HRFCD category, and thorough evaluation of its clinical features, including kidney, liver and other organ involvement, may aid in the differential diagnosis of HRFCD.

Meckel-Gruber (MKS) syndrome is a lethal autosomal abnormality diagnosed most commonly from classical findings on ultrasound scan after the late first trimester. There are few reports of cases followed up antenatally until delivery. We report here one of the largest series of 19 cases diagnosed antenatally from as early as 11 weeks gestation with 5 born alive. Of the 12 cases followed up antenatally, 7 were stillbirths while 5 were live births. The absence of obvious polycystic kidneys and severe oligohydramnios were prognostic features consistent with a live birth; however, mortality was 100% within a few weeks of delivery. The incidence of 2/1000 live births in the local population is similar to that reported from similar groups where consanguinity is more than 40%. The recurrence rate was high with 50% of the parous patients having had an affected baby. We conclude that diagnosis in early pregnancy does not require the classical triad of encephalocele, polydactyly and polycystic kidneys as some of these features do not manifest on imaging until much later.

Background: Meckel-Gruber syndrome (MKS) is a lethal rare inherited autosomal recessive disease. The syndrome is characterized by multiple congenital anomalies including polycystic kidneys, occipital encephalocele and polydactyly. The presence of two out of these anomalies is sufficient for a definitive diagnosis. At least 11 genes have been reported to-date to underlie MKS., Methods: In the current study we have retrospectively analyzed all the families at the Ha'Emek Medical Center in which the diagnosis of MKS was determined., Results: In total, 17 affected individuals are reported, originating from 12 sibships. The diagnoses were conducted or suspected by prenatal sonography, and some of the newborns were examined. Polycystic kidneys were present in 94% of cases, occipital encephalocele in 82% and polydactyly in about half of all cases. The underlying genetic cause was identified in 11 of our families, comprising mutations in 7 different genes, revealing high genetic heterogeneity., Conclusion: The identification of the genetic basis of MKS in our region allows focused and data-based genetic counseling and serves as an important tool for reproductive decisions, including the prevention of recurrence of pregnancies affected with this lethal syndrome. In the near future we plan to study the prevalence of the different MKS mutations found in each community in order to consider the expansion of national genetic screening in high risk populations.

Objectives/hypothesis: Although the migration of its squamous outer surface of the tympanic membrane has been well characterized, there is a paucity of data available concerning the migratory behavior of its medial mucosal surface. Existing theories of primary acquired cholesteatoma pathogenesis do not adequately explain the observed characteristics of the disease. We propose a new hypothesis, based upon a conjecture that mucosal membrane interactions are the driving force in cholesteatoma., Study Design: A retrospective chart review and a prospective observational cohort study in rats., Methods: After developing the new theory, it was tested through both clinical and experimental observations. To evaluate whether impairment of middle ear mucociliary migration would influence cholesteatoma formation, a retrospective chart review evaluating cholesteatoma occurrence in a sizable population of patients with either primary ciliary dyskinesia (PCD) or cystic fibrosis (CF) was performed. To study mucosal migration on the medial aspect of the tympanic membrane, ink tattoos were monitored over time in a rat model., Results: No cholesteatomas were identified in either PCD patients (470) or in CF patients (1,910). In the rat model, mucosa of the posterior pars tensa migrated toward the posterior superior quadrant, whereas the mucosa of the anterior pars tensa migrated radially toward the annulus., Conclusion: Mucosal coupling with traction generated by interaction of migrating opposing surfaces provides the first comprehensive theory that explains the observed characteristics of primary acquired cholesteatoma. The somewhat counterintuitive hypothesis that cholesteatoma is fundamentally a mucosal disease has numerous therapeutic implications., (© 2015 The American Laryngological, Rhinological and Otological Society, Inc.)

Meckel-Gruber Syndrome is a rare autosomal recessive lethal ciliopathy characterized by the triad of cystic renal dysplasia, occipital encephalocele and postaxial polydactyly. We present the largest population-based epidemiological study to date using data provided by the European Surveillance of Congenital Anomalies (EUROCAT) network. The study population consisted of 191 cases of MKS identified between January 1990 and December 2011 in 34 European registries. The mean prevalence was 2.6 per 100,000 births in a subset of registries with good ascertainment. The prevalence was stable over time, but regional differences were observed. There were 145 (75.9%) terminations of pregnancy after prenatal diagnosis, 13 (6.8%) fetal deaths, 33 (17.3%) live births. In addition to cystic kidneys (97.7%), encephalocele (83.8%) and polydactyly (87.3%), frequent features include other central nervous system anomalies (51.4%), fibrotic/cystic changes of the liver (65.5% of cases with post mortem examination) and orofacial clefts (31.8%). Various other anomalies were present in 64 (37%) patients. As nowadays most patients are detected very early in pregnancy when liver or kidney changes may not yet be developed or may be difficult to assess, none of the anomalies should be considered obligatory for the diagnosis. Most cases (90.2%) are diagnosed prenatally at 14.3 ± 2.6 (range 11-36) gestational weeks and pregnancies are mainly terminated, reducing the number of LB to one-fifth of the total prevalence rate. Early diagnosis is important for timely counseling of affected couples regarding the option of pregnancy termination and prenatal genetic testing in future pregnancies.

Background: Primary ciliary dyskinesia (PCD) is a rare disorder with variable disease progression. To date, mutations in more than 20 different genes have been found. At present, PCD subtypes are described according to the ultrastructural defect on transmission electron microscopy (TEM) of the motile cilia. PCD with normal ultrastructure (NU) is rarely reported because it requires additional testing. Biallelic mutations in DNAH11 have been described as one cause of PCD with NU.The aim of our study was to describe the clinical characteristics of a large population of patients with PCD, in relation to the ultrastructural defect. Additionally, we aimed to demonstrate the need for biopsy and cell culture to reliably diagnose PCD, especially the NU subtype., Methods: We retrospectively analyzed data from 206 patients with PCD. We compared the clinical characteristics, lung function, microbiology and imaging results of 68 patients with PCD and NU to those of 90 patients with dynein deficiencies and 41 patients with central pair abnormalities. In addition, we aimed to demonstrate the robustness of the diagnosis of the NU subtype in cell culture by data from genetic analysis., Results: PCD with NU comprised 33% (68/206) of all patients with PCD. Compared to other subtypes, patients with PCD and NU had a similar frequency of upper and lower respiratory tract problems, as well as similar lung function and imaging. With the currently widely applied approach, without cell culture, the diagnosis would have been missed in 16% (11/68) of patients with NU. Genetic analysis was performed in 29/68 patients with PCD and NU, and biallelic mutations were found in 79% (23/29) of tested patients., Conclusions: We reported on the clinical characteristics of a large population of patients with PCD and NU. We have shown that systematic performance of biopsy and cell culture increases sensitivity to detect PCD, especially the subtype with NU.PCD with NU has similar clinical characteristics as other PCD types and requires biopsy plus ciliogenesis in culture for optimal diagnostic yield.

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disease, caused by specific primary structural and/or functional abnormalities of the motile cilia. Prevalence, about 1/15,000 to 1/30,000, is probably underestimated, as diagnosis might not be evocated in absence of Kartagener syndrome. Diagnosis is confirmed in presence of abnormal ciliary motility as well as ciliary ultrastructure. Disease-causing mutations in at least 16 genes have already been identified; analysis will be guided by the type of ultrastructural abnormalities. An early and adequate diagnosis and therapy can theoretically improve the prognosis of the disease., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Human cilia were once thought merely to be important in respiratory mucociliary clearance, with primary ciliary dyskinesia (PCD) the sole manifestation of ciliary dysfunction. There are now known to be three types of cilia: primary, nodal and motile. Cilia are complex, likely involving more than 1000 gene products; in this review, recent advances in PCD genetics, and the potential relationships with genes causing other ciliopathies, are discussed. PCD is the most important respiratory disease, characterized by upper and lower airway infection and inflammation and disorders of laterality. Ciliary gene mutations are now known to cause single organ disease, as well as complex syndromes. The focus of the review is primarily PCD, in the context of the expanding ciliopathy spectrum. The authors consider the clinical situations in which ciliary disease should be considered, and the implications for specialist respiratory practice.

Background: Patients with congenital heart disease (CHD) and heterotaxy show high postsurgical morbidity/mortality, with some developing respiratory complications. Although this finding is often attributed to the CHD, airway clearance and left-right patterning both require motile cilia function. Thus, airway ciliary dysfunction (CD) similar to that of primary ciliary dyskinesia (PCD) may contribute to increased respiratory complications in heterotaxy patients., Methods and Results: We assessed 43 CHD patients with heterotaxy for airway CD. Videomicrocopy was used to examine ciliary motion in nasal tissue, and nasal nitric oxide (nNO) was measured; nNO level is typically low with PCD. Eighteen patients exhibited CD characterized by abnormal ciliary motion and nNO levels below or near the PCD cutoff values. Patients with CD aged >6 years show increased respiratory symptoms similar to those seen in PCD. Sequencing of all 14 known PCD genes in 13 heterotaxy patients with CD, 12 without CD, 10 PCD disease controls, and 13 healthy controls yielded 0.769, 0.417, 1.0, and 0.077 novel variants per patient, respectively. One heterotaxy patient with CD had the PCD causing DNAI1 founder mutation. Another with hyperkinetic ciliary beat had 2 mutations in DNAH11, the only PCD gene known to cause hyperkinetic beat. Among PCD patients, 2 had known PCD causing CCDC39 and CCDC40 mutations., Conclusions: Our studies show that CHD patients with heterotaxy have substantial risk for CD and increased respiratory disease. Heterotaxy patients with CD were enriched for mutations in PCD genes. Future studies are needed to assess the potential benefit of prescreening and prophylactically treating heterotaxy patients for CD.

Meckel-Gruber syndrome (MKS) is a severe autosomal recessively inherited disorder characterized by developmental defects of the central nervous system that comprise neural tube defects that most commonly present as occipital encephalocele. MKS is considered to be the most common syndromic form of neural tube defect. MKS is genetically heterogeneous with six known disease genes: MKS1, MKS2/TMEM216, MKS3/TMEM67, RPGRIP1L, CEP290, and CC2D2A with the encoded proteins all implicated in the correct function of primary cilia. Primary cilia are microtubule-based organelles that project from the apical surface of most epithelial cell types. Recent progress has implicated the involvement of cilia in the Wnt and Shh signaling pathways and has led to an understanding of their role in normal mammalian neurodevelopment. The aim of this review is to provide an overview of the molecular genetics of the human disorder, and to assess recent insights into the etiology and molecular cell biology of severe ciliopathies from mammalian animal models of MKS.

Congenital ciliary dysfunctions are recessively inherited disorders. The disorder is poorly recognized, if the patient has no situs inversus. The diagnosis is delayed, being made on the average at the age of over five years. The review deals with a recent European multinational survey of the occurrence, genetics, diagnostics and treatment of congenital ciliary dysfunctions. Data of Finnish pediatric patients under treatment have also been collected for the survey. The number of congenital ciliary dysfunctions found in Finland is approximately one fifth of that found in other Nordic countries.

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

Primary ciliary dyskinesia is an autosomal recessive multigenic disease that results in impaired mucociliary clearance. We have diagnosed 9 subjects with primary ciliary dyskinesia from geographically dispersed Amish communities, on the basis of clinical characteristics and ciliary ultrastructural defects. Despite consanguinity, affected individuals had evidence of genetic heterogeneity., (Copyright 2010 Mosby, Inc. All rights reserved.)

Rationale: Early diagnosis and treatment is considered important to prevent lung damage in primary ciliary dyskinesia (PCD)., Objectives: Few studies have addressed long-term evolution of lung function after PCD diagnosis. We investigated whether long-term lung function was dependent on age or level of lung function at PCD diagnosis., Methods: An observational, single-center, cross-sectional, and three-decade longitudinal study of FEV(1) and FVC related to age at diagnosis until current age was performed. Linear regression was used to describe the relation between first measured lung function values and age at diagnosis across the cohort. Courses of lung function after diagnosis and the according slopes were used to group patients into increasing, stable, or decreasing courses. Additionally, slopes from courses of 10 years of follow-up were related to age at diagnosis and initial level of lung function, respectively, using linear regression., Measurements and Main Results: Seventy-four children and adults with PCD were observed for median 9.5 (range, 1.5-30.2) years during which 2,937 lung function measurements were performed. First measured FEV(1) was less than 80% of predicted in one-third of preschool-diagnosed children. During observation, 34% of patients lost more than 10 percentage points, 57% were stable, and 10% improved more than 10 percentage points in FEV(1). Courses of lung function after diagnosis were related to neither age at diagnosis nor initial level., Conclusions: Our study strongly suggests that PCD is a disease of serious threat to lung function already at preschool age, and with a high degree of variation in courses of lung function after diagnosis that was not linked to either age or level of lung function at diagnosis. Early diagnosis did not protect against decline in lung function.

A transport function and motor activity of the ciliary system (MACS) of the nasal mucosa was studied in 10 patients with chronic polypous rhinosinusitis (CPRS). A complex examination included optic endoscopy of the nasal cavity for assessment of nasal polypous process, timing of the saccharine test (ST) according to standard technique, and ciliary beat rate (BR) by V.S. Kozlov method. For estimation of ciliary BR epithelium was taken from five zones: inferior and middle turbinated bones, nasal septum, base and top of the polyp growing from the median nasal passage. ST time in CPRS is much higher (28.3+/-0.34 min) than normal age-specific values. Ciliary BR in different nasal anatomic zones in CPRS is not similar. MACS on the inferior turbinated bone and nasal septum was absent, none of the samples contained cells with functioning cilia. Ciliary BR remained rather high, despite the pathological process, at the site of the top and base of the polyps as well as on the middle turbinated bone (8.7+/-1.07, 8.1+/-1.02, 6.5+/-0.35 Hz, respectively).

Immotile-cilia syndrome is characterized by severe respiratory distress from early infancy, and also often by situs inversus. The first description of the disease was based on just four persons, but reasons were given to suggest that the disorder may not be exceedingly rare. The purpose of the present study was to estimate just how rare or how common it is and to evaluate its association with situs inversus and with left-handedness. Data were mainly obtained from contacting a large number of Swedish clinicians who kindly informed us about their patients with suspected immotile-cilia syndrome. Diagnosis was in most cases performed by electron microscopical examination of nasal cilia or of spermatozoa. Based on these data, the prevalence of the syndrome in Sweden with or without situs inversus was estimated to be not far from 1 in 10,000. The syndrome consists of several subgroups that have a randomized determination of situs asymmetry (50% of these have situs inversus) and one subgroup in which situs inversus is not found. This results in a frequency of situs inversus in the syndrome of about 44 %. Left-handedness is no more common than it is in healthy persons and no more often associated with situs inversus than with situs solitus. In all cases it is about 14 %. It is concluded that the two major anatomical/physiological asymmetries of the human body are found with frequencies which indicate that they develop independently of each other. Both conditions appear with prevalences that may have changed at a centenary scale, left-handedness with a substantial increase and situs inversus with a less dramatic increase.

Studies on mucociliary clearance (MCC) in cystic fibrosis (CF) have produced conflicting results. This study aimed to differentiate primary (ion transport-related) from secondary (inflammatory) causes of delayed MCC in CF. Nasal MCC was measured in 50 children (CF, primary ciliary dyskinesia (PCD) and no respiratory disease). Nasal lavage fluid was analysed for interleukin (IL)-8 and tumour necrosis factor-alpha. Similar measurements were obtained in adult CF patients with and without chronic sinusitis (CS). Children with CF had neither delayed MCC nor increased levels of cytokines. Conversely, children with PCD had prolonged MCC times (all >30 min) and significantly raised levels of IL-8. CS-positive CF adults had significantly slower MCC than CS-negative subjects, but IL-8 levels were low and similar in both groups. Decreased airway surface liquid and delayed mucociliary clearance are the postulated primary mechanisms in cystic fibrosis. However, the current study reports that cystic fibrosis children have normal nasal mucociliary clearance. Abnormalities appeared in cystic fibrosis adults with symptoms of chronic sinus disease, suggesting a secondary rather than primary phenomenon. Studies to explore this mechanism in the distal, more sparsely-ciliated airways could aid an understanding of pathogenesis and the development of new treatments.

Unlabelled: 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.

Objective: To describe structural abnormalities of the respiratory cilia in newborn infants whose mothers consumed heroin during pregnancy., Patients and Methods: The medical records of 295 newborn infants whose mothers consumed heroin either throughout or at some time during pregnancy and who were cared for in Hospital del Mar in Barcelona (Spain) between January 1982 and December 1997 were reviewed. Seven infants with neonatal respiratory distress after the withdrawal syndrome period were selected. Diagnoses were established by electron microscopy of nasal mucosa samples., Results: All seven newborns with prolonged neonatal respiratory distress had ultrastructural abnormalities of the ciliary axoneme similar to those of primary ciliary dyskinesia or immotile cilia syndrome. The incidence of this alteration in this series was higher than that in the general population., Conclusions: These data suggest a possible association between ultrastructural abnormalities of the ciliary axoneme and prolonged neonatal respiratory distress in the infants of heroin-consuming mothers.

Patients with primary ciliary dyskinesia (PCD) have pronounced stasis of their respiratory secretions and therefore recurrent lower airway infections, which raises concerns for the development of lung function. Twenty four patients with PCD have been studied prospectively with a standardized regime in our clinic for 2-16 yrs with clinic visits, including spirometry 2-4 times per year, daily physiotherapy and monthly sputum cultures with subsequent specific antibiotic treatment. Lung function was significantly lower in the 12 PCD patients entering the cohort as adults when compared to the PCD patients entering as children (forced vital capacity (FVC) 70 versus 85% predicted; forced expiratory volume in one second (FEV1) 59 versus 72% pred). The lung damage did not relate to the type of ciliary dyskinesia. During the subsequent surveillance of the groups for a median of 14 and 7 yrs, respectively, the lung function remained stable in most patients. It is concluded that primary ciliary dyskinesia is accompanied by a progressive deterioration in lung function if undertreated, but lung function can be maintained with appropriate antibiotic treatment and regular physiotherapy. This emphasizes the need for early diagnosis of primary ciliary dyskinesia.

The prevalence of primary ciliary dyskinesia syndrome (PCDS) in Western countries is of 1/40,000 but is 13% in patients with bronchiectasis. The aim of this study was to determine the prevalence of PCDS in patients with bronchiectasis and sinusitis, including whether or not these patients present specific clinical signs. Eighteen patients with these two conditions from an area with 750,000 inhabitants in Valencia (Spain), were studied for 2 years. Radiologic and clinical information was recorded and mucociliary motility was measured with albumin marked with radioactive technetium. The structure of the nasal mucosa cilia was also studied. In 14 patients (77%) mucociliary motility was suppressed and in 13 ultrastructural changes typical of PCDS were observed. Only male infertility and situs inversus were more frequent in patients with PCDS; other clinical signs were equally severe and frequent in patients with PCDS and in those in whom no cause for bronchiectasis and sinusitis could be found. We conclude that 1) the prevalence of PCDS in patients with bronchiectasis and sinusitis is 77%; 2) in these patients a test of mucociliary motility is sufficient for diagnosis (structural study not being required); 3) the prevalence of PCDS in our population seems to be greater than that described; and 4) clinical signs are similar in patients with PCDS and in those with bronchiectasis of unknown genesis.

To evaluate the prevalence of inherited respiratory ciliary structure and underlying mucus abnormalities in the diffuse bronchiectasis syndrome, we investigated 53 subjects comprising 38 patients with diffuse bronchiectasis confirmed by high-resolution thoracic computed tomography, ten with chronic bronchitis and no diffuse bronchiectasis and five healthy nonsmoking control subjects. The clinical history was determined by means of a standardized questionnaire. Axonemal abnormalities of respiratory cilia were evaluated on bronchial or nasal mucosa samples by transmission electron microscopy (structure) and stroboscopic observation (function). Cystic fibrosis (CF) and Young's syndrome were detected by means of the sweat test and semen analysis when male infertility was suspected. Among the 38 patients with diffuse bronchiectasis, a primary ciliary dyskinesia (PCD) was detected in five (13%) with a high proportion (range: 55-100%) of cilia showing axonemal ultrastructural abnormalities always involving the dynein arms. The prevalence of this inherited condition was higher in North African (36%) than in European patients (4%) (p less than 0.01). After exclusion of the five patients with PCD, the patients with diffuse bronchiectasis showed axonemal ultrastructural abnormalities similar to those with chronic bronchitis. The diagnosis of underlying mucus disorders was based on two types of criterion, i.e. for CF, sweat chloride levels greater than 80 mmol.l-1, or the combination of diagnostic criteria proposed by Stern et al. Respectively, five (three Young's syndrome and two CF) and seven (one Young's syndrome and six CF) cases of inherited mucus disorders were suspected. Our results showed that PCD was highly prevalent among the adult North African patients with diffuse bronchiectasis but relatively rare in the Europeans.

We investigated the relationship between ciliary dyskinesia--commonly referred to as inmotile cilia syndrome--and sterility. In the past two years, we have accurately diagnosed 6 new cases of a total of 20 suspected as having this condition. To make the diagnosis, complete clinical, radiological, ultrastructural and spermatic work up was performed. All males in the fertile age were found to be sterile with spermatozoides with no motility. Sterility may initially go undetected in these patients due to early intense ORL and respiratory symptoms they present. However, mild forms of this disease entity may be asymptomatic and patients may consult for sterility with a clinical picture of scantily florid chronic bronchitis like that of smokers. Coincidental situs inversus may be useful in making the diagnosis.