Cystic Lung Changes, Bronchiectasis, and a Heterozygous-Primary Ciliary Dyskinesia-Associated Variant in the DNAH5 Gene: A Diagnostic Challenge.

BACKGROUND Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disease that can present at different ages with different phenotypes. Missed and delayed diagnoses are fairly common. Many variants in the DNAH5 gene have been described that confirm the diagnosis of PCD. Advances in medicine, especially in molecular genetics, have led to increasingly early discoveries of such cases, especially in those with nonclassical presentations. CASE REPORT This report describes a patient with bronchiectasis, lung cysts, finger clubbing, and failure to thrive who was misdiagnosed for several years as having asthma. Many differentials were suspected and worked up, including a suspicion of PCD. Genetic tests with whole-exome sequencing (WES) and whole-genome sequencing (WGS) detected a heterozygous, likely pathogenic, variant in the DNAH5 gene associated with PCD. CONCLUSIONS Despite a thorough workup done for this case, including a genetic workup, a PCD diagnosis was not established. We plan to reanalyze the WGS in the future, and with advent of technology and better coverage of genes, a genetic answer for this challenging case may resolve this diagnostic quandary in the future.

Device comparison study to measure nasal nitric oxide in relation to primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is a genetic respiratory disease characterized by chronic cough, recurrent respiratory infections, and rhinosinusitis. The measurement of nasal nitric oxide (nNO) against resistance has been suggested as a sensitive screening method. However, current recommendations argue for the use of expensive, chemiluminescence devices to measure nNO. This study aimed to compare nNO measurement using three different devices in distinguishing PCD patients from healthy controls and cystic fibrosis (CF) patients and to evaluate their diagnostic precision. The study included 16 controls, 16 PCD patients, and 12 CF patients matched for age and sex. nNO measurements were performed using a chemiluminescence device (Eco Medics CLD 88sp), and two devices based on electrochemical sensors (Medisoft FeNO+ and NIOX Vero) following standardized guidelines. Correlation estimation, Bland-Altman, ROC curve, and one-way ANOVA were used to assess device differences and diagnostic performance. Significantly lower nNO output values were observed in PCD and CF patients compared to controls during exhalation against resistance. The correlation analysis showed high agreement among the three devices. ROC curve analysis demonstrated 100% sensitivity and specificity at different cut-off values for all devices in distinguishing PCD patients from controls (optimal cut-offs: EcoMedics 73, Medisoft 92 and NIOX 87 (nl min-1)). Higher nNO output values were obtained with the Medisoft and NIOX devices as compared to the EcoMedics device, with a bias of-19 nl min-1(95% CI: -73-35) and -21 nl min-1(-73-31) accordingly. These findings indicate that all three tested devices can potentially serve as diagnostic tools for PCD if device specific cut-off values are used. This last-mentioned aspect warrants further studies and consideration in defining optimal cut-offs for individual device.

Siewert-Kartagener's syndrome in a dog.

Siewert-Kartagener's syndrome, a type of primary ciliary dyskinesia, is a complex disease comprising situs inversus, rhinosinusitis, and bronchiectasis. Situs inversus totalis is a condition in which all organs in the thoracic and abdominal cavities are reversed. Furthermore, primary ciliary dyskinesia, an autosomal genetic disease, may coexist with situs inversus totalis. Reports on Siewert-Kartagener's syndrome in veterinary medicine are limited. We report a rare case of primary ciliary dyskinesia with Siewert-Kartagener's syndrome in a dog, concurrently infected with canine distemper virus and type-2 adenovirus. This case highlights that situs inversus totalis can cause primary ciliary dyskinesia, and concurrent infections are possible.

Cross-sectional evaluation of the saccharin transit time test for primary ciliary dyskinesia: did we discard this tool too soon?

BACKGROUND: Primary ciliary dyskinesia (PCD) is a rare and heterogeneous disease that is difficult to diagnose and requires complex and expensive diagnostic tools. The saccharin transit time test is a simple and inexpensive tool that may assist in screening patients with PCD. OBJECTIVES: This study aimed to compare changes in the electron microscopy findings with clinical variables and saccharin tests in individuals diagnosed with clinical PCD (cPCD) and a control group. DESIGN AND SETTING: An observational cross-sectional study was conducted in an otorhinolaryngology outpatient clinic from August 2012 to April 2021. METHOD: Patients with cPCD underwent clinical screening questionnaires, nasal endoscopy, the saccharin transit time test, and nasal biopsy for transmission electron microscopy. RESULTS: Thirty-four patients with cPCD were evaluated. The most prevalent clinical comorbidities in the cPCD group were recurrent pneumonia, bronchiectasis, and chronic rhinosinusitis. Electron microscopy confirmed the clinical diagnosis of PCD in 16 of the 34 (47.1%) patients. CONCLUSION: The saccharin test could assist in screening patients with PCD due to its association with clinical alterations related to PCD.

Cystic fibrosis and primary ciliary dyskinesia: Similarities and differences.

Cystic fibrosis (CF) and Primary ciliary dyskinesia (PCD) are both rare chronic diseases, inherited disorders associated with multiple complications, namely respiratory complications, due to impaired mucociliary clearance that affect severely patients' lives. Although both are classified as rare diseases, PCD has a much lower prevalence than CF, particularly among Caucasians. As a result, CF is well studied, better recognized by clinicians, and with some therapeutic approaches already available. Whereas PCD is still largely unknown, and thus the approach is based on consensus guidelines, expert opinion, and extrapolation from the larger evidence base available for patients with CF. Both diseases have some clinical similarities but are very different, necessitating different treatment by specialists who are familiar with the complexities of each disease.This review aims to provide an overview of the knowledge about the two diseases with a focus on the similarities and differences between both in terms of disease mechanisms, common clinical manifestations, genetics and the most relevant therapeutic options. We hoped to raise clinical awareness about PCD, what it is, how it differs from CF, and how much information is still lacking. Furthermore, this review emphasises the fact that both diseases require ongoing research to find better treatments and, in particular for PCD, to fill the medical and scientific gaps.

Type II congenital pulmonary airway malformation with primary ciliary dyskinesia in a 4-year-old child: A case report.

A congenital pulmonary airway malformation (CPAM) combined with primary ciliary dyskinesia (PCD) has not been described in literature. Herein, we described the case of a 4-year-old boy who presented to us with recurrent productive cough and rhinorrhea for 2 years. High resolution computed tomography of the thorax revealed multiple, cystic, transparent shadows of different sizes near the posterior thoracic cavity in the lower lobe of the left lung. Thoracoscopic segmentectomy was carried out and histology confirmed a type II CPAM. Whole-exome sequencing revealed a compound heterozygous mutation (c.10568+1G>A, c.9484delG) in the DNAH11 gene associated with PCD that originated from the boy's mother and father, respectively. This report showed that when a child with CPAM presents with a productive cough and recurrent sinusitis, irrespective of situs inversus, PCD should be suspected. Genetic testing can aid in diagnosis.

[Sinusitis, otitis media and diffuse bronchiectasis in both lungs].

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive or X-linked biallelic mutations inherited disease, characterized by motile cilia dysfunction. Typical manifestations include bronchiectasis, secretory otitis media, sinusitis, situs inversus, and infertility. PCD often needs to be differentiated from cystic fibrosis (CF) because of similar clinical manifestations. In this paper, a juvenile female who presented with recurrent cough and expectoration with fever since early childhood, had a history of secretory otitis media and sinusitis, and had been considered for the diagnosis of CF. After the discovery of compound heterozygous mutations in PCD related pathogenic genes by gene sequencing, combined with the clinical manifestations and imaging characteristics, PCD was finally diagnosed.

Evaluation of ciliary functions and ciliary beat frequency via cell culture method in patients with primary ciliary dyskinesia.

BACKGROUND: Cell culture increases both diagnostic specificity and sensitivity of primary ciliary dyskinesia (PCD) and the most important reason to use cell culture for definitive diagnosis in PCD is to exclude secondary ciliary defects. Here we aimed to evaluate the cilia functions and cilia ultrastructural abnormalities after ciliogenesis of cell culture in patients with definitive diagnosis of PCD. We also aimed to compare high speed videomicroscopy (HSVM) results of patients before and after ciliogenesis and to compare them with electron microscopy, genetic and immunofluorescence results in patients with positive diagnosis of PCD. METHODS: This study was conducted as a cross-sectional study in patients with PCD. HSVM, transmission electron microscopy (TEM) and immunofluorescence staining results of the nasal biopsy samples taken from patients with the definitive diagnosis of PCD were evaluated and HSVM findings before and after cell culture were described. RESULTS: Ciliogenesis and regrowth in the cell culture occurred in the nasal biopsy sample of eight patients with PCD. The mean age of the patients was 15.5±4.2 years (8.5-18 years). Mean beat frequency was found to be 7.54±1.01 hz (6.53-9.45 hz) before cell culture, and 7.36±0.86 hz (6.02-7.99 hz) after cell culture in the nasal biopsy of patients. There was no significant difference in the beat frequency of PCD patients before and after cell culture. Ciliary function analysis showed the similar beating pattern before and after cell culture in patients with PCD. CONCLUSIONS: This study showed us that there was no difference between cilia beat frequency and beat pattern before and after cell culture in patients with definitive diagnosis of PCD and repeated HSVM would be a useful diagnostic approach in patients who have no possibility to reach other diagnostic methods.

Genome sequencing reveals underdiagnosis of primary ciliary dyskinesia in bronchiectasis.

BACKGROUND: Bronchiectasis can result from infectious, genetic, immunological and allergic causes. 60-80% of cases are idiopathic, but a well-recognised genetic cause is the motile ciliopathy, primary ciliary dyskinesia (PCD). Diagnosis of PCD has management implications including addressing comorbidities, implementing genetic and fertility counselling and future access to PCD-specific treatments. Diagnostic testing can be complex; however, PCD genetic testing is moving rapidly from research into clinical diagnostics and would confirm the cause of bronchiectasis. METHODS: This observational study used genetic data from severe bronchiectasis patients recruited to the UK 100,000 Genomes Project and patients referred for gene panel testing within a tertiary respiratory hospital. Patients referred for genetic testing due to clinical suspicion of PCD were excluded from both analyses. Data were accessed from the British Thoracic Society audit, to investigate whether motile ciliopathies are underdiagnosed in people with bronchiectasis in the UK. RESULTS: Pathogenic or likely pathogenic variants were identified in motile ciliopathy genes in 17 (12%) out of 142 individuals by whole-genome sequencing. Similarly, in a single centre with access to pathological diagnostic facilities, 5-10% of patients received a PCD diagnosis by gene panel, often linked to normal/inconclusive nasal nitric oxide and cilia functional test results. In 4898 audited patients with bronchiectasis, <2% were tested for PCD and <1% received genetic testing. CONCLUSIONS: PCD is underdiagnosed as a cause of bronchiectasis. Increased uptake of genetic testing may help to identify bronchiectasis due to motile ciliopathies and ensure appropriate management.

High-speed Video Microscopy Analysis for First-line Diagnosis of Primary Ciliary Dyskinesia.

Primary ciliary dyskinesia (PCD) is a congenital disorder predominantly inherited in an autosomal recessive trait. The disorder causes disturbance in the motion of cilia, leading to severe impairment of mucociliary clearance (MCC). If undiagnosed or diagnosed too late, the condition leads to the development of bronchiectasis and serious damage to the lungs in later life. Most of the methods for diagnosing PCD are time-consuming and demand extensive economic resources to establish them. High-speed video microscopy analysis (HSVMA) is the only diagnostic tool to visualize and analyze living respiratory cells with beating cilia in vitro. It is fast, cost-effective, and, in experienced hands, very reliable as a diagnostic tool for PCD. In addition, classical diagnostic measures such as transmission electron microscopy (TEM) are not applicable for some mutations as morphological changes are absent. This paper describes the process of collecting respiratory epithelial cells, the further preparation of the specimen, and the process of HSVMA. We also describe how brushed cells can be successfully kept unharmed and beating by keeping them in a nourishing medium for storage and transport to the investigation site in cases where a clinic does not possess the equipment to perform HSVMA. Also shown are videos with pathologic beating patterns from patients with a mutation in the dynein arm heavy chain 11 gene (DNAH11), which cannot be diagnosed with TEM; the result of an inconclusive HSVMA due to infection of the upper airways, as well as an unsuccessful brushing with superimposition of red blood cells. With this article, we would like to encourage every unit dealing with pulmonology patients and rare lung diseases to perform HSVMA as part of their daily routine diagnostics for PCD or send the specimens over to a center specializing in performing HSVMA.

Fissure adjacent partial lobe atelectasis in primary ciliary dyskinesia.

AIM: Establishing the underlying cause in a child with chronic suppurative lung disease (CSLD) allows for targeted treatment and screening for associated complications. One cause of CSLD is primary ciliary dyskinesia (PCD). Testing for PCD requires specialist expertise which is not widely available. Computed tomography (CT) scans are commonly performed when assessing CSLD. Identifying PCD-specific signs on CT would help clinicians in deciding when to refer for specialist testing. One potential PCD-specific sign we have observed is fissure adjacent partial lobe atelectasis (FAPLA). We aimed to assess if FAPLA is commonly found in CT of PCD patients. METHODS: Fifty-eight CT scans from 42 adult and child PCD patients were analysed. The presence and distribution of FAPLA were noted, and its association to sputum culture and other signs commonly seen in CSLD (bronchiectasis, bronchial wall thickening, air trapping and mucus plugging). RESULTS: FAPLA was found in 13 of 40 participants in their earliest CT scan. The prevalence of FAPLA was similar in children and adults. FAPLA involved the right middle lobe in all 13 cases and was systematically associated with ≥1 other structural change. There was no association between FAPLA and bacterial isolation from sputum. CONCLUSION: FAPLA was found in 32.5% PCD scans, without difference between children and adults in terms of frequency. Future work will determine if it is a PCD-specific sign by assessing whether it is also found in other CSLD processes and analysing more scans from children with PCD to determine how early this sign develops.

Kartagener's syndrome: a case report

Kartagener's syndrome is a subset of primary ciliary dyskinesia, an autosomal recessive inherited disease, and is characterized by the triad of chronic sinusitis, bronchiectasis, and situs inversus. This paper reports the case of a 27-year-old female presenting with dyspnea on medium exertion, accompanied by chronic cough, non-productive or with clear expectoration. She had recurrent pneumonia until 15 years of age and underwent a lobectomy in the lower lobe of the left lung, probably due to bronchiectasis. Chest computed tomography showed situs inversus totalis, signs of previous surgical manipulation, and mild bronchial thickening. Computed tomography of the paranasal sinuses showed signs of chronic sinusitis due to a probable ciliary kinesis disorder. These finding suggest the diagnosis of Kartagener's syndrome. The prognosis reveals a slow rate of decline in lung function. However, repeated or chronic infections can negatively influence the quality of life of these patients.

Case report of neurofibromatosis type 1 combined with primary ciliary dyskinesia.

Neurofibromatosis (NF) is a genetic disease in which the lungs are rarely involved. However, in NF cases with lung involvement, chest computed tomography may show bilateral basal reticulations, apical bullae, and cysts without bronchiectasis. Herein, we report a patient diagnosed with NF on the basis of the results of genetic testing who presented with early-onset wet cough and bronchiectasis. Considering the differential diagnosis of bronchiectasis combined with his early-onset wet cough, sinusitis, and sperm quality decline, we considered the possibility of primary ciliary dyskinesia (PCD). Further electron microscopy analysis of cilia and identification of homozygous mutations in the RSPH4A gene confirmed the diagnosis of PCD. Therefore, for patients with NF, when an image change exists in the lungs that does not correspond to NF, the possibility of other diagnoses, including PCD, must be considered.

The Primary Ciliary Dyskinesia Computed Tomography Score in Adults with Bronchiectasis: A Derivation und Validation Study.

BACKGROUND: Primary ciliary dyskinesia (PCD) is a rare genetic disorder which requires a complex diagnostic workup. Thus, an easy and widely available screening method would be helpful to identify patients who need a further diagnostic workup for PCD. OBJECTIVES: The aim of the study was to develop and validate a computed tomography (CT) score for PCD to facilitate etiological diagnosis in adults with bronchiectasis. METHOD: Chest CTs from 121 adults with bronchiectasis were scored for bronchiectasis morphology, distribution, and associated findings. Patients with and without the etiological diagnosis of PCD (46 and 75, respectively) were compared. Significantly, different imaging findings (p < 0.05) in univariate analysis were considered for multivariate analysis. Distinct findings were used to build the score. Based on this score, receiver operating characteristic (ROC) curve analysis was performed. The score was validated with 2 independent cohorts, another cohort from the same institution with 56 patients (28 with PCD) and an external cohort from another referral center with 172 patients (86 with PCD). RESULTS: The following parameters predicted PCD in adults with bronchiectasis and were included in the score with weighting according to their regression coefficients: 2 points were given for predominance in the middle/lower lobe, 2 points for tree-in-bud pattern, 2 points for atelectasis or prior resection of a middle/lower lobe, and 3 points for absence of emphysema and fibrosis. Situs inversus was only observed in subjects with PCD (Kartagener syndrome) and, thus, was not used in the primary ciliary dyskinesia computed tomography (PCD-CT) score as group comparisons could not be performed. ROC curve analysis revealed an area under the curve (AUC) of 0.90 (95% CI 0.85-0.96). Youden index was the highest at a threshold of >6 with a sensitivity of 83% and a specificity of 83%. In the validation cohorts, ROC curve analysis confirmed the performance of the score with an AUC of 0.83 (95% CI 0.72-0.94) in the first validation cohort and 0.79 (95% CI 0.73-0.86) in the external validation cohort. CONCLUSIONS: The PCD-CT score provides the first validated CT score for PCD and helps physicians in identifying adult bronchiectasis patients who require further diagnostic workup. Key message: The PCD-CT score provides the first validated CT score to assist physicians in identifying adult bronchiectasis patients who require a further diagnostic workup for PCD. It potentially improves earlier recognition of this rare and underdiagnosed disease.

Nasopharyngeal carcinoma in a child with Kartagener`s syndrome.

BACKGROUND: Kartagener`s syndrome, a subgroup of primary ciliary dyskinesia, is characterized by situs inversus totalis, chronic sinusitis and bronchiectasis. To date, the association of malignant diseases and Kartagener`s syndrome has been reported and all cases except angioimmunoblastic T cell lymphoma in a child have been seen in adulthood. CASE: A 10-year-old boy who was followed with the diagnosis of Katagener`s syndrome, presented with a progressive mass in the cervical region for 6 months. Physical examination revealed mental retardation, multiple lymphadenopathies, the largest in the left cervical region (4x4 cm), and pectus carinatum. Also, on cardiovascular examination, apex beat was felt on the right fifth intercostal space along midclavicular line. Magnetic resonance imaging of nasopharynx showed narrowing of the nasopharyngeal airway with an increase in wall thickness up to 2.5 cm on the posterior wall of the nasopharynx. Also, bilateral multiple cervical lymphadenopathies were noted. The pathological examination of the biopsy from cervical lymphadenopathy revealed a diagnosis of undifferentiated nasopharyngeal carcinoma. Chemotherapy was started for nasopharyngeal carcinoma chemotherapy regimen including cisplatin, docetaxel, and 5-fluorouracil. After four cycles of chemotherapy there was a significant regression in nasopharyngeal mass and lymphadenopathies. The patient underwent radiotherapy to the nasopharynx and bilaterally cervical regions. The patient has been in follow-up for 6 years well and tumor free. However, he is still under the supervision of the pediatric immunology and allergy departments due to recurrent respiratory infections and sinusitis. CONCLUSION: We present a case of nasopharyngeal carcinoma which developed in a child with Kartagener`s syndrome. To our knowledge, this is the first report of nasopharyngeal carcinoma in a child with Kartagener`s Syndrome.

[Management of Primary Ciliary Dyskinesia]. / Management der Primären Ciliären Dyskinesie.

Primary Ciliary Dyskinesia (PCD, MIM 242650) is a rare, hereditary multiorgan disease characterized by malfunction of motile cilia. Hallmark symptom is a chronic airway infection due to mucostasis leading to irreversible lung damage that may progress to respiratory failure. There is no cure for this genetic disease and evidence-based treatment is limited. Until recently, there were no randomized controlled trials performed in PCD, but this year, data of the first placebo-controlled trial on pharmacotherapy in PCD were published. This cornerstone in the management of PCD was decisive for reviewing currently used treatment strategies. This article is a consensus of patient representatives and clinicians, which are highly experienced in care of PCD-patients and provides an overview of the management of PCD. Treatments are mainly based on expert opinions, personal experiences, or are deduced from other lung diseases, notably cystic fibrosis (CF), COPD or bronchiectasis. Most strategies focus on routine airway clearance and treatment of recurrent respiratory tract infections. Non-respiratory symptoms are treated organ specific. To generate further evidence-based knowledge, other projects are under way, e. g. the International PCD-Registry. Participating in patient registries facilitates access to clinical and research studies and strengthens networks between centers. In addition, knowledge of genotype-specific course of the disease will offer the opportunity to further improve and individualize patient care.

PCD Detect: enhancing ciliary features through image averaging and classification.

Primary ciliary dyskinesia (PCD) is an inherited disorder of the motile cilia. Early accurate diagnosis is important to help prevent lung damage in childhood and to preserve lung function. Confirmation of a diagnosis traditionally relied on assessment of ciliary ultrastructure by transmission electron microscopy (TEM); however, >50 known PCD genes have made the identification of biallelic mutations a viable alternative to confirm diagnosis. TEM and genotyping lack sensitivity, and research to improve accuracy of both is required. TEM can be challenging when a subtle or partial ciliary defect is present or affected cilia structures are difficult to identify due to poor contrast. Here, we demonstrate software to enhance TEM ciliary images and reduce background by averaging ciliary features. This includes an option to classify features into groups based on their appearance, to generate multiple averages when a nonhomogeneous abnormality is present. We validated this software on images taken from subjects with well-characterized PCD caused by variants in the outer dynein arm (ODA) heavy chain gene DNAH5. Examining more difficult to diagnose cases, we detected 1) regionally restricted absence of the ODAs away from the ciliary base, in a subject carrying mutations in DNAH9; 2) loss of the typically poorly contrasted inner dynein arms; and 3) sporadic absence of part of the central pair complex in subjects carrying mutations in HYDIN, including one case with an unverified genetic diagnosis. We show that this easy-to-use software can assist in detailing relationships between genotype and ultrastructural phenotype, improving diagnosis of PCD.

Primary Ciliary Dyskinesia with Refractory Chronic Rhinosinusitis.

BACKGROUND Primary ciliary dyskinesia (PCD) is a rare genetic disease associated with abnormalities in the structure and function of cilia. The common clinical presentation of PCD is characterized by otitis media, chronic rhinosinusitis (CRS), chronic bronchitis, and infertility due to impaired ciliary motility. PCD is a complex disease and its diagnosis is complicated. However, there are some clinical features that are strong indicators of PCD, namely situs inversus, chronic otitis media, CRS, and chronic bronchitis with wet cough. CASE REPORT A 49-year-old male who had already received 3 operations for refractory CRS presented with nasal discharge, post nasal discharge, and chronic wet cough. Since childhood, he had suffered from otitis media, rhinosinusitis, and bronchitis. He also had a family history of CRS. He was diagnosed as having male infertility at another hospital, but the details were unknown. We performed a fourth surgery and obtained the nasal mucosa for electron microscope analysis during the operation. The transmission electron microscopic findings of the nasal cilia revealed several abnormalities in structure including a central complex defect, microtubular disorganization, and an inner dynein arm defect. Based on these findings and clinical courses, we made the definitive diagnosis of PCD. CONCLUSIONS When faced with refractory CRS cases with characteristic clinical symptoms that are associated with otitis media, chronic bronchitis, and infertility, clinicians should consider the possibility of PCD.

[Primary Ciliary Dyskinesia - Interdisciplinary Diagnostics and Therapy]. / Primäre Ziliendyskinesie (PCD) ­ interdisziplinäre Diagnostik und Therapie.

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disease. First respiratory symptoms already occur within the first hours after birth. Major symptoms are an unexplained neonatal respiratory distress syndrome, situs inversus, persistant cough, and chronic nasal congestion, recurrent paranasal sinus disorders with or without polyps, bronchiectasis as well as male infertility. Diagnostics is complex and includes transmission electron microscopy, nasal NO assessment, high-speed video microscopy and genetic evaluations. This review gives an overview over the current diagnostic procedures and therapeutic options. The management of PCD is a multidisciplinary approach, which should be reserved to in highly specialized centers.

Primary ciliary dyskinesia gene contribution in Tunisia: Identification of a major Mediterranean allele.

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disease of motile cilia. Even though PCD is widely studied, North-African patients have been rarely explored. In this study, we aim at confirming the clinical diagnosis and explore the genetic spectrum of PCD in a cohort of Tunisian patients. Forty clinically diagnosed patients with PCD belonging to 34 families were recruited from Tunisian pediatric departments. In each proband, targeted capture PCD panel sequencing of the 40 PCD genes was performed. PCD panel sequencing identified bi-allelic mutations in 82% of the families in eight PCD genes. Remarkably, 23.5% of patients carried the same c.2190del CCDC39 mutation. Single nucleotide polymorphism profiling in six unrelated patients carrying this mutation has revealed a founder effect in North-African patients. This mutation is estimated to date back at least 1,400-1,750 years ago. The identification of this major allele allowed us to suggest a cost-effective genetic diagnostic strategy in North-African patients with PCD.