Investigating genotype-phenotype correlations in primary ciliary dyskinesia: a sibling cohort study.

INTRODUCTION: Primary Ciliary Dyskinesia (PCD) is a complex mostly autosomal recessive disorder characterized by dysfunction of primary motor cilia, leading to multisystemic manifestations, primarily affecting the rhino-sinopulmonary system. Despite advancements in understanding its pathogenesis, genotype-phenotype correlations are not fully elucidated. Utilizing sibling cohorts offers a promising approach to investigate these genotype-phenotype correlations in PCD. MATERIALS AND METHODS: This retrospective cohort study, conducted from 2010 to 2023 at Soroka University Medical Center in Be'er-Sheva, Israel, included patients with a confirmed diagnosis of PCD. Variables and outcomes compared include typical presenting symptoms, lung function, structural changes in chest tomography (CT), and anthropometric data. RESULTS: Seventeen sibling patients from eight families met the inclusion criteria. At the last follow-up visit, the median age was 16 years. Genetic diagnosis revealed homozygous pathogenic variants including DNAH11, DNAAF3, DNAL1, and ZMYND10. Full concordance rates were observed for unexplained neonatal respiratory distress, chronic cough, and rhinosinusitis in patients with DNAH11 mutations. The family with the DNAAF3 mutation exhibited the lowest difference in Forced Expiratory Volume in 1 s (FEV1) Z-scores (0.48), but the highest differences in Forced Vital Capacity (FVC) Z-scores (3.39). High differences in FEV1 Z-scores were identified in the family with the DNAL1 mutation (2.06), while the lowest differences in FVC Z-scores (0.39) were observed in the same family. DISCUSSION: High concordance rates for certain mutations in clinical features suggest potential genotype-phenotype correlations, in contrast to weak concordance in lung function. Challenges remain in establishing direct correlations between genetic mutations and clinical outcomes.

Airway Clearance Techniques in Primary Ciliary Dyskinesia: A Systematic Review.

OBJECTIVE: Primary ciliary dyskinesia (PCD) is a respiratory disorder that impairs mucociliary clearance, leading to decreased lung function. Conventional chest physiotherapy (CCP) is the traditional airway clearance technique (ACT) and is considered a standard treatment for PCD patients. This systematic review investigated whether device supported ACTs are better alternatives for improving lung function and/or quality of life in PCD, compared with CCP. METHODS: The OVID Medline, PubMed, CINAHL, and Cochrane databases were searched. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed, and the Grading of Recommendations, Assessment, Development, and Evaluation approach was used to aggregate the data. This systematic review has been registered on the International Prospective Register of Systematic Reviews website. RESULTS: Of the 389 citations that resulted from our literature search, 2 randomized crossover trials that included a total of 54 patients were analyzed. The certainty of the aggregated study evidence was very low. No difference was identified between device-supported ACTs and CCP in terms of forced vital capacity and forced expiratory volume in 1 second in PCD patients aged 6 to 20 years. CONCLUSION: Device-supported ACTs could be considered alternative treatment options to replace CCP. High quality research is required to confirm this result.

Inhaled Medications for Maintenance Therapy in Pediatric Noncystic Fibrosis Bronchiectasis.

OBJECTIVE: This review focuses on evaluating literature for the use of inhaled mucolytics (hypertonic saline, mannitol, and dornase alfa), inhaled antibiotics (tobramycin, aztreonam, colistin, and amikacin), and inhaled corticosteroids in pediatric noncystic fibrosis bronchiectasis. DATA SOURCES: A literature search via PubMed was conducted using the search terms "non-cystic fibrosis bronchiectasis," "primary ciliary dyskinesia," and "bronchiectasis" in combination with each inhaled agent of interest. STUDY SELECTION AND DATA EXTRACTION: Studies were included if they were specific to patients with a clinical diagnosis of noncystic fibrosis bronchiectasis published from 1998 to July 2024. DATA SYNTHESIS: Several inhaled medications can be considered as maintenance therapies for pediatric patients with noncystic fibrosis bronchiectasis. Hypertonic saline could be considered for its potential airway clearance benefits and low risk of causing harm. Inhaled antipseudomonal antibiotics should be considered in patients who are colonized with Pseudomonas aeruginosa. Inhaled corticosteroid therapy should be reserved for patients with concomitant asthma. Dornase alfa has shown worse outcomes in adults with noncystic fibrosis bronchiectasis and should be used with caution. Risks and benefits should be carefully considered when evaluating these therapies for use in noncystic fibrosis bronchiectasis, and patient-specific treatment regimens should be developed. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Chronic management of pediatric noncystic fibrosis bronchiectasis remains challenging due to paucity of applicable literature. Risks and benefits of different agents are discussed in this article with recommendations for application to clinical practice based on studies performed in both adult and pediatric patients with noncystic fibrosis bronchiectasis. CONCLUSION: Several inhaled medications could be considered as maintenance therapies for pediatric patients with noncystic fibrosis bronchiectasis, with more robust evidence to support use of inhaled antipseudomonal antibiotics and hypertonic saline compared with other available agents. Further investigation is needed to identify a clear place in therapy for inhaled therapies in pediatric noncystic fibrosis bronchiectasis.

Lung ultrasound in children with primary ciliary dyskinesia or cystic fibrosis.

INTRODUCTION: Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are respiratory conditions requiring regular chest radiography (CXR) surveillance to monitor pulmonary disease. However, CXR is insensitive for lung disease in CF and PCD. Lung ultrasound (LU) is a radiation-free alternative showing good correlation with severity of lung disease in CF but has not been studied in PCD. METHOD: Standardized, six-zone LU studies and CXR were performed on a convenience sample of children with PCD or CF during a single visit when well. LU studies were graded using the LU scoring system, while CXR studies received a modified Chrispin-Norman score. Scores were correlated with clinical outcomes. RESULT: Data from 30 patients with PCD and 30 with CF (median age PCD 11.5 years, CF 9.1 years) with overall mild pulmonary disease (PCD median FEV1 90% predicted, CF FEV1 100%) were analyzed. LU abnormalities appear in 11/30 (36%) patients with PCD and 9/30 (30%) with CF. Sensitivity, specificity, positive predictive, and negative predictive values for abnormal LU compared to the gold standard of CXR are 42%, 61%, 42%, and 61% in PCD, and 44%, 81%, 50%, and 77% in CF, respectively. Correlation between LU and CXR scores are poor for both diseases (PCD r = -0.1288, p = 0.4977; CF r = 0.0343, p = 0.8571), and LU score does not correlate with clinical outcomes in PCD. CONCLUSION: The correlation of LU findings with CXR surveillance studies is poor in patients with mild disease burdens from PCD or CF, and LU scores do not correlate with clinical outcomes in PCD.

Characterization of pathogenic genetic variants in Russian patients with primary ciliary dyskinesia using gene panel sequencing and transcript analysis.

BACKGROUND: Primary ciliary dyskinesia (PCD) is a group of rare genetically heterogeneous disorders caused by defective cilia and flagella motility. The clinical phenotype of PCD patients commonly includes chronic oto-sino-pulmonary disease, infertility, and, in about half of cases, laterality defects due to randomization of left-right body asymmetry. To date, pathogenic variants in more than 50 genes responsible for motile cilia structure and assembly have been reported in such patients. While multiple population-specific mutations have been described in PCD cohorts from different countries, the data on genetic spectrum of PCD in Russian population are still extremely limited. RESULTS: The present study provides a comprehensive clinical and genetic characterization of 21 Russian families with PCD living in various country regions. Anomalies of ciliary beating in patients` respiratory epithelial cells were confirmed by high-speed video microscopy. In the most cases, custom-designed panel sequencing allowed to uncover causative variants in well-known or rarely mentioned PCD-related genes, including DNAH5, DNAH11, CFAP300, LRRC6, ZMYND10, CCDC103, HYDIN, ODAD4, DNAL1, and OFD1. The variations comprised common mutations, as well as novel genetic variants, some of which probably specific for Russian patients. Additional targeted analysis of mRNA transcripts from ciliated cells enabled us to specify functional effects of newly identified genetic variants in DNAH5 (c.2052+3G>T, c.3599-2A>G), HYDIN (c.10949-2A>G, c.1797C>G), and ZMYND10 (c.510+1G>C) on splicing process. In particular, the splice site variant c.2052+3G>T, detected in four unrelated families, resulted in skipping of exon 14 in DNAH5 transcripts and, according to haplotype analysis of affected probands, was proposed as an ancestral founder mutation in Udmurt population. CONCLUSIONS: The reported data provide a vital insight into genetic background of primary ciliary dyskinesia in the Russian population. The findings clearly illustrate the utility of gene panel sequencing coupled with transcriptional analysis in identification and clinical interpretation of novel genetic variants.

Impact of TAS2R38 polymorphisms on nasal nitric oxide and Pseudomonas infections in primary ciliary dyskinesia: relation to genotype.

OBJECTIVE: Primary ciliary dyskinesia (PCD) severity has been related to genotype and levels of nasal nitric oxide (nNO). The most common TAS2R38 haplotypes (PAV/PAV, PAV/AVI, AVI/AVI) encoding the bitter taste receptor can affect nNO levels and thus could play a role in the susceptibility to respiratory infections. We assessed the impact of these polymorphisms on nNO production and Pseudomonas aeruginosa (P.a.) infections in different PCD genotypes. METHODS: Prospective, longitudinal, single-centre study in patients with PCD with known genotype and one of three TAS2R38 haplotypes evaluated for up to 10 years. We related nNO values to TAS2R38 haplotypes in all patients, and in the three most frequent genotypes (CCDC39/CCDC40, DNAH5, DNAH11). In the genetic group(s) with different mean trends of nNO in relation to the polymorphism, we evaluated longitudinal lung function as a clinical outcome measure. We also studied any associations between the prevalence of chronic P.a. infection and PAV alleles. Linear mixed-effects models were used to evaluate longitudinal associations. RESULTS: 119 patients with PCD underwent 1116 study visits. Only in the DNAH11 mutations group was there a mean trend of nNO production which was significantly higher in PAV/PAV than AVI/AVI haplotype (p=0.033), with a better trend in spirometric and plethysmographic parameters. In patients with DNAH11 mutations the PAV allele was also associated with a significantly reduced prevalence of chronic P.a. CONCLUSION: TAS2R38 may be a modifier gene for PCD severity, but only in mild phenotype disease. Further study of TAS2R38 polymorphisms might enable new management strategies to prevent chronic P.a.

[The state of mucociliary transport of the mucous membrane of the inferior turbinates in children after various types of vasotomy]. / Sostoyanie mukotsiliarnogo transporta slizistoi obolochki nizhnikh nosovykh rakovin u detei posle razlichnykh vidov vazotomii.

The article presents the results of a study that included 127 children aged 8 to 17 years with a diagnosis of turbinate hypertrophy. The children are divided into three groups depending on the chosen vasotomy method. The methods of vasotomy were determined, after which there was a faster restoration of mucociliary clearance of the mucous membrane of the lower nasal concha.

TAS2R38 Genotype Does Not Affect SARS-CoV-2 Infection in Primary Ciliary Dyskinesia.

Several chronic respiratory diseases could be risk factors for acquiring SARS-CoV-2 infection: among them, Primary Ciliary Dyskinesia (PCD) is a rare (about 1:10.000) inherited ciliopathy (MIM 242650) characterized by recurrent upper and lower respiratory tract infections due to a dysfunction of the respiratory cilia. In this study, we aimed to investigate whether PCD subjects are more susceptible to infection by SARS-CoV-2 and whether some polymorphisms of the TAS2R38 bitter taste receptor correlate with an increased prevalence of SARS-CoV-2 infection and severity of symptoms. Patients answered several questions about possible SARS-CoV-2 infection, experienced symptoms, and vaccinations; in the case of infection, they also filled out a SNOT-22 questionnaire and ARTIQ. Forty PCD adult patients (mean age, 36.6 ± 16.7 years; 23 females, 17 males) participated in this study, out of which 30% had tested positive for COVID-19 during the last four years; most of them reported a mildly symptomatic disease. We found no differences in age or sex, but a statistically significant difference (p = 0.03) was observed in body mass index (BMI), which was higher in the COVID-acquired group (23.2 ± 3.3 vs. 20.1 ± 4.1 kg/m2). Genotyping for TAS2R38 polymorphisms showed a prevalence of 28.6% PAV/PAV, 48.6% PAV/AVI, and 22.8% AVI/AVI individuals in our cohort. In contrast to our hypothesis, we did not observe a protective role of the PAV allele towards SARS-CoV-2 infection. Conclusions: Our findings suggest that subjects with PCD may not be at increased risk of severe outcomes from COVID-19 and the TAS2R38 bitter taste receptor genotype does not affect SARS-CoV-2 infection.

Transcriptional regulation of CCNO during the formation of multiple motile cilia.

Primary ciliary dyskinesia (PCD) is a group of genetically heterogeneous disorders characterized by clinical manifestations resulting from abnormal ciliary motility. Mutations in critical genes, such as Cyclin O (CCNO), have been associated with severe respiratory disease, though limited data are currently available. Here we show that CCNO deficient ciliated cells can only form a reduced number of fully functional centrioles that can mature into ciliated basal bodies, and their transport and anchoring to the top of the plasma membrane are abnormal. Furthermore, we observed that CCNO localizes not only in the cytoplasm but also in the nucleus during the early stages of ciliogenesis, and this dual localization persists into adulthood. Transcriptome analysis revealed downregulation of genes involved in cilia assembly and movement, along with altered transcription factors associated with ciliation upon CCNO depletion. These findings indicate that CCNO may serve as a key regulator in the transcriptional regulation of multiciliogenesis.

Whole genome sequencing enhances molecular diagnosis of primary ciliary dyskinesia.

BACKGROUND: Primary ciliary dyskinesia (PCD) is a genetic disorder affecting motile cilia. Most cases are inherited recessively, due to variants in >50 genes that result in abnormal or absent motile cilia. This leads to chronic upper and lower airway disease, subfertility, and laterality defects. Given overlapping clinical features and genetic heterogeneity, diagnosis can be difficult and often occurs late. Of those tested an estimated 30% of genetically screened PCD patients still lack a molecular diagnosis. A molecular diagnosis allows for appropriate clinical management including prediction of phenotypic features correlated to genotype. Here, we aimed to identify how readily a genetic diagnosis could be made using whole genome sequencing (WGS) to facilitate identification of pathogenic variants in known genes as well as novel PCD candidate genes. METHODS: WGS was used to screen for pathogenic variants in eight patients with PCD. RESULTS: 7/8 cases had homozygous or biallelic variants in DNAH5, DNAAF4 or DNAH11 classified as pathogenic or likely pathogenic. Three identified variants were deletions, ranging from 3 to 13 kb, for which WGS identified precise breakpoints, permitting confirmation by Sanger sequencing. WGS yielded identification of a de novo variant in a novel PCD gene TUBB4B. CONCLUSION: Here, WGS uplifted genetic diagnosis of PCD by identifying structural variants and novel modes of inheritance in new candidate genes. WGS could be an important component of the PCD diagnostic toolkit, increasing molecular diagnostic yield from current (70%) levels, and enhancing our understanding of fundamental biology of motile cilia and variants in the noncoding genome.

Evaluation of Open-Source Ciliary Analysis Software in Primary Ciliary Dyskinesia: A Comparative Assessment.

Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder characterized by alterations in motile cilia function. The diagnosis of PCD is challenging due to the lack of standardized methods in clinical practice. High-speed video microscopy analysis (HSVA) directly evaluates ciliary beat frequency (CBF) in PCD. Recently, open-source ciliary analysis software applications have shown promise in measuring CBF accurately. However, there is limited knowledge about the performance of different software applications, creating a gap in understanding their comparative effectiveness in measuring CBF in PCD. We compared two open-source software applications, CiliarMove (v219) and Cilialyzer (v1.2.1-b3098cb), against the manual count method. We used high-speed videos of nasal ciliary brush samples from PCD RSPH4A-positive (PCD (RSPH4A)) patients and healthy controls. All three methods showed lower median CBF values for patients with PCD (RSPH4A) than in healthy controls. CiliarMove and Cilialyzer identified lower CBF in patients with PCD (RSPH4A), similarly to the manual count. Cilialyzer, CiliarMove, and manual count methods demonstrated statistical significance (p-value < 0.0001) in the difference of median CBF values between patients with PCD (RSPH4A) and healthy controls. Correlation coefficients between the manual count values against both software methods demonstrated positive linear relationships. These findings support the utility of open-source software-based analysis tools. Further studies are needed to validate these findings with other genetic variants and identify the optimal software for accurate CBF measurement in patients with PCD.

Infertility and pregnancy outcomes among adults with primary ciliary dyskinesia.

STUDY QUESTION: What is the prevalence of infertility and ectopic pregnancies among individuals with primary ciliary dyskinesia (PCD)? SUMMARY ANSWER: We found that 39 of 50 men (78%) and 72 of 118 women (61%) with PCD were infertile and that women with PCD had an increased risk of ectopic pregnancies (7.6 per 100 pregnancies, 95% CI 4.7-12.2). WHAT IS KNOWN ALREADY: PCD is a heterogeneous multiorgan disease caused by mutations in genes required for the function and structure of motile cilia. Previous studies identified a link between PCD and infertility, but original data on prevalence of infertility and risk of ectopic pregnancies, the use and efficacy of medically assisted reproduction (MAR), and the association of fertility with PCD genotype are extremely limited. STUDY DESIGN SIZE DURATION: We performed a cross-sectional survey about fertility within the Living with PCD study (formerly COVID-PCD). Living with PCD is an international, online, participatory study that collects information directly from people with PCD. People with PCD of any age from anywhere in the world can participate in the study. At the time of the survey, 482 adults with PCD were registered within the Living with PCD study. PARTICIPANTS/MATERIALS SETTING METHODS: We sent a questionnaire on fertility on 12 July 2022, to all participants older than 18 years enrolled in the Living with PCD study. Responses were collected until 8 March 2023. The fertility questionnaire covered topics related to pregnancy attempts, use of MAR, and pregnancy outcomes. Data were collected via the Research Electronic Data Capture (REDCap) platform. We defined infertility as failure to achieve a clinical pregnancy after 12 months or use of MAR for at least one pregnancy. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 265 of 482 adult participants (55%) completed the fertility questionnaire. Among 168 adults who had tried to conceive, 39 of 50 men (78%) and 72 of 118 women (61%) were infertile. Of the infertile men, 28 had tried MAR, and 17 of them (61%) fathered a child with the help of MAR. Among infertile women, 59 had used MAR, and 41 of them (69%) became pregnant with the help of MAR. In our population, women with PCD showed a relatively high risk of ectopic pregnancies: 1 in 10 women who became pregnant had at least one ectopic pregnancy and 7.6% of pregnancies were ectopic (95% CI 4.7-12.2). We evaluated the association between fertility and affected PCD genes in 46 individuals (11 men, 35 women) with available genetic and fertility information, and found differences between genotypes, e.g. all five women with a mutation in CCDC40 were infertile and all five with DNAH11 were fertile. LIMITATIONS REASONS FOR CAUTION: The study has limitations, including potential selection bias as people experiencing problems with fertility might be more likely to fill in the questionnaire, which may have influenced our prevalence estimates. We were unable to validate clinical data obtained from participant self-reports owing to the anonymous study design, which is likely to lead to recall bias. WIDER IMPLICATIONS OF THE FINDINGS: The study underlines the need for addressing infertility in routine PCD care, with a focus on informing individuals with PCD about their increased risk. It emphasizes the utility and efficacy of MAR in PCD-related infertility. Additionally, women attempting conception should be made aware of the increased risk of ectopic pregnancies and seek systematic early consultation to confirm an intrauterine pregnancy. Fertility, efficacy of MAR, and risk for adverse pregnancy outcomes differ between people with PCD-depending on genotypes-and close monitoring and support might be needed from fertility specialists to increase chances of successful conception. STUDY FUNDING/COMPETING INTERESTS: Our research was funded by the Swiss National Science Foundation, Switzerland (SNSF 320030B_192804), the Swiss Lung Association, Switzerland (2021-08_Pedersen), and we also received support from the PCD Foundation, USA; the Verein Kartagener Syndrom und Primäre Ciliäre Dyskinesie, Germany; the PCD Support UK, UK; and PCD Australia, Australia. M. Goutaki received funding from the Swiss National Science Foundation, Switzerland (PZ00P3_185923). B. Maitre participates in the RaDiCo-DCP funded by INSERM France. The study authors participate in the BEAT-PCD Clinical Research Collaboration supported by the European Respiratory Society. All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov ID NCT04602481.

Genetics of 67 patients of suspected primary ciliary dyskinesia from India.

Data are limited on the genetic profile of primary ciliary dyskinesia (PCD) from developing countries. Here, we report one of the first study on genetic profile of patients with suspected PCD from India. In this prospective cross-sectional study, we enrolled 162 children with suspected PCD. We recorded clinical features, relevant laboratory tests for PCD and performed whole exome sequencing (WES). We are reporting 67 patients here who had positive variant/s on WES. We had 117 variants in 40 genes among 67 patients. Among the 108 unique variants, 33 were categorized as pathogenic or likely pathogenic (P/LP). We had nine novel variants in out cohort. The 29 definite PCD cases, diagnosed by composite reference standards, had variants in 16 genes namely LRRC6/DNAAF11 (5), DNAH5 (3), CCDC39 (3), HYDIN (3), DNAH11 (2), CCDC40 (2), CCDC65 (2) and one each DNAAF3, DNAAF2, CFAP300, RPGR, CCDC103, CCDC114, SPAG1, DNAI1, and DNAH14. To conclude, we identified 108 unique variants in 40 genes among 67 patients. The common genes involved in definite cases of PCD in Indian patients were LRRC6, DNAH5, CCDC39, and HYDIN. Our findings suggest a need to develop a separate genetic panel for PCD in the Indian population.

Primary Ciliary Dyskinesia Due to Compound Heterozygous Variants in CFAP221 with Obstructive Azoospermia: Young's Syndrome May Be a Phenotype of Primary Ciliary Dyskinesia.

We report the case of a 42-year-old man with bronchiectasis who had a history of infertility treatment for obstructive azoospermia. Young's syndrome was suspected based on the triad of obstructive azoospermia, sinusitis, and bronchiectasis. He had normal electron microscopy findings, normal nasal nitric oxide levels (116 nL/min), and no situs inversus. However, we found compound heterozygous variants in CFAP221. This led to a diagnosis of primary ciliary dyskinesia (PCD). Distinguishing PCD from Young's syndrome in patients with the triad of obstructive azoospermia, sinusitis, and bronchiectasis is challenging. Young's syndrome may be a phenotype of PCD.

A novel splicing mutation DNAH5 c.13,338 + 5G > C is involved in the pathogenesis of primary ciliary dyskinesia in a family with primary familial brain calcification.

BACKGROUND: Primary ciliary dyskinesia (PCD) is an autosomal recessive hereditary disease characterized by recurrent respiratory infections. In clinical manifestations, DNAH5 (NM_001361.3) is one of the recessive pathogenic genes. Primary familial brain calcification (PFBC) is a neurodegenerative disease characterized by bilateral calcification in the basal ganglia and other brain regions. PFBC can be inherited in an autosomal dominant or recessive manner. A family with PCD caused by a DNAH5 compound heterozygous variant and PFBC caused by a MYORG homozygous variant was analyzed. METHODS: In this study, we recruited three generations of Han families with primary ciliary dyskinesia combined with primary familial brain calcification. Their clinical phenotype data were collected, next-generation sequencing was performed to screen suspected pathogenic mutations in the proband and segregation analysis of families was carried out by Sanger sequencing. The mutant and wild-type plasmids were constructed and transfected into HEK293T cells instantaneously, and splicing patterns were detected by Minigene splicing assay. The structure and function of mutations were analyzed by bioinformatics analysis. RESULTS: The clinical phenotypes of the proband (II10) and his sister (II8) were bronchiectasis, recurrent pulmonary infection, multiple symmetric calcifications of bilateral globus pallidus and cerebellar dentate nucleus, paranasal sinusitis in the whole group, and electron microscopy of bronchial mucosa showed that the ciliary axoneme was defective. There was also total visceral inversion in II10 but not in II8. A novel splice variant C.13,338 + 5G > C and a frameshift variant C.4314delT (p. Asn1438lysfs *10) were found in the DNAH5 gene in proband (II10) and II8. c.347_348dupCTGGCCTTCCGC homozygous insertion variation was found in the MYORG of the proband. The two pathogenic genes were co-segregated in the family. Minigene showed that DNAH5 c.13,338 + 5G > C has two abnormal splicing modes: One is that part of the intron bases where the mutation site located is translated, resulting in early translation termination of DNAH5; The other is the mutation resulting in the deletion of exon76. CONCLUSIONS: The newly identified DNAH5 splicing mutation c.13,338 + 5G > C is involved in the pathogenesis of PCD in the family, and forms a compound heterozygote with the pathogenic variant DNAH5 c.4314delT lead to the pathogenesis of PCD.

The relationship between lung function, exercise capacity, oxidant and antioxidant response in primary ciliary dyskinesia and cystic fibrosis.

BACKGROUND: There is a need to identify the complex interplay between various physiological mechanisms in primary ciliary dyskinesia (PCD) and cystic fibrosis (CF). The study investigated the interaction between respiratory function, exercise capacity, muscle strength, and inflammatory and oxidant/antioxidant responses in patients with PCD and CF. METHODS: The study included 30 PCD patients, 30 CF patients, and 29 age and sex-matched healthy subjects. Exercise capacity was assessed using the modified shuttle walk test (MSWT). Handgrip strength (HGS) was used to evaluate general muscle strength. Oxidative stress-inflammatory parameters were also assessed. Pulmonary function test was performed by spirometry. Regarding the forced expiratory volume in 1 second (FEV1) z-score, patients with PCD and CF were subdivided into normal, mild, and severe/moderate groups. RESULTS: Forced vital capacity (FVC) z-scores were lower in PCD and CF patients than controls. FEV1, FEV1/FVC, peak expiratory flow (PEF), and forced mid expiratory flow (FEF25-75%) z-scores were lower in PCD than in the other groups. HGS was lower in both mild PCD and normal CF patients relative to the controls. MSWT distance was lower in severe/moderate PCD patients than controls. Catalase (CAT), glutathione S-transferase (GST), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels did not differ significantly among the study groups, but superoxide dismutase (SOD) level in severe/moderate PCD, and glutathione (GSH) level in normal CF were higher than in controls. Interleukin-6 (IL-6) level was higher in patients with normal PCD and CF compared to the controls. IL-1ß level was higher in PCD compared to controls. Additionally, correlations among these parameters were also determined in some patient groups. CONCLUSION: Homeostasis related to respiratory function, aerobic performance, muscle strength, inflammatory response, and oxidant/antioxidant balance were affected in PCD and CF. Evaluating these mechanisms together may contribute to elucidating the pathophysiology of these rare diseases.

Prenatal genetic diagnosis of fetuses with dextrocardia using whole exome sequencing in a tertiary center.

To evaluate the genetic etiology of fetal dextrocardia, associated ultrasound anomalies, and perinatal outcomes, we investigated the utility of whole exome sequencing (WES) for prenatal diagnosis of dextrocardia. Fetuses with dextrocardia were prospectively collected between January 2016 and December 2022. Trio-WES was performed on fetuses with dextrocardia, following normal karyotyping and/or chromosomal microarray analysis (CMA) results. A total of 29 fetuses with dextrocardia were collected, including 27 (93.1%) diagnosed with situs inversus totalis and 2 (6.9%) with situs inversus partialis. Cardiac malformations were present in nine cases, extra-cardiac anomalies were found in seven cases, and both cardiac and extra-cardiac malformations were identified in one case. The fetal karyotypes and CMA results of 29 cases were normal. Of the 29 cases with dextrocardia, 15 underwent WES, and the other 14 cases refused. Of the 15 cases that underwent WES, clinically relevant variants were identified in 5/15 (33.3%) cases, including the diagnostic variants DNAH5, DNAH11, LRRC56, PEX10, and ZIC3, which were verified by Sanger sequencing. Of the 10 cases with non-diagnostic results via WES, eight (80%) chose to continue the pregnancies. Of the 29 fetuses with dextrocardia, 10 were terminated during pregnancy, and 19 were live born. Fetal dextrocardia is often accompanied by cardiac and extra-cardiac anomalies, and fetal dextrocardia accompanied by situs inversus is associated with a high risk of primary ciliary dyskinesia. Trio-WES is recommended following normal karyotyping and CMA results because it can improve the diagnostic utility of genetic variants of fetal dextrocardia, accurately predict fetal prognosis, and guide perinatal management and the reproductive decisions of affected families.

[Clinical and genetic characteristics of a case of primary ciliary dyskinesia caused by new frameshift mutation of the DNAH5 gene].

OBJECTIVE: To investigate the clinical and genetic characteristics of a case of primary ciliary dyskinesia (PCD). METHODS: We collected the clinical data on a case of PCD treated in the Department of Reproductive Medicine of Linyi People's Hospital in July 2020, detected the genes of the patient by whole-exome sequencing (WES), verified the candidate mutations by Sanger sequencing, and predicted the protein structure of the mutant gene by SWISS-MODEL. RESULTS: The proband was found with the clinical phenotypes of chronic rhinitis, bronchiectasis, visceral transposition and male infertility. WES revealed a homozygous frameshift variation of c.12890dup (p.N4297Kfs*13) in exon 74 of the DNAH5 gene, which led to the premature termination of polypeptide chain synthesis and affected the gene function. SWISS-MODEL prediction showed that some of the amino acid residues were deleted after mutation, resulting in a 3D conformational change of the protein. This variation was not recorded in the ClinVar, gnomAD and OMIM databases and, according to the relevant guidelines of the American College of Genetics and Genomics, was classified as a pathogenic variation (PVS1+PM2_P+PM3_P). CONCLUSION: The homozygous variation of the DNAH5 gene c.12890dup (p.N4297Kfs*13) may be the cause of the clinical phenotype of this case of PCD, and the above findings have enriched the variation spectrum of the DNAH5 gene.

A range of 30%-62% of functioning multiciliated airway cells is sufficient to maintain ciliary airway clearance.

BACKGROUND: Primary ciliary dyskinesia (PCD) is a genetic disorder caused by aberrant motile cilia function that results in defective ciliary airway clearance and subsequently to recurrent airway infections and bronchiectasis. QUESTION: How many functional multiciliated airway cells are sufficient to maintain ciliary airway clearance? METHODS: To answer this question we exploited the molecular defects of the X-linked recessive PCD variant caused by pathogenic variants in DNAAF6 (PIH1D3), characterized by immotile cilia in the affected males. We carefully analyzed the clinical phenotype, molecular defect (immunofluorescence and transmission-electron microscopy) and performed in vitro (particle tracking in air-liquid interface cultures) and in vivo (radiolabeled tracer studies) studies to assess ciliary clearance of respiratory cells from females with heterozygous and males with hemizygous pathogenic DNAAF6 variants. RESULTS: PCD males with hemizygous pathogenic DNAAF6 variants displayed exclusively immotile cilia, absence of ciliary clearance and severe PCD symptoms. Due to random or skewed X-chromosome inactivation in six females with heterozygous pathogenic DNAAF6 variants, 54.3%±10 (range 38%-70%) of multiciliated cells were defective. Nevertheless, in vitro and in vivo assessment of the ciliary airway clearance was normal or slightly abnormal. Consistently, heterozygous female individuals showed no or only mild respiratory symptoms. CONCLUSIONS: Our findings indicate that 30%-62% of functioning multiciliated respiratory cells are able to generate either normal or slightly reduced ciliary clearance. Because heterozygous females displayed either no or subtle respiratory symptoms, complete correction of 30% of cells by precision medicine might be able to improve ciliary airway clearance in PCD individuals as well as clinical symptoms.

Novel pathogenic variants of DNAH5 associated with clinical and genetic spectra of primary ciliary dyskinesia in an Arab population.

Introduction: Primary ciliary dyskinesia (PCD) is caused by the dysfunction of motile cilia resulting in insufficient mucociliary clearance of the lungs. This study aimed to map novel PCD variants and determine their pathogenicity in PCD patients in Kuwait. Methods: Herein, we present five PCD individuals belonging to a cohort of 105 PCD individuals recruited from different hospitals in Kuwait. Genomic DNAs from the family members were analysed to screen for pathogenic PCD variants. Transmission electron microscopy (TEM) and immunofluorescence (IF) analyses were performed on the nasal biopsies to detect specific structural abnormalities within the ciliated cells. Results: Genetic screening and functional analyses confirmed that the five PCD individuals carried novel pathogenic variants of DNAH5 causing PCD in three Arabic families. Of these, one multiplex family with two affected individuals showed two novel homozygous missense variants in DNAH5 causing PCD with situs inversus; another multiplex family with two affected individuals showed two newly identified compound heterozygous variants in DNAH5 causing PCD with situs solitus. In addition, novel heterozygous variants were identified in a child with PCD and situs solitus from a singleton family with unrelated parents. TEM analysis demonstrated the lack of outer dynein arms (ODAs) in all analysed samples, and IF analysis confirmed the absence of the dynein arm component of DNAH5 from the ciliary axoneme. Conclusion: The newly identified pathogenic variants of DNAH5 are associated with PCD as well as variable pulmonary clinical manifestations in Arabic families.