The genetic framework of primary ciliary dyskinesia assessed by soft computing analysis.

BACKGROUND: International guidelines disagree on how best to diagnose primary ciliary dyskinesia (PCD), not least because many tests rely on pattern recognition. We hypothesized that quantitative distribution of ciliary ultrastructural and motion abnormalities would detect most frequent PCD-causing groups of genes by soft computing analysis. METHODS: Archived data on transmission electron microscopy and high-speed video analysis from 212 PCD patients were re-examined to quantitate distribution of ultrastructural (10 parameters) and functional ciliary features (4 beat pattern and 2 frequency parameters). The correlation between ultrastructural and motion features was evaluated by blinded clustering analysis of the first two principal components, obtained from ultrastructural variables for each patient. Soft computing was applied to ultrastructure to predict ciliary beat frequency (CBF) and motion patterns by a regression model. Another model classified the patients into the five most frequent PCD-causing gene groups, from their ultrastructure, CBF and beat patterns. RESULTS: The patients were subdivided into six clusters with similar values to homologous ultrastructural phenotype, motion patterns, and CBF, except for clusters 1 and 4, attributable to normal ultrastructure. The regression model confirmed the ability to predict functional ciliary features from ultrastructural parameters. The genetic classification model identified most of the different groups of genes, starting from all quantitative parameters. CONCLUSIONS: Applying soft computing methodologies to PCD diagnostic tests optimizes their value by moving from pattern recognition to quantification. The approach may also be useful to evaluate atypical PCD, and novel genetic abnormalities of unclear disease-producing potential in the future.

Stepwise genetic approach for the diagnosis of primary ciliary dyskinesia in highly consanguineous populations.

BACKGROUND: The American Thoracic Society guidelines for the diagnosis of primary ciliary dyskinesia (PCD) consider the presence of a bi-allelic pathogenic variant confirmatory for the diagnosis of PCD, with genetic testing recommended when other confirmatory diagnostic tests are less accessible. We present our experience with genetic testing as first line with a proposed algorithm for high consanguinity populations. METHODS: Patients with a suspected diagnosis of PCD underwent genetic testing according to a diagnostic algorithm composed of three steps: (1) patients with a previously known causative familial/Bedouin tribal pathogenic variant completed direct testing for a single variant; (2) if the initial test was negative or there was no known pathogenic variant, a PCD genetic panel was completed; (3) if the panel was negative, whole exome sequencing (WES) was completed. RESULTS: Since the implementation of the protocol, diagnosis was confirmed by genetic testing in 21 patients. The majority of them were of Bedouin origin (81%) and had a positive history of consanguinity (65%). Nine patients (43%) had a sibling with a confirmed diagnosis. Most patients (15/21, 71%) were diagnosed by direct pathogenic variant testing and the remainder by genetic panel (19%) and WES (10%). Disease-causing variants were found in nine genes, with DNAL1 (24%) and DNAAF3, DNAAF5, ZMYND10 (14% each) as the most prevalent ones. CONCLUSIONS: In highly consanguineous regions, a stepwise genetic testing approach is recommended. This approach may be particularly useful in areas where the ability to obtain confirmatory diagnostic tests through other modalities is less accessible.

Fertility care among people with primary ciliary dyskinesia.

INTRODUCTION: Fertility care is important for people living with primary ciliary dyskinesia (PCD) who are at increased risk of fertility problems. We investigated fertility care in an international participatory study. METHODS: Participants of the COVID-PCD study completed an online questionnaire addressing fertility issues. We used logistic regression to study factors associated with fertility specialist visits. RESULTS: Among 384 respondents (response rate 53%), 266 were adults (median age 44 years, interquartile range [IQR]: 33-54, 68% female), 16 adolescents, and 102 parents of children with PCD. Only half of adult participants (128; 48%) received care from fertility specialists at a median age of 30 years (IQR: 27-33)-a median of 10 years after PCD diagnosis. Only 12% were referred to fertility specialists by their PCD physician. Fertility specialist visits were reported more often by adults with pregnancy attempts (odds ratio [OR]: 9.1, 95% confidence interval [CI]: 3.8-23.6) and among people who reported fertility as important for them (OR: 5.9, 95% CI: 2.6-14.6) and less often by females (OR: 0.4, 95% CI: 0.2-0.8). Only 56% of participants who talked with healthcare professionals about fertility were satisfied with information they received. They expressed needs for more comprehensive fertility information and reported dissatisfaction with physician knowledge about PCD and fertility. CONCLUSION: People with PCD are inconsistently referred to fertility specialists. We recommend care from fertility specialists become standard in routine PCD care, and that PCD physicians provide initial fertility information either at diagnosis or no later than transition to adult care.

First preimplantation genetic testing case of Meckel syndrome with a novel homozygous TXNDC15 variant in a non-consanguineous Chinese family.

BACKGROUND: Meckel-Gruber syndrome (MKS) is a perinatally lethal, genetically heterogeneous, autosomal recessive condition caused by defective primary cilium formation. So far, the association of TXNDC15-related MKS has been reported in only five independent families from diverse ethnic origins, including Saudi, Pakistani, Estonian, and Indian. Here, we report a fetus diagnosed with MKS at 12 weeks, exhibiting typical ultrasound findings. METHODS: Low-coverage whole-genome sequencing was used to identify chromosomal abnormalities. Trio-base whole exome sequencing (trio-WES) was performed to investigate the potential pathogenic variants associated with MKS. Preimplantation genetic testing for monogenic disorders (PGT-M) was applied to prevent the transmission of the pathogenic variant. RESULTS: A novel homozygous pathogenic variant in the TXNDC15 gene was identified through trio-WES. The application of PGT-M successfully prevented the transmission of the pathogenic variant and resulted in an ongoing pregnancy. CONCLUSION: This is the first report of a TXNDC15 variant in the Chinese population and the first PGT case of TXNDC15-related MKS worldwide. The successful application of PGT-M in this family provides a potential approach for other monogenic diseases. Our case expands the variant spectrum of TXNDC15 and contributes to the molecular diagnosis and genetic counseling for MKS. This case underscores the importance of appropriate genetic testing methods and accurate genetic counseling in the diagnosis of rare monogenic diseases.

Pulmonary functions, nasal symptoms, and quality of life in patients with primary ciliary dyskinesia (PCD).

BACKGROUND: Several factors may influence quality of life (QOL) for patients with primary ciliary dyskinesia (PCD). We aimed to evaluate the association between pulmonary functions, nasal symptoms and QOL in PCD patients. METHODS: A prospective single center study. Patients performed spirometry, whole body plethysmography, forced oscillation technique (FOT), lung clearance index (LCI), 6-min walk test (6MWT), and filled two questionnaires: a specific PCD QOL questionnaire (PCD-QOL) and Sino-nasal outcome test (SNOT-22) questionnaire, assessing symptoms of chronic rhinosinusitis and health related QOL. RESULTS: Twenty-seven patients (56% females), age 19.4 ± 10.5 years were included; their, FEV1 was 74.6 ± 22.7%, and RV/TLC was (157.3 ± 39.3% predicted). Health perception and lower respiratory symptoms domains of PCD-QOL had the lowest score (median [IQR]: 50 [33.3-64.6] and 57.1 [38.9-72.2], respectively). FOT parameters correlated with several PCD-QOL domains. R5 z-score (indicating total airway resistance) and AX z-score (indicating airway reactance) correlated negatively with physical domain (r = -0.598, p = .001, and r = -0.42, p = .03, respectively); R5 z-score also correlated negatively with hearing domain (r = -0.57, p = .002). R5-20 z-score (indicating small airway resistance) correlated negatively with role domain (r = -0.49, p = .03). SNOT-22 score correlated negatively with several PCD-QOL domains (lower respiratory symptoms r = -0.77, p < .001; physical r = -0.72, p < .001; upper respiratory symptoms r = -0.66, p < .001). No correlations were found between spirometry values, LCI, 6MWT, and PCD-QOL. CONCLUSIONS: FOT suggested small airway dysfunction, and correlated negatively with several PCD-QOL domains. Nasal symptoms had strong negative correlations with PCD-QOL. Larger longitudinal studies will further elucidate factors affecting QOL in PCD.

Diagnosis of Primary Ciliary Dyskinesia via Whole Exome Sequencing and Histologic Findings.

PURPOSE: To assess the diagnostic potential of whole-exome sequencing (WES) and elucidate the clinical and genetic characteristics of primary ciliary dyskinesia (PCD) in the Korean population. MATERIALS AND METHODS: Forty-seven patients clinically suspected of having PCD were enrolled at a tertiary medical center. WES was performed in all patients, and seven patients received biopsy of cilia and transmission electron microscopy (TEM). RESULTS: Overall, PCD was diagnosed in 10 (21.3%) patients: eight by WES (8/47, 17%), four by TEM. Among patients diagnosed as PCD based on TEM results, two patients showed consistent results with WES and TEM of PCD (2/4, 50%). In addition, five patients, who were not included in the final PCD diagnosis group, had variants of unknown significance in PCD-related genes (5/47, 10.6%). The most frequent pathogenic (P)/likely pathogenic (LP) variants were detected in DNAH11 (n=4, 21.1%), DRC1 (n=4, 21.1%), and DNAH5 (n=4, 21.1%). Among the detected 17 P/LP variants in PCD-related genes in this study, 8 (47.1%) were identified as novel variants. Regarding the genotype-phenotype correlation in this study, the authors experienced severe PCD cases caused by the LP/P variants in MCIDAS, DRC1, and CCDC39. CONCLUSION: Through this study, we were able to confirm the value of WES as one of the diagnostic tools for PCD, which increases with TEM, rather than single gene tests. These results will prove useful to hospitals with limited access to PCD diagnostic testing but with relatively efficient in-house or outsourced access to genetic testing at a pre-symptomatic or early disease stage.

Clinical and genetic analysis of two patients with primary ciliary dyskinesia caused by a novel variant of DNAAF2.

BACKGROUND: The study describes the clinical manifestations and variant screening of two Chinese siblings with primary ciliary dyskinesia (PCD). They carry the same DNAAF2 genotype, which is an extremely rare PCD genotype in the Chinese population. In addition, the study illustrated an overview of published variants on DNAAF2 to date. METHODS: A two-child family was recruited for the study. Clinical manifestations, laboratory tests, bronchoscopic and otoscopic images, and radiographic data were collected. Whole blood was collected from siblings and their parents for whole-exome sequencing (WES) and Sanger sequencing to screen variants. RESULTS: The two siblings exhibited typical clinical manifestations of PCD. Two compound heterozygous variants in DNAAF2 were detected in both by WES. Nonsense variant c.156 C>A and frameshift variant c.177_178insA, which was a novel variant. CONCLUSION: The study identified a novel variant of DNAAF2 in Chinese children with a typical phenotype of PCD, which may enrich our knowledge of the clinical, diagnostic and genetic information of DNAAF2-induced PCD in children.

Role of Nasal Nitric Oxide in Primary Ciliary Dyskinesia and Other Respiratory Conditions in Children.

Nitric oxide (NO) is produced within the airways and released with exhalation. Nasal NO (nNO) can be measured in a non-invasive way, with different devices and techniques according to the age and cooperation of the patients. Here, we conducted a narrative review of the literature to examine the relationship between nNO and some respiratory diseases with a particular focus on primary ciliary dyskinesia (PCD). A total of 115 papers were assessed, and 50 were eventually included in the review. nNO in PCD is low (below 77 nL/min), and its measurement has a clear diagnostic value when evaluated in a clinically suggestive phenotype. Many studies have evaluated the role of NO as a molecular mediator as well as the association between nNO values and genotype or ciliary function. As far as other respiratory diseases are concerned, nNO is low in chronic rhinosinusitis and cystic fibrosis, while increased values have been found in allergic rhinitis. Nonetheless, the role in the diagnosis and prognosis of these conditions has not been fully clarified.

[Diagnostic value of nasal nitric oxide for children with primary ciliary dyskinesia].

Objective: To evaluate the value of nasal nitric oxide (nNO) measurement as a diagnostic tool for Chinese patients with primary ciliary dyskinesia (PCD). Methods: This study is a retrospective study. The patients were recruited from those who were admitted to the respiratory Department of Respiratory Medicine, Children's Hospital of Fudan University from March 2018 to September 2022. Children with PCD were included as the PCD group, and children with situs inversus or ambiguus, cystic fibrosis (CF), bronchiectasis, chronic suppurative lung disease and asthma were included as the PCD symptom-similar group. Children who visited the Department of Child health Care and urology in the same hospital from December 2022 to January 2023 were selected as nNO normal control group. nNO was measured during plateau exhalation against resistance in three groups. Mann-Whitney U test was used to analyze the nNO data. The receiver operating characteristic of nNO value for the diagnosis of PCD was plotted and, the area under the curve and Youden index was calculated to find the best cut-off value. Results: nNO was measured in 40 patients with PCD group, 75 PCD symptom-similar group (including 23 cases of situs inversus or ambiguus, 8 cases of CF, 26 cases of bronchiectasis or chronic suppurative lung disease, 18 cases of asthma), and 55 nNO normal controls group. The age of the three groups was respectively 9.7 (6.7,13.4), 9.3 (7.0,13.0) and 9.9 (7.3,13.0) years old. nNO values were significantly lower in children with PCD than in PCD symptom-similar group and nNO normal controls (12 (9,19) vs. 182 (121,222), 209 (165,261) nl/min, U=143.00, 2.00, both P<0.001). In the PCD symptom-similar group, situs inversus or ambiguus, CF, bronchiectasis or chronic suppurative lung disease and asthma were significantly higher than children with PCD (185 (123,218), 97 (52, 132), 154 (31, 202), 266 (202,414) vs. 12 (9,19) nl/min,U=1.00, 9.00, 133.00, 0, all P<0.001). A cut-off value of 84 nl/min could provide the best sensitivity (0.98) and specificity (0.92) with an area under the curve of 0.97 (95%CI 0.95-1.00, P<0.001). Conclusions: nNO value can draw a distinction between patients with PCD and others. A cut-off value of 84 nl/min is recommended for children with PCD.

Primary Ciliary Dyskinesia in a Portuguese Bronchiectasis Outpatient Clinic.

Primary ciliary dyskinesia (PCD) is a rare hereditary condition characterized by decreased mucociliary clearance of the airways and a compromised reproductive system, resulting in male and female infertility. Several mutations with varied clinical and pathological features have been documented, making diagnosis a challenging process. The purpose of this study is to describe the clinical and pathological features of Portuguese patients with PCD and to examine their genetic variants. A retrospective observational analysis was conducted with patients who were being monitored at a bronchiectasis outpatient clinic in 2022 and had a confirmed or high-likelihood diagnosis of PCD. In total, 17 patients were included in the study, with 12 (66.7%) having PCD confirmed and 5 (29.4%) having a high-likelihood diagnosis. Furthermore, 12 patients were subjected to transmission electron microscopy (TEM), with 7 (58.3%) exhibiting one hallmark defect. Genetic test data was obtained for all 17 patients, with 7 of them (41.2%) displaying a pathogenic/likely pathogenic mutation in homozygosity. To summarize, PCD is an uncommon but significant hereditary illness with consequences regarding morbidity and mortality. Despite the lack of a specific treatment, it is critical to confirm the diagnosis with genetic testing in order to effectively manage the disease and its accompanying disorders.

Nasal nitric oxide measurement in children for the diagnosis of primary ciliary dyskinesia: European Respiratory Society technical standard.

Nasal nitric oxide (nNO) is extremely low in most people with primary ciliary dyskinesia (PCD) and its measurement is an important contributor to making the diagnosis. Existing guidelines and technical standards focus on nNO measurements in older, cooperative children using chemiluminescence analysers. However, measurements of nNO in pre-school-age children (age 2-5 years) may facilitate early diagnosis and electrochemical rather than chemiluminescence analysers are widely used. Pre-schoolers often need different methods to be employed when measuring nNO. Hence, a European Respiratory Society Task Force has developed this technical standard as the first step towards standardising sampling, analysis and reporting of nNO measured as part of the diagnostic testing for PCD in all age groups, including pre-school-age children. Furthermore, we considered both chemiluminescence and electrochemical analysers that are in use worldwide. There was a paucity of quality evidence for electrochemical analysers and sampling methods used in young children, and the Task Force proposes future research priorities to allow updates of this technical standard.

Primary ciliary dyskinesia: A multicenter survey on clinical practice and patient management in Italy.

INTRODUCTION: There are no recent data on primary ciliary dyskinesia (PCD) distribution, diagnosis and treatment in Italy. METHODS: A descriptive study based on a survey questionnaire. It consisted of three sections (patients, diagnosis, and treatment), and sent to all the Italian PCD Centers. RESULTS: Questionnaires obtained from 20/22 centers in 12/20 regions showed that the total number of PCD patients treated at the participating centers was of 416. Out of all centers, 55% follow <20 patients, two centers have >40 patients, and 75% follow both pediatric and adults. Age at diagnosis was between 4 and 8 years in 45% of the centers, <3 years in three centers. Nasal nitric oxide, transmission electron microscopy and ciliary high-speed video microscopy are performed in 75%, 90%, and 40% of centers, respectively. Immunofluorescence is available in five centers. Genetic analysis is offered in 55% of the centers, and in seven centers >50% of the patients have a known genetic profile. Patients treated at all centers receive inhaled saline solutions, corticosteroids and chest physiotherapy. Prophylactic antibiotics and mucolytics are prescribed in 95% and 50% of the centers, respectively. Pseudomonas infection is treated with oral or inhaled antibiotics. CONCLUSIONS: Many Italian centers care for a small number of pediatric and adult patients, and diagnosis is often delayed. We found a great variability in the available diagnostic procedures, as well in the prescribed therapies. Our study will help to uniform diagnostic algorithm and share treatments protocols for PCD in Italy and allowed to set specific national goals.

Diagnostic value of nasal nitric oxide for children with primary ciliary dyskinesia / 中华儿科杂志

Objective: To evaluate the value of nasal nitric oxide (nNO) measurement as a diagnostic tool for Chinese patients with primary ciliary dyskinesia (PCD). Methods: This study is a retrospective study. The patients were recruited from those who were admitted to the respiratory Department of Respiratory Medicine, Children's Hospital of Fudan University from March 2018 to September 2022. Children with PCD were included as the PCD group, and children with situs inversus or ambiguus, cystic fibrosis (CF), bronchiectasis, chronic suppurative lung disease and asthma were included as the PCD symptom-similar group. Children who visited the Department of Child health Care and urology in the same hospital from December 2022 to January 2023 were selected as nNO normal control group. nNO was measured during plateau exhalation against resistance in three groups. Mann-Whitney U test was used to analyze the nNO data. The receiver operating characteristic of nNO value for the diagnosis of PCD was plotted and, the area under the curve and Youden index was calculated to find the best cut-off value. Results: nNO was measured in 40 patients with PCD group, 75 PCD symptom-similar group (including 23 cases of situs inversus or ambiguus, 8 cases of CF, 26 cases of bronchiectasis or chronic suppurative lung disease, 18 cases of asthma), and 55 nNO normal controls group. The age of the three groups was respectively 9.7 (6.7,13.4), 9.3 (7.0,13.0) and 9.9 (7.3,13.0) years old. nNO values were significantly lower in children with PCD than in PCD symptom-similar group and nNO normal controls (12 (9,19) vs. 182 (121,222), 209 (165,261) nl/min, U=143.00, 2.00, both P<0.001). In the PCD symptom-similar group, situs inversus or ambiguus, CF, bronchiectasis or chronic suppurative lung disease and asthma were significantly higher than children with PCD (185 (123,218), 97 (52, 132), 154 (31, 202), 266 (202,414) vs. 12 (9,19) nl/min,U=1.00, 9.00, 133.00, 0, all P<0.001). A cut-off value of 84 nl/min could provide the best sensitivity (0.98) and specificity (0.92) with an area under the curve of 0.97 (95%CI 0.95-1.00, P<0.001). Conclusions: nNO value can draw a distinction between patients with PCD and others. A cut-off value of 84 nl/min is recommended for children with PCD.

Nasal Nitric Oxide Levels: Improving the Diagnosis of Primary Ciliary Dyskinesia in Puerto Rico.

Primary Ciliary Dyskinesia (PCD) is a rare genetic disease characterized by motile cilia dysfunction with a prevalence of 1 in 16,309 individuals in Hispanic populations. In Puerto Rico, the prevalence of PCD is unknown. Diagnosis of PCD in Puerto Rico is challenging due to the lack of diagnostic technology. Algorithms for PCD diagnosis include clinical history, genetic testing, ciliary biopsy, and nasal Nitric Oxide (nNO) levels. For the first time, this study successfully implemented and measured the nNO levels in subjects with the RSPH4A (c.921+3_921+6del (intronic)) as a diagnostic tool to complement the current algorithm for PCD diagnosis on the island. The nNO level differentiated homozygous subjects with PCD due to the RSPH4A (c.921+3_921+6del (intronic)) founder mutation compared to healthy gender-age matched controls and subjects with VUS or negative genetic testing for PCD. The acquisition of state-of-the-art diagnostic tools such as nNO positively impacted and expanded our current PCD diagnostic capabilities in Puerto Rico for our founder genetic mutation. The addition of nNO technology promotes earlier disease screening and recognition for patients with PCD on the island. The access to nNO helped us to properly characterize the PCD diagnosis for patients with the RSPH4A (c.921+3_921+6del (intronic)). As a result, our findings will allow us to be part of the national PCD foundation registry and represent Puerto Rican Hispanics in future PCD multicentric clinical trials.

In vitro measurement of ciliary beat frequency in 92 children with recurrent respiratory tract problems.

BACKGROUND: Chronic or recurrent mucoid respiratory tract symptoms may be difficult to diagnose. METHOD: Ninety-two children with chronic respiratory symptoms were divided into 4 groups: 18 children with refractory asthma, 10 with bronchiectasis without dextrocardia, 18 with dextrocardia and 46 with recurrent respiratory tract infections. Except for five neonates, cytology samples were taken under general anaesthesia. Ciliary beat frequency was measured photometrically and analysed by in-house computer software. RESULTS: Nasal polyps were found in one child with normal ciliary beat frequency. Twenty-six children had no beating cilia (male to female ratio, 15:11). The effect of increasing temperature on the ciliary beat frequency of the remaining 66 patients was evaluated (42 patients, more than 30°C, median, 8.3 Hz; 24 patients, 30-37°C, median, 11.8 Hz; p = 0.0003). CONCLUSION: The measurement of ciliary beat frequency is part of the diagnostic work up of patients with persistent or recurrent respiratory tract infections.

Young's syndrome, a rare syndrome that can cause infertility and mimics cystic fibrosis and immotile-cilia syndrome: a case report.

INTRODUCTION: Young's syndrome (YS) is a rare, inherited syndrome commonly seen in middle-aged men with chronic rhinosinusitis, nasal polyps, decreased fertility due to azoospermia, and bronchiectasis. In this paper, we present a case of YS of unknown cause together with a literature review. CASE PRESENTATION: A 28-year-old male patient with the complaints of cough, sputum, recurrent nasal congestion, and shortness of breath lasting for more than ten years, was admitted to our clinic after bronchiectasis was observed in the thoracic computed tomography. CONCLUSIONS: An accurate diagnosis of YS is usually made late, which reduces patients' quality of life and leads to chronic respiratory problems. Failure to diagnose this disease may expose the patient to unnecessary and repeated hospitalizations and examinations, and result in treatment failure.

Progress in diagnosis of primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is an autosomal recessive genetic disorder characterised by motor ciliary dysfunction. The main manifestations are bronchiectasis, chronic sinusitis and situs inversus (viscera translocation triad). Additionally, it can present as male infertility and female ectopic pregnancy. However, there is currently no recognised diagnostic standard for PCD, which brings great challenges to its diagnosis and treatment. In addition to clinical data, the current diagnostic methods of PCD mainly include PICADAR, nasal exhaled nitric oxide, transmission electron microscopy, high-resolution immunofluorescence, high-speed video microscopy analysis and gene detection. This article makes a comprehensive comparison of the above diagnostic methods and suggests that genetic detection technology will become the general trend of PCD diagnosis.