Clinical and Molecular Profiling in GNAO1 Permits Phenotype-Genotype Correlation.

BACKGROUND: Defects in GNAO1, the gene encoding the major neuronal G-protein Gαo, are related to neurodevelopmental disorders, epilepsy, and movement disorders. Nevertheless, there is a poor understanding of how molecular mechanisms explain the different phenotypes. OBJECTIVES: We aimed to analyze the clinical phenotype and the molecular characterization of GNAO1-related disorders. METHODS: Patients were recruited in collaboration with the Spanish GNAO1 Association. For patient phenotyping, direct clinical evaluation, analysis of homemade-videos, and an online questionnaire completed by families were analyzed. We studied Gαo cellular expression, the interactions of the partner proteins, and binding to guanosine triphosphate (GTP) and G-protein-coupled receptors (GPCRs). RESULTS: Eighteen patients with GNAO1 genetic defects had a complex neurodevelopmental disorder, epilepsy, central hypotonia, and movement disorders. Eleven patients showed neurological deterioration, recurrent hyperkinetic crisis with partial recovery, and secondary complications leading to death in three cases. Deep brain stimulation improved hyperkinetic crisis, but had inconsistent benefits in dystonia. The molecular defects caused by pathogenic Gαo were aberrant GTP binding and hydrolysis activities, an inability to interact with cellular binding partners, and reduced coupling to GPCRs. Decreased localization of Gαo in the plasma membrane was correlated with the phenotype of "developmental and epileptic encephalopathy 17." We observed a genotype-phenotype correlation, pathogenic variants in position 203 were related to developmental and epileptic encephalopathy, whereas those in position 209 were related to neurodevelopmental disorder with involuntary movements. Milder phenotypes were associated with other molecular defects such as del.16q12.2q21 and I344del. CONCLUSION: We highlight the complexity of the motor phenotype, which is characterized by fluctuations throughout the day, and hyperkinetic crisis with a distinct post-hyperkinetic crisis state. We confirm a molecular-based genotype-phenotype correlation for specific variants. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

ABCA3-related interstitial lung disease beyond infancy.

BACKGROUND: The majority of patients with childhood interstitial lung disease (chILD) caused by pathogenic variants in ATP binding cassette subfamily A member 3 (ABCA3) develop severe respiratory insufficiency within their first year of life and succumb to disease if not lung transplanted. This register-based cohort study reviews patients with ABCA3 lung disease who survived beyond the age of 1 year. METHOD: Over a 21-year period, patients diagnosed as chILD due to ABCA3 deficiency were identified from the Kids Lung Register database. 44 patients survived beyond the first year of life and their long-term clinical course, oxygen supplementation and pulmonary function were reviewed. Chest CT and histopathology were scored blindly. RESULTS: At the end of the observation period, median age was 6.3 years (IQR: 2.8-11.7) and 36/44 (82%) were still alive without transplantation. Patients who had never received supplemental oxygen therapy survived longer than those persistently required oxygen supplementation (9.7 (95% CI 6.7 to 27.7) vs 3.0 years (95% CI 1.5 to 5.0), p=0.0126). Interstitial lung disease was clearly progressive over time based on lung function (forced vital capacity % predicted absolute loss -1.1% /year) and on chest CT (increasing cystic lesions in those with repetitive imaging). Lung histology pattern were variable (chronic pneumonitis of infancy, non-specific interstitial pneumonia, and desquamative interstitial pneumonia). In 37/44 subjects, the ABCA3 sequence variants were missense variants, small insertions or deletions with in-silico tools predicting some residual ABCA3 transporter function. CONCLUSION: The natural history of ABCA3-related interstitial lung disease progresses during childhood and adolescence. Disease-modifying treatments are desirable to delay such disease course.

Genetic diagnosis of basal ganglia disease in childhood.

AIM: To correlate clinical, radiological, and biochemical features with genetic findings in children with bilateral basal ganglia lesions of unknown aetiology, and propose a diagnostic algorithm for early recognition. METHOD: Children with basal ganglia disease were recruited in a 2-year prospective multicentre study for clinical, biomarker, and genetic studies. Radiological pattern recognition was examined by hierarchical clustering analysis. RESULTS: We identified 22 genetic conditions in 30 out of 62 paediatric patients (37 males, 25 females; mean age at onset 2y, SD 3; range 0-10y; mean age at assessment 11y, range 1-25y) through gene panels (n=11), whole-exome sequencing (n=13), and mitochondrial DNA (mtDNA) sequencing (n=6). Genetic aetiologies included mitochondrial diseases (57%), Aicardi-Goutières syndrome (20%), and monogenic causes of dystonia and/or epilepsy (17%) mimicking Leigh syndrome. Radiological abnormalities included T2-hyperintense lesions (n=26) and lesions caused by calcium or manganese mineralization (n=9). Three clusters were identified: the pallidal, neostriatal, and striatal, plus the last including mtDNA defects in the oxidative phosphorylation system with prominent brain atrophy. Mitochondrial biomarkers showed poor sensitivity and specificity in children with mitochondrial disease, whereas interferon signature was observed in all patients with patients with Aicardi-Goutières syndrome. INTERPRETATION: Combined whole-exome and mtDNA sequencing allowed the identification of several genetic conditions affecting basal ganglia metabolism. We propose a diagnostic algorithm which prioritizes early use of next-generation sequencing on the basis of three clusters of basal ganglia lesions.

Clinical Implications of the Genetic Background in Pediatric Pulmonary Arterial Hypertension: Data from the Spanish REHIPED Registry.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a severe and rare disease with an important genetic background. The influence of genetic testing in the clinical classification of pediatric PAH is not well known and genetics could influence management and prognosis. OBJECTIVES: The aim of this work was to identify the molecular fingerprint of PH children in the REgistro de pacientes con HIpertensión Pulmonar PEDiátrica (REHIPED), and to investigate if genetics could have an impact in clinical reclassification and prognosis. METHODS: We included pediatric patients with a genetic analysis from REHIPED. From 2011 onward, successive genetic techniques have been carried out. Before genetic diagnosis, patients were classified according to their clinical and hemodynamic data in five groups. After genetic analysis, the patients were reclassified. The impact of genetics in survival free of lung transplantation was estimated by Kaplan-Meier curves. RESULTS: Ninety-eight patients were included for the analysis. Before the genetic diagnoses, there were idiopathic PAH forms in 53.1%, PAH associated with congenital heart disease in 30.6%, pulmonary veno-occlusive disease-PVOD-in 6.1%, familial PAH in 5.1%, and associated forms with multisystemic disorders-MSD-in 5.1% of the patients. Pathogenic or likely pathogenic variants were found in 44 patients (44.9%). After a genetic analysis, 28.6% of the cohort was "reclassified", with the groups of heritable PAH, heritable PVOD, TBX4, and MSD increasing up to 18.4%, 8.2%, 4.1%, and 12.2%, respectively. The MSD forms had the worst survival rates, followed by PVOD. CONCLUSIONS: Genetic testing changed the clinical classification of a significant proportion of patients. This reclassification showed relevant prognostic implications.

FARS1-related disorders caused by bi-allelic mutations in cytosolic phenylalanyl-tRNA synthetase genes: Look beyond the lungs!

Aminoacyl-tRNA synthetases (ARSs) catalyze the first step of protein biosynthesis (canonical function) and have additional (non-canonical) functions outside of translation. Bi-allelic pathogenic variants in genes encoding ARSs are associated with various recessive mitochondrial and multisystem disorders. We describe here a multisystem clinical phenotype based on bi-allelic mutations in the two genes (FARSA, FARSB) encoding distinct subunits for tetrameric cytosolic phenylalanyl-tRNA synthetase (FARS1). Interstitial lung disease with cholesterol pneumonitis on histology emerged as an early characteristic feature and significantly determined disease burden. Additional clinical characteristics of the patients included neurological findings, liver dysfunction, and connective tissue, muscular and vascular abnormalities. Structural modeling of newly identified missense mutations in the alpha subunit of FARS1, FARSA, showed exclusive mapping to the enzyme's conserved catalytic domain. Patient-derived mutant cells displayed compromised aminoacylation activity in two cases, while remaining unaffected in another. Collectively, these findings expand current knowledge about the human ARS disease spectrum and support a loss of canonical and non-canonical function in FARS1-associated recessive disease.

Recurrent wheezing during the first 3 years of life in a birth cohort of moderate-to-late preterm infants.

BACKGROUND: Data addressing short- and long-term respiratory morbidity in moderate-late preterm infants are limited. We aim to determine the incidence of recurrent wheezing and associated risk and protective factors in these infants during the first 3 years of life. METHODS: Prospective, multicenter birth cohort study of infants born at 32+0 to 35+0  weeks' gestation and followed for 3 years to assess the incidence of physician-diagnosed recurrent wheezing. Allergen sensitization and pulmonary function were also studied. We used multivariate mixed-effects models to identify risk factors associated with recurrent wheezing. RESULTS: A total of 977 preterm infants were enrolled. Rates of recurrent wheezing during year (Y)1 and Y2 were similar (19%) but decreased to 13.3% in Y3. Related hospitalizations significantly declined from 6.3% in Y1 to 0.75% in Y3. Independent risk factors for recurrent wheezing during Y2 and Y3 included the following: day care attendance, acetaminophen use during pregnancy, and need for mechanical ventilation. Atopic dermatitis on Y2 and male sex on Y3 were also independently associated with recurrent wheezing. Palivizumab prophylaxis for RSV during the first year of life decreased the risk or recurrent wheezing on Y3. While there were no differences in rates of allergen sensitization, pulmonary function tests (FEV0.5 ) were significantly lower in children who developed recurrent wheezing. CONCLUSIONS: In moderate-to-late premature infants, respiratory symptoms were associated with lung morbidity persisted during the first 3 years of life and were associated with abnormal pulmonary function tests. Only anti-RSV prophylaxis exerted a protective effect in the development of recurrent wheezing.

New reference ranges for interpreting forced expiratory manoeuvres in infants and implications for clinical interpretation: a multicentre collaboration.

UNLABELLED: The raised volume rapid thoracoabdominal compression (RVRTC) technique is commonly used to obtain full forced expiratory manoeuvres from infants, but reference equations derived from 'in-house' equipment have been shown to be inappropriate for current commercially available devices. AIM: To explore the impact of equipment differences on RVRTC outcomes, derive robust equipment-specific RVRTC reference ranges and investigate their potential clinical impact on data interpretation. METHOD: RVRTC data from healthy subjects using Jaeger BabyBody or the 'Respiratory Analysis Software Program, RASP' systems were collated from four centres internationally. Data were excluded if gestational age <37 weeks or birth weight <2.5 kg. Reference equations for RVRTC outcomes were constructed using the LMS (lambda-mu-sigma) method, and compared with published equations using data from newborn screened infants with cystic fibrosis (CF). RESULTS: RVRTC data from 429 healthy infants (50.3% boys; 88% white infants) on 639 occasions aged 4-118 weeks were available. When plotted against length, flows were significantly higher with RASP than Jaeger, requiring construction of separate equipment-specific regression equations. When comparing results derived from the new equations with those from widely used published equations based on different equipments, discrepancies in forced expiratory volumes and flows of up to 2.5 z-scores were observed, the magnitude of which increased with age. According to published equations, 25% of infants with CF fell below the 95% limits of normal for FEV0.5, compared with only 10% when using the new equations. CONCLUSIONS: Use of equipment-specific prediction equations for RVRTC outcomes will enhance interpretation of infant lung function results; particularly during longitudinal follow-up.

Risk factors for bronchiolitis, recurrent wheezing, and related hospitalization in preterm infants during the first year of life.

BACKGROUND: Airway diseases are highly prevalent in infants and cause significant morbidity. We aimed to determine the incidence and risk factors for respiratory morbidity in a Spanish cohort of moderate-to-late preterm (MLP) infants prospectively followed during their first year of life. METHODS: SAREPREM is a multicenter, prospective, longitudinal study. Preterm infants born at 32-35 weeks of gestation with no comorbidities were enrolled within 2 weeks of life and followed at 2-4 weeks, 6, and 12 months of age. Multivariate mixed-models were performed to identify independent risk factors associated with (i) development of bronchiolitis, (ii) recurrent wheezing, or (iii) related hospital admissions. RESULTS: Overall, 977 preterm infants were included, and 766 (78.4%) completed follow-up. Of those, 365 (47.7%) developed bronchiolitis during the first year, 144 (18.8%) recurrent wheezing, and 48 (6.3%) were hospitalized. While low birthweight, day care attendance (DCA) and school-age siblings were significantly and independently associated with both the development of bronchiolitis and recurrent wheezing, lower maternal age increased the risk for bronchiolitis and respiratory-related hospitalizations. Lastly, mechanical ventilation was associated with a higher risk of bronchiolitis and history of asthma in any parent increased the likelihood of developing recurrent wheezing. CONCLUSIONS: In this study, several non-modifiable parameters (family history of asthma, low birthweight, need for mechanical ventilation) and modifiable parameters (young maternal age, DCA, or exposure to school-age siblings) were identified as significant risk factors for the development of bronchiolitis and recurrent wheezing during the first year of life in MLP infants.

Primary Ciliary Dyskinesia and Retinitis Pigmentosa: Novel RPGR Variant and Possible Modifier Gene.

We report a novel RPGR missense variant co-segregated with a familial X-linked retinitis pigmentosa (XLRP) case. The brothers were hemizygous for this variant, but only the proband presented with primary ciliary dyskinesia (PCD). Thus, we aimed to elucidate the role of the RPGR variant and other modifier genes in the phenotypic variability observed in the family and its impact on motile cilia. The pathogenicity of the variant on the RPGR protein was evaluated by in vitro studies transiently transfecting the mutated RPGR gene, and immunofluorescence analysis on nasal brushing samples. Whole-exome sequencing was conducted to identify potential modifier variants. In vitro studies showed that the mutated RPGR protein could not localise to the cilium and impaired cilium formation. Accordingly, RPGR was abnormally distributed in the siblings' nasal brushing samples. In addition, a missense variant in CEP290 was identified. The concurrent RPGR variant influenced ciliary mislocalisation of the protein. We provide a comprehensive characterisation of motile cilia in this XLRP family, with only the proband presenting PCD symptoms. The variant's pathogenicity was confirmed, although it alone does not explain the respiratory symptoms. Finally, the CEP290 gene may be a potential modifier for respiratory symptoms in patients with RPGR mutations.

Arrangement of residence before hospital discharge for children on home-invasive mechanical ventilation.

Children on long-term home mechanical ventilation are a growing population due to clinical and technological advances and the benefit for the child's quality of life. Invasive home ventilation is one of the most complex therapies offered in the home setting, requiring adequate home environment and appropriate equipment and supplies before discharge. The transition from hospital to home represents a vulnerable period that can be facilitated with an established transition plan with multidisciplinary team involvement. Readiness for home care is achieved when the patient is stable and has been transitioned from a critical care ventilator to a home mechanical ventilator. In parallel, comprehensive competency-based training regarding the knowledge and skills needed to help families use the equipment confidently and safely. Before discharge, families should be counseled on an adequate home environment to ensure a safe transition. The residence arrangement may include physical space modifications, verifying electrical installation, or moving to another home. Durable medical equipment and supplies must be ordered, and community healthcare support arranged. Parents should receive practical advice on setting up the equipment at home and on preventive measures to minimize complications related to tracheostomy and ventilator dependence, including regular maintenance and replacement of necessary equipment. Given the overall impact of invasive ventilation on home life, a structured home care action package is essential to alleviate the burdens involved.

Implementation of programmes for the transition of adolescents to adult care.

Up to 15-20% of adolescents have a chronic health problem. Adolescence is a period of particular risk for the development or progression of chronic diseases for both individuals with more prevalent conditions and those affected by rare diseases. The transition from paediatric to adult care begins with preparing and training the paediatric patient, accustomed to supervised care, to assume responsibility for their self-care in an adult care setting. The transition takes place when the young person is transferred to adult care and discharged from paediatric care services. It is only complete when the youth is integrated and functioning competently within the adult care system. Adult care providers play a crucial role in welcoming and integrating young adults. A care transition programme can involve transitions of varying complexity, ranging from those required for common and known diseases such as asthma, whose management is more straightforward, to rare complex disorders requiring highly specialized personnel. The transition requires teamwork with the participation of numerous professionals: paediatricians and adult care physicians, nurses, clinical psychologists, health social workers, the pharmacy team and administrative staff. It is essential to involve adolescents in decision-making and for parents to let them take over gradually. A well-structured transition programme can improve health outcomes, patient experience, the use of health care resources and health care costs.

Epigenetic regulation of inflammation by microRNAs in post-infectious bronchiolitis obliterans.

OBJECTIVES: Post-infectious bronchiolitis obliterans (PiBO) is a rare, chronic disease initiated by severe infection and followed by perpetuating inflammation and obliteration of the small airways. MicroRNAs (miRNAs) have been proposed to play a central role as epigenetic regulators, which control resolution and prevent the uncontrolled progress of inflammation. The aim of this study was to define biomarkers on the level of post-transcriptional gene regulation in order to characterise PiBO. METHODS: A total of 39 patients with well-defined PiBO and 31 controls from two centres, Barcelona, Spain, and Frankfurt, Germany, were analysed by next-generation sequencing (NGS). The evaluation of the biological targets of the miRNAs was performed by pathway enrichment analysis and protein-protein interaction network analysis respectively. RESULTS: Patients with PiBO had significantly lower lung function values and increased airway inflammation in induced sputum as indicated by total cell counts, neutrophils, IL-1ß, IL-6, IL-8 and TGF-ß compared to controls.Next-generation sequencing analysis revealed a total of 22 dysregulated miRNAs, which passed significance threshold for Padj ≤ 0.001 with 17 being upregulated and 5 being downregulated. Of these dysregulated miRNAs, miR-335-5p, miR-186-5p, miR-30b-5p and miR-30c-5p were further validated using qRT-PCR. Interestingly, these miRNAs are functionally implicated in cytokine-cytokine receptor interaction, TGF-ß signalling and FoxO signalling pathway and significantly correlated with lung function values (FEV1). CONCLUSION: Our results demonstrate an aberrant miRNA expression profile in PiBO, which impacts pathways responsible for the regulation of inflammation and fibrosis. The defined miRNAs are useful biomarkers and should be assessed as potential target in the field of miRNA therapeutics.

Development of Lung Function in Preterm Infants During the First Two Years of Life.

INTRODUCTION: It remains unclear if prematurity itself can influence post delivery lung development and particularly, the bronchial size. AIM: To assess lung function during the first two years of life in healthy preterm infants and compare the measurements to those obtained in healthy term infants during the same time period. METHODS: This observational longitudinal study assessed lung function in 74 preterm (30+0 to 35+6 weeks' gestational age) and 76 healthy term control infants who were recruited between 2011 and 2013. Measurements of tidal breathing, passive respiratory mechanics, tidal and raised volume forced expirations (V'maxFRC and FEF25-75, respectively) were undertaken following administration of oral chloral hydrate sedation according to ATS/ERS recommendations at 6- and 18-months corrected age. RESULTS: Lung function measurements were obtained from the preterm infants and full term controls initially at 6 months of age. Preterm infants had lower absolute and adjusted values (for gestational age, postnatal age, sex, body size, and confounding factors) for respiratory compliance and V'maxFRC. At 18 months corrected postnatal age, similar measurements were repeated in 57 preterm infants and 61 term controls. A catch-up in tidal volume, respiratory mechanics parameters, FEV0.5 and forced expiratory flows was seen in preterm infants. CONCLUSION: When compared with term controls, the lower forced expiratory flows observed in the healthy preterm group at 6 months was no longer evident at 18 months corrected age, suggesting a catch-up growth of airway function.

Incidence and Prevalence of Children's Diffuse Lung Disease in Spain.

BACKGROUND: Children's diffuse lung disease, also known as children's Interstitial Lung Diseases (chILD), are a heterogeneous group of rare diseases with relevant morbidity and mortality, which diagnosis and classification are very complex. Epidemiological data are scarce. The aim of this study was to analyse incidence and prevalence of chILD in Spain. METHODS: Multicentre observational prospective study in patients from 0 to 18 years of age with chILD to analyse its incidence and prevalence in Spain, based on data reported in 2018 and 2019. RESULTS: A total of 381 cases with chILD were notified from 51 paediatric pulmonology units all over Spain, covering the 91.7% of the paediatric population. The average incidence of chILD was 8.18 (CI 95% 6.28-10.48) new cases/million of children per year. The average prevalence of chILD was 46.53 (CI 95% 41.81-51.62) cases/million of children. The age group with the highest prevalence were children under 1 year of age. Different types of disorders were seen in children 2-18 years of age compared with children 0-2 years of age. Most frequent cases were: primary pulmonary interstitial glycogenosis in neonates (17/65), neuroendocrine cell hyperplasia of infancy in infants from 1 to 12 months (44/144), idiopathic pulmonary haemosiderosis in children from 1 to 5 years old (13/74), hypersensitivity pneumonitis in children from 5 to 10 years old (9/51), and scleroderma in older than 10 years old (8/47). CONCLUSIONS: We found a higher incidence and prevalence of chILD than previously described probably due to greater understanding and increased clinician awareness of these rare diseases.

International BEAT-PCD consensus statement for infection prevention and control for primary ciliary dyskinesia in collaboration with ERN-LUNG PCD Core Network and patient representatives.

INTRODUCTION: In primary ciliary dyskinesia (PCD) impaired mucociliary clearance leads to recurrent airway infections and progressive lung destruction, and concern over chronic airway infection and patient-to-patient transmission is considerable. So far, there has been no defined consensus on how to control infection across centres caring for patients with PCD. Within the BEAT-PCD network, COST Action and ERS CRC together with the ERN-Lung PCD core a first initiative has now been taken towards creating such a consensus statement. METHODS: A multidisciplinary international PCD expert panel was set up to create a consensus statement for infection prevention and control (IP&C) for PCD, covering diagnostic microbiology, infection prevention for specific pathogens considered indicated for treatment and segregation aspects. Using a modified Delphi process, consensus to a statement demanded at least 80% agreement within the PCD expert panel group. Patient organisation representatives were involved throughout the process. RESULTS: We present a consensus statement on 20 IP&C statements for PCD including suggested actions for microbiological identification, indications for treatment of Pseudomonas aeruginosa, Burkholderia cepacia and nontuberculous mycobacteria and suggested segregation aspects aimed to minimise patient-to-patient transmission of infections whether in-hospital, in PCD clinics or wards, or out of hospital at meetings between people with PCD. The statement also includes segregation aspects adapted to the current coronavirus disease 2019 (COVID-19) pandemic. CONCLUSION: The first ever international consensus statement on IP&C intended specifically for PCD is presented and is targeted at clinicians managing paediatric and adult patients with PCD, microbiologists, patient organisations and not least the patients and their families.

Implementation of a Gene Panel for Genetic Diagnosis of Primary Ciliary Dyskinesia. / Implementación de un panel de genes para el diagnóstico genético de la discinesia ciliar primaria.

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

Consensus Document on Community-Acquired Pneumonia in Children. SENP-SEPAR-SEIP. / Documento de consenso sobre la neumonía adquirida en la comunidad en los niños. SENP-SEPAR-SEIP.

Community-acquired pneumonia (CAP) is a prevalent disease among children and is frequently associated with both diagnostic and therapeutic uncertainties. Consensus has been reached between SEPAR, SENP and SEIP, and their conclusions are as follows.

Access to medicines for rare diseases: beating the drum for primary ciliary dyskinesia.

Primary ciliary dyskinesia, a rare disease causing bronchiectasis, lacks a sound evidence base for treatment. @beatpcd proposes 1) forming a PCD European clinical trial network to address this situation and 2) conducting n-of-1 trials to access medication. https://bit.ly/3j5blfM.

Immunofluorescence Analysis as a Diagnostic Tool in a Spanish Cohort of Patients with Suspected Primary Ciliary Dyskinesia.

Primary ciliary dyskinesia (PCD) is an autosomal recessive rare disease caused by an alteration of ciliary structure. Immunofluorescence, consisting in the detection of the presence and distribution of cilia proteins in human respiratory cells by fluorescence, has been recently proposed as a technique to improve understanding of disease-causing genes and diagnosis rate in PCD. The objective of this study is to determine the accuracy of a panel of four fluorescently labeled antibodies (DNAH5, DNALI1, GAS8 and RSPH4A or RSPH9) as a PCD diagnostic tool in the absence of transmission electron microscopy analysis. The panel was tested in nasal brushing samples of 74 patients with clinical suspicion of PCD. Sixty-eight (91.9%) patients were evaluable for all tested antibodies. Thirty-three cases (44.6%) presented an absence or mislocation of protein in the ciliary axoneme (15 absent and 3 proximal distribution of DNAH5 in the ciliary axoneme, 3 absent DNAH5 and DNALI1, 7 absent DNALI1 and cytoplasmatic localization of GAS8, 1 absent GAS8, 3 absent RSPH9 and 1 absent RSPH4A). Fifteen patients had confirmed or highly likely PCD but normal immunofluorescence results (68.8% sensitivity and 100% specificity). In conclusion, immunofluorescence analysis is a quick, available, low-cost and reliable diagnostic test for PCD, although it cannot be used as a standalone test.