The disease-specific clinical trial network for primary ciliary dyskinesia: PCD-CTN

Primary ciliary dyskinesia; Rare genetic disorder; Lung diseasesDiscinesia ciliar primaria; Trastorno genético raro; Enfermedades pulmonaresDiscinesia ciliar primària; Trastorn genètic rar; Malalties pulmonarsPrimary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by impaired mucociliary clearance leading to irreversible lung damage. In contrast to other rare lung diseases like cystic fibrosis (CF), there are only few clinical trials and limited evidence-based treatments. Management is mainly based on expert opinions and treatment is challenging due to a wide range of clinical manifestations and disease severity. To improve clinical and translational research and facilitate development of new treatments, the clinical trial network for PCD (PCD-CTN) was founded in 2020 under the framework of the European Reference Network (ERN)-LUNG PCD Core. Applications from European PCD sites interested in participating in the PCD-CTN were requested. Inclusion criteria consisted of patient numbers, membership of ERN-LUNG PCD Core, use of associated standards of care, experience in PCD and/or CF clinical research, resources to run clinical trials, good clinical practice (GCP) certifications and institutional support. So far, applications from 22 trial sites in 18 European countries have been approved, including >1400 adult and >1600 paediatric individuals with PCD. The PCD-CTN is headed by a coordinating centre and consists of a steering and executive committee, a data safety monitoring board and committees for protocol review, training and standardisation. A strong association with patient organisations and industrial companies are further cornerstones. All participating trial sites agreed on a code of conduct. As CTNs from other diseases have demonstrated successfully, this newly formed PCD-CTN operates to establish evidence-based treatments for this orphan disease and to bring new personalised treatment approaches to patients

The disease-specific clinical trial network for primary ciliary dyskinesia: PCD-CTN

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by impaired mucociliary clearance leading to irreversible lung damage. In contrast to other rare lung diseases like cystic fibrosis (CF), there are only few clinical trials and limited evidence-based treatments. Management is mainly based on expert opinions and treatment is challenging due to a wide range of clinical manifestations and disease severity. To improve clinical and translational research and facilitate development of new treatments, the clinical trial network for PCD (PCD-CTN) was founded in 2020 under the framework of the European Reference Network (ERN)-LUNG PCD Core. Applications from European PCD sites interested in participating in the PCD-CTN were requested. Inclusion criteria consisted of patient numbers, membership of ERN-LUNG PCD Core, use of associated standards of care, experience in PCD and/or CF clinical research, resources to run clinical trials, good clinical practice (GCP) certifications and institutional support. So far, applications from 22 trial sites in 18 European countries have been approved, including >1400 adult and >1600 paediatric individuals with PCD. The PCD-CTN is headed by a coordinating centre and consists of a steering and executive committee, a data safety monitoring board and committees for protocol review, training and standardisation. A strong association with patient organisations and industrial companies are further cornerstones. All participating trial sites agreed on a code of conduct. As CTNs from other diseases have demonstrated successfully, this newly formed PCD-CTN operates to establish evidence-based treatments for this orphan disease and to bring new personalised treatment approaches to patients

Estudio de la función de los cilios mediante imagen digital de alta velocidad. comparación con la ultraestructura ciliar en la discinesia ciliar primaria

Introducció La discinèsia ciliar primària (DCP) és una malaltia minoritària (1:15.000 nounats) caracteritzada per una alteració a l'estructura i funció ciliar que impedeix el correcte aclariment de les secrecions respiratòries. Les seves manifestacions clíniques inclouen tos productiva, rinitis crònica, otitis de repetició, bronquitis recurrents, bronquièctasis, infertilitat masculina, subfertilitat femenina i situs inversus (50%) o heterotaxia (6-12%). El diagnòstic es basava inicialment en la detecció de les alteracions estructurals mitjançant la microscòpia electrònica. S'han desenvolupat nous mètodes diagnòstics que contribueixen a facilitar el seu diagnòstic, tot i que aquest segueix sent difícil de realitzar. Objectius Valorar la utilitat diagnòstica de l'estudi de motilitat ciliar comparat amb l'estudi de la ultraestructura ciliar amb microscòpia electrònica. Establir valors de normalitat de l'estudi de motilitat ciliar. Descriure les característiques d'un grup de pacients afectes de discinèsia ciliar primària. Valorar la utilitat de les proves de despistatge d'aquesta malaltia: qüestionari de símptomes PICADAR i òxid nítric nasal en aquest grup de pacients i en una mostra ampliada. Mètodes Selecció d'una mostra de població normal per establir valors de referència de l'estudi de motilitat ciliar. Realització de l'estudi de motilitat ciliar en una mostra de pacients amb sospita de discinèsia ciliar estudiats prèviament mitjançant microscòpia electrònica i comparació de les dues tècniques. Valorar la utilitat com a proves de cribratge del qüestionari de símptomes PICADAR i de l'òxid nítric nasal en aquesta mostra de pacients i en una mostra ampliada Resultats Els valors de normalitat de l'estudi de motilitat ciliar van ser: freqüència de batec 9,94 Hz (8,56-11,32), índex de discinèsia 12,10% (2,54-21,66) i índex d'immobilitat 0,13% (0-1,51). Les característiques clíniques més importants que van definir al grup de pacients amb discinèsia ciliar primària van ser: patir distrès respiratori neonatal i presentar tos i rinorrea des del primer dia de vida. La majoria dels pacients amb situs inversus estaven en aquest grup. També presentaven més freqüència de tos contínua productiva, rinorrea persistent, major percentatge de sordesa i de sensació d'oïdes tapades que la resta dels grups. En el grup de pacients estudiats amb microscòpia electrònica la seva sensibilitat i especificitat va ser del 90,9%, i 48,3% i la de l'estudi de motilitat ciliar del 100% i 80%. En aquest grup, la sensibilitat i especificitat del qüestionari PICADAR va ser del 90,9%, i 86,7% (amb un punt de tall > 4 punts), i la de l'òxid nítric nasal del 80% i 100% (amb un punt de tall  220 ppb o  72,5 nL/min). A la mostra ampliada de pacients, la sensibilitat i especificitat de l'estudi de motilitat ciliar va ser del 100% i 82,8%, la del qüestionari PICADAR del 92,9% i el 71,7% (amb un punt de tall > 3 punts) i la de la mesura de l'òxid nítric nasal del 91,9% i el 97,5% (amb un punt de tall  248 ppb o  87,9 nL/min). Conclusions L'estudi de la motilitat ciliar (freqüència i patró de batec) mitjançant videomicroscòpia òptica va tenir una millor sensibilitat i sobretot una millor especificitat que l'estudi de la ultraestructura amb microscòpia electrònica per al diagnòstic de discinèsia ciliar primària. L'escala predictiva PICADAR i la determinació d'òxid nítric nasal són bones proves de cribratge de la discinèsia ciliar primària, la qual cosa s'ha confirmat tant en la mostra inicial com en la mostra ampliada de pacients.Introducción La discinesia ciliar primaria (DCP) es una enfermedad rara (1:15.000 recién nacidos) caracterizada por una alteración en la estructura y función ciliar que impide el correcto aclaramiento de las secreciones respiratorias. Sus manifestaciones clínicas incluyen tos productiva, rinitis crónica, otitis de repetición, bronquitis recurrentes, bronquiectasias, infertilidad masculina, subfertilidad femenina y situs inversus (50%) o heterotaxia (6-12%). El diagnóstico se basaba inicialmente en la detección de las alteraciones estructurales mediante la microscopía electrónica. Se han desarrollado nuevos métodos diagnósticos que contribuyen a facilitar su diagnóstico, aunque éste sigue siendo difícil de realizar. Objetivos Valorar la utilidad diagnóstica del estudio de motilidad ciliar comparado con el estudio de la ultraestructura ciliar con microscopía electrónica. Establecer valores de normalidad del estudio de motilidad ciliar. Describir las características de un grupo de pacientes afectos de discinesia ciliar primaria. Valorar la utilidad de las pruebas de despistaje de esta enfermedad: cuestionario de síntomas PICADAR y óxido nítrico nasal en este grupo de pacientes y en una muestra ampliada. Métodos Selección de una muestra de población normal para establecer valores de referencia del estudio de motilidad ciliar. Realización del estudio de motilidad ciliar en una muestra de pacientes con sospecha de discinesia ciliar estudiados previamente mediante microscopía electrónica y comparación de ambas técnicas. Valorar la utilidad como pruebas de despistaje del cuestionario de síntomas PICADAR y del óxido nítrico nasal en esta muestra de pacientes y en una muestra ampliada. Resultados Los valores de normalidad del estudio de motilidad ciliar fueron: frecuencia del batido 9,94 Hz (8,56-11,32), índice de discinesia 12,10% (2,54-21,66) e índice de inmovilidad 0,13% (0-1,51). Las características clínicas más importantes que definieron al grupo de pacientes con discinesia ciliar primaria fueron: padecer distrés respiratorio neonatal y presentar tos y rinorrea desde el primer día de vida. La mayoría de los pacientes con situs inversus estaban en este grupo. También presentaban más frecuencia de tos continua productiva, rinorrea persistente, mayor porcentaje de sordera y de sensación de oídos tapados que el resto de los grupos. En el grupo de pacientes estudiados con microscopía electrónica su sensibilidad y especificidad fue del 90,9% y 48,3% y la del estudio de motilidad ciliar del 100% y 80%. En este grupo, la sensibilidad y especificidad del cuestionario PICADAR fue del 90,9% y 86,7% (con un punto de corte > 4 puntos), y la del óxido nítrico nasal del 80% y 100% (con un punto de corte en  220 ppb o  72,5 nL/min). En la muestra ampliada de pacientes, la sensibilidad y especificidad del estudio de motilidad ciliar fue del 100% y 82,8%, la del cuestionario PICADAR del 92,9% y 71,7% (con un punto de corte > 3 puntos) y la de la medida del óxido nítrico nasal del 91,9% y 97,5% (con un punto de corte en  248 ppb o  87,9 nL/min). Conclusiones El estudio de la motilidad ciliar (frecuencia y patrón de batido) mediante videomicroscopía óptica tuvo una mejor sensibilidad y sobretodo una mejor especificidad que el estudio de la ultraestructura con microscopía electrónica para el diagnóstico de discinesia ciliar primaria. La escala predictiva PICADAR y la determinación de óxido nítrico nasal son buenas pruebas de despistaje de la discinesia ciliar primaria, lo que se ha confirmado tanto en la muestra inicial como en la muestra ampliada de pacientes.Introduction Primary ciliary dyskinesia (PCD) is a rare disease (1:15,000 newborns) characterized by an alteration in the ciliary structure and function that prevents the correct clearance of respiratory secretions. Its clinical manifestations include productive cough, chronic rhinitis, recurrent otitis, recurrent bronchitis, bronchiectasis, male infertility, female subfertility, and situs inversus (50%) or heterotaxia (6-12%). Some years ago, the diagnosis was based on the structural alterations detected by electron microscopy. New diagnostic methods have been developed to contribute its diagnosis, although it remains difficult to perform. Objectives To assess the diagnostic utility of the ciliary motility study compared with the study of the ciliary ultrastructure by electron microscopy. Establish normality values of the ciliary motility study. Describe the characteristics of a group of patients with primary ciliary dyskinesia. To assess the usefulness of screening tests for this disease: the PICADAR symptom questionnaire and nasal nitric oxide in this group of patients and in an extended sample. Methods Selection of a healthy population sample to establish reference values for the ciliary motility study. Ciliary motility study was performed in a sample of patients with suspected ciliary dyskinesia previously studied by electron microscopy and comparison of both techniques. To assess the usefulness of the PICADAR symptom questionnaire and nasal nitric oxide as screening tests in this sample of patients and in an extended sample. Results The normal values of the ciliary motility study were beat frequency 9.94 Hz (8.56-11.32), dyskinesia index 12.10% (2.54-21.66) and immotility index 0,13% (0-1.51). The most important clinical characteristics that defined the group of patients with primary ciliary dyskinesia were neonatal respiratory distress and presenting cough and rhinorrhea from the first day of life. Most of the patients with situs inversus were in this group. They also had a higher frequency of continuous productive cough, persistent rhinorrhea, a higher percentage of deafness and a sensation of blocked ears than the rest of the groups. In the group of patients studied by electron microscopy, its sensitivity and specificity were 90.9% and 48.3% and for the ciliary motility study was 100% and 80%. In this group, the sensitivity and specificity of the PICADAR questionnaire was 90.9% and 86.7% (with a cut-off point > 4 points), and for the nasal nitric oxide was 80% and 100% (with a point of cut-off at  220 ppb or  72.5 nL/min). For the expanded sample of patients, the sensitivity and specificity of the ciliary motility study was 100% and 82.8%, for the PICADAR questionnaire 92.9% and 71.7% (with a cut-off point > 3 points) and for the nasal nitric oxide measurement 91.9% and 97.5% (with a cut-off point of  248 ppb or  87.9 nL/min). Conclusions The study of ciliary motility (frequency and beat pattern) performed by high-speed videomicroscopy had better sensitivity and a better specificity than the study of the ultrastructure performed by electron microscopy for the diagnosis of primary ciliary dyskinesia. The PICADAR predictive questionnaire and the nasal nitric oxide determination are good screening tests for primary ciliary dyskinesia, which has been confirmed both in the initial sample and in the expanded sample of patients.Universitat Autònoma de Barcelona. Programa de Doctorat en Pediatria, Obstetrícia i Ginecologi

Caracterització molecular de la Discinèsia Ciliar Primària

Caracterització molecular; Discinèsia ciliar primària; Anàlisi genèticaMolecular characterization; Primary ciliary dyskinesia; Genetic analysisCaracterización molecular; Discinesia ciliar primaria; Análisis genéticoComunicació sobre com la caracterització molecular per a la discinèsia ciliar és útil per confirmar-ne el diagnòstic

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

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

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, althouh it cannot be used as a standalone tes

Implementation of a Gene Panel for Genetic Diagnosis of Primary Ciliary Dyskinesia

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