Defective airway intraflagellar transport underlies a combined motile and primary ciliopathy syndrome caused by IFT74 mutations

Ciliopathies are inherited disorders caused by defective cilia. Mutations affecting motile cilia usually cause the chronic muco-obstructive sinopulmonary disease primary ciliary dyskinesia (PCD) and are associated with laterality defects, while a broad spectrum of early developmental as well as degenerative syndromes arise from mutations affecting signalling of primary (non-motile) cilia. Cilia assembly and functioning requires intraflagellar transport of cargos assisted by IFT-B and IFT-A adaptor complexes. Within IFT-B, the N-termini of partner proteins IFT74 and IFT81 govern tubulin transport to build the ciliary microtubular cytoskeleton. We detected a homozygous 3 kb intragenic IFT74 deletion removing the exon 2 initiation codon and 40 N-terminal amino acids in two affected siblings. Both had clinical features of PCD with bronchiectasis, but no laterality defects. They also had retinal dysplasia and abnormal bone growth, with a narrowed thorax and short ribs, shortened long bones and digits and abnormal skull shape. This resembles short-rib thoracic dysplasia, a skeletal ciliopathy previously linked to IFT defects in primary cilia, not motile cilia. Ciliated nasal epithelial cells collected from affected individuals had reduced numbers of shortened motile cilia with disarranged microtubules, some mis-orientation of the basal feet, and disrupted cilia structural and IFT protein distributions. No full length IFT74 was expressed, only truncated forms that were consistent with N-terminal deletion and inframe translation from downstream initiation codons. In affinity purification mass spectrometry, exon 2-deleted IFT74 initiated from the nearest inframe downstream methionine 41 still interacts as part of the IFT-B complex, but only with reduced interaction levels and not with all its usual IFT-B partners. We propose that this is a hypomorphic mutation with some residual protein function retained, that gives rise to a non-lethal primary skeletal ciliopathy combined with defective motile cilia and PCD

The Palestinian primary ciliary dyskinesia (PCD) cohort: clinical, diagnostic and genetic spectrum

Background: Diagnostic testing for PCD started in 2013 in Palestine. We aimed to describe the clinical, diagnostic and genetic spectrum of the Palestinian PCD cohort. Methods: 390 individuals with symptoms suggestive of PCD and 74 family members underwent nasal nitric oxide (nNO); and/or transmission electron microscopy (TEM); and/or PCD genetic panel or whole exome testing. Clinical characteristics were collected close to diagnosis including FEV1 GLI z-scores and BMI z-scores. Results: 82 had a definite positive PCD diagnosis (TEM and/or genetics) and 103 were highly likely (Kartagener’s and/or low nNO). Positive cases (n=82) had median age of 13.5 years (range 0-43), were highly consanguineous (95%) and 100% Arabic descent. Clinical features included persistent wet cough (95%), neonatal respiratory distress (79%), clubbing (21%) and situs inversus (41%). Lung function at diagnosis was already impaired FEV1 z-score mean -1.49 (sd=1.79) and BMI z-score mean -0.30 SD=1.4. 69 families were genotyped. 59 individuals from 42 families (60%) had mutations in 14 PCD-genes; CCDC39 (26% of families), DNAH11 (17%) and LRRC6 (12%) were the most common. 16% had mutations in candidate genes, 24% had no variants identified. 100% of variants were homozygous. TEM defects and genotype associations were as expected. Conclusions: Despite limited local resources, collaborations during the last 7-years have facilitated detailed geno- and phenotyping of one of the largest PCD cohorts globally. nNO identifies likely cases and targeted genetic testing, conducted locally, can now identify specific mutations in known families

Proceedings of the 2nd BEAT-PCD conference and 3rd PCD training school: part 1

Primary ciliary dyskinesia (PCD) is a rare heterogenous condition that causes progressive suppurative lung disease, chronic rhinosinusitis, chronic otitis media, infertility and abnormal situs. 'Better Experimental Approaches to Treat Primary Ciliary Dyskinesia' (BEAT-PCD) is a network of scientists and clinicians coordinating research from basic science through to clinical care with the intention of developing treatments and diagnostics that lead to improved long-term outcomes for patients. BEAT-PCD activities are supported by EU funded COST Action (BM1407). The second BEAT-PCD conference, and third PCD training school were held jointly in April 2017 in Valencia, Spain. Presentations and workshops focussed on advancing the knowledge and skills relating to PCD in: basic science, epidemiology, diagnostic testing, clinical management and clinical trials. The multidisciplinary conference provided an interactive platform for exchanging ideas through a program of lectures, poster presentations, breakout sessions and workshops. Three working groups met to plan consensus statements. Progress with BEAT-PCD projects was shared and new collaborations were fostered. In this report, we summarize the meeting, highlighting developments made during the meeting

Standardised clinical data from patients with primary ciliary dyskinesia:FOLLOW-PCD

Clinical data on primary ciliary dyskinesia (PCD) are limited, heterogeneous and mostly derived from retrospective chart reviews, leading to missing data and unreliable symptoms and results of physical examinations. We need standardised prospective data collection to study phenotypes, severity and prognosis and improve standards of care.A large, international and multidisciplinary group of PCD experts developed FOLLOW-PCD, a standardised clinical PCD form and patient questionnaire. We identified existing forms for clinical data collection via the Better Experimental Approaches to Treat PCD (BEAT-PCD) COST Action network and a literature review. We selected and revised the content items with the working group and patient representatives. We then revised several drafts in an adapted Delphi process, refining the content and structure.FOLLOW-PCD has a modular structure, to allow flexible use based on local practice and research focus. It includes patient-completed versions for the modules on symptoms and lifestyle. The form allows a comprehensive standardised clinical assessment at baseline and for annual reviews and a short documentation for routine follow-up. It can either be completed using printable paper forms or using an online REDCap database.Data collected in FOLLOW-PCD version 1.0 is available in real-time for national and international monitoring and research. The form will be adapted in the future after extensive piloting in different settings and we encourage the translation of the patient questionnaires to multiple languages. FOLLOW-PCD will facilitate quality research based on prospective standardised data from routine care, which can be pooled between centres, to provide first-line and real-time evidence for clinical decision-making

The Palestinian primary ciliary dyskinesia population: first results of the diagnostic, and genetic spectrum

BACKGROUND: Diagnostic testing for primary ciliary dyskinesia (PCD) started in 2013 in Palestine. We aimed to describe the diagnostic, genetic and clinical spectrum of the Palestinian PCD population. METHODS: Individuals with symptoms suggestive of PCD were opportunistically considered for diagnostic testing: nasal nitric oxide (nNO) measurement, transmission electron microscopy (TEM) and/or PCD genetic panel or whole-exome testing. Clinical characteristics of those with a positive diagnosis were collected close to testing including forced expiratory volume in 1 s (FEV1) Global Lung Index z-scores and body mass index z-scores. RESULTS: 68 individuals had a definite positive PCD diagnosis, 31 confirmed by genetic and TEM results, 23 by TEM results alone, and 14 by genetic variants alone. 45 individuals from 40 families had 17 clinically actionable variants and four had variants of unknown significance in 14 PCD genes. CCDC39, DNAH11 and DNAAF11 were the most commonly mutated genes. 100% of variants were homozygous. Patients had a median age of 10.0 years at diagnosis, were highly consanguineous (93%) and 100% were of Arabic descent. Clinical features included persistent wet cough (99%), neonatal respiratory distress (84%) and situs inversus (43%). Lung function at diagnosis was already impaired (FEV1 z-score median −1.90 (−5.0–1.32)) and growth was mostly within the normal range (z-score mean −0.36 (−3.03–2.57). 19% individuals had finger clubbing. CONCLUSIONS: Despite limited local resources in Palestine, detailed geno- and phenotyping forms the basis of one of the largest national PCD populations globally. There was notable familial homozygosity within the context of significant population heterogeneity

Proceedings of the 3rd BEAT-PCD Conference and 4th PCD Training School

Abstract Primary ciliary dyskinesia (PCD) is a chronic suppurative airways disease that is usually recessively inherited and has marked clinical phenotypic heterogeneity. Classic symptoms include neonatal respiratory distress, chronic rhinitis since early childhood, chronic otitis media, recurrent airway infections leading to bronchiectasis, chronic sinusitis, laterality defects with and without congenital heart disease including abnormal situs in approximately 50% of the cases, and male infertility. Lung function deteriorates progressively from childhood throughout life. ‘Better Experimental Approaches to Treat Primary Ciliary Dyskinesia’ (BEAT-PCD) is a network of scientists and clinicians coordinating research from basic science through to clinical care with the intention of developing treatments and diagnostics that lead to improved long-term outcomes for patients. BEAT-PCD activities are supported by EU funded COST Action (BM1407). The third BEAT-PCD conference and fourth PCD training school were held jointly in February 2018 in Lisbon, Portugal. Presentations and workshops focussed on advancing the knowledge and skills relating to PCD in: basic science, epidemiology, diagnostic testing, clinical management and clinical trials. The multidisciplinary conference provided an interactive platform for exchanging ideas through a program of lectures, poster presentations, breakout sessions and workshops. Three working groups met to plan consensus statements. Progress with BEAT-PCD projects was shared and new collaborations were fostered. In this report, we summarize the meeting, highlighting developments made during the meeting

Clinical utility of NGS diagnosis and disease stratification in a multiethnic primary ciliary dyskinesia cohort

Background Primary ciliary dyskinesia (PCD), a genetically heterogeneous condition enriched in some consanguineous populations, results from recessive mutations affecting cilia biogenesis and motility. Currently, diagnosis requires multiple expert tests.Methods The diagnostic utility of multigene panel next-generation sequencing (NGS) was evaluated in 161 unrelated families from multiple population ancestries.Results Most (82%) families had affected individuals with biallelic or hemizygous (75%) or single (7%) pathogenic causal alleles in known PCD genes. Loss-of-function alleles dominate (73% frameshift, stop-gain, splice site), most (58%) being homozygous, even in non-consanguineous families. Although 57% (88) of the total 155 diagnostic disease variants were novel, recurrent mutations and mutated genes were detected. These differed markedly between white European (52% of families carry DNAH5 or DNAH11 mutations), Arab (42% of families carry CCDC39 or CCDC40 mutations) and South Asian (single LRRC6 or CCDC103 mutations carried in 36% of families) patients, revealing a striking genetic stratification according to population of origin in PCD. Genetics facilitated successful diagnosis of 81% of families with normal or inconclusive ultrastructure and 67% missing prior ultrastructure results.Conclusions This study shows the added value of high-throughput targeted NGS in expediting PCD diagnosis. Therefore, there is potential significant patient benefit in wider and/or earlier implementation of genetic screening

Subxiphoid uniportal video assisted thoracoscopic lobectomy in a pediatric patient

Thoracoscopic surgeries have witnessed tremendous and prompt recent development, especially in the field of uniportal video assisted thoracoscopic surgery (VATS) surgery. It is now possible to perform the most complex surgeries through this technique, which is of great benefit to the patient by significantly reducing the level of postoperative pain and complications of surgery. As surgeons gain experience in this field, their confidence and ability to push the limits and develop technologies are increasing. Performing uniportal VATS surgeries in children is a significant challenge for the surgeon due to the limited size of the thoracic cavity and the difficulty of the instrumentation. Here, we report the first case in the literature (as far as we know) of a uniportal Subxiphoid VATS lobectomy in a 2.5-year-old child. In conclusion, Subxiphoid uniportal VATS lobectomy is feasible in pediatric patients and may have some benefits over the intercostal approach

Uniportal video assisted thoracoscopic left upper bronchial sleeve lobectomy in a pediatric patient

Endo-bronchial tumors are sporadic in the pediatric population. Pneumonectomy is rarely indicated and best to be avoided if possible due to the morbidity it may cause. In children, preserving as much of the lung parenchymal tissue as possible is crucial and maintaining the integrity of the "still maturing" chest wall may reduce the risk of developing scoliosis and chest deformities in the future. The integration of minimally invasive surgical techniques and parenchymal sparing procedures rep-resents the best possible outcome for these patients. Of course, oncological principles should be re-spected when such a procedure is performed. We present the first report in the literature of a "left" upper lobe sleeve resection in an 8 year old patient via a single port video-assisted thoracoscopic surgery technique

Diagnosis of primary ciliary dyskinesia: potential options for resource-limited countries

Primary ciliary dyskinesia is a genetic disease of ciliary function leading to chronic upper and lower respiratory tract symptoms. The diagnosis is frequently overlooked because the symptoms are nonspecific and the knowledge about the disease in the primary care setting is poor. Additionally, none of the available tests is accurate enough to be used in isolation. These tests are expensive, and need sophisticated equipment and expertise to analyse and interpret results; diagnosis is therefore only available at highly specialised centres. The diagnosis is particularly challenging in countries with limited resources due to the lack of such costly equipment and expertise. In this review, we discuss the importance of early and accurate diagnosis especially for countries where the disease is clinically prevalent but diagnostic tests are lacking. We review the diagnostic tests available in specialised centres (nasal nitric oxide, high-speed video microscopy, transmission electron microscopy, immunofluorescence and genetics). We then consider modifications that might be considered in less well-resourced countries whilst maintaining acceptable accuracy