A novel mutation of DNAH5 in chronic rhinosinusitis and primary ciliary dyskinesia in a Chinese family

Clinical and genetic spectrum of primary ciliary dyskinesia in Chinese patients: a systematic review

Background

Primary ciliary dyskinesia (PCD) represents a highly heterogenous disorder with extensive clinical and genetic patterns among populations of different geographic location and ethnic origin. However, data about Chinese patients are limited. We aimed to summarize the clinical and genetic spectrum of Chinese PCD patients based on all available literatures.

Methods

We searched Embase, Pubmed, Web of Science and Chinese databases including CNKI, SinoMed and Wanfang from 1981 to 2021, to identify articles reporting patients with PCD in China, which had included information about transmission electron microscopy and/or genetic testing.

Results

A total of 244 Chinese PCD patients in 52 articles were included. Of these patients, the mean age was 13.1 years, and 55 patients (22.5%) were diagnosed with PCD after 18 years old. Compared with patients diagnosed with PCD in childhood or infancy, patients diagnosed with PCD in adulthood had a higher prevalence of chronic wet cough, sinusitis, Pseudomonas aeruginosa (PA) isolation and radiological bronchiectasis as well as worse lung function. 25 PCD-related genes were identified in 142 patients, and DNAH5, DNAH11, CCDC39 and CCDC40 were the most frequently detected mutations. More than half of genetic variants were loss-of-function mutations, and the majority of these variants were seen only once. Correlations between PCD phenotype, genotype and ciliary ultrastructure were also evidenced.

Conclusions

Diagnostic delay and under-recognition of PCD remain a big issue in China, which contributes to progressive lung disease and PA infection indicating worse outcome. Specialist equipment and expertise are urgently required to facilitate the early diagnosis and treatment of PCD.

Trial registry

PROSPERO; No.: CRD42021257804; URL:www.crd.york.ac.uk/prospero/

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02427-1.

Motile Ciliary Disorders in Chronic Airway Inflammatory Diseases: Critical Target for Interventions

PURPOSE OF REVIEW

Impaired mucociliary clearance has been implicated in chronic upper and lower airway inflammatory diseases (i.e., allergic and non-allergic rhinitis, chronic rhinosinusitis with or without nasal polyps and asthma). How motile ciliary disorders (impaired ciliogenesis, ciliary beating and ultrastructural defects) are implicated in chronic airway inflammatory diseases is not fully understood. Elaboration of the role of motile ciliary disorders may serve as therapeutic targets for improving mucociliary clearance, thereby complementing contemporary disease management.

RECENT FINDINGS

We have summarized the manifestations of motile ciliary disorders and addressed the underlying associations with chronic airway inflammatory diseases. A panel of established and novel diagnostic tests and therapeutic interventions are outlined. Physicians should be vigilant in screening for motile ciliary disorders, particularly in patients with co-existing upper and lower airway inflammatory diseases. Proper assessment and treatment of motile ciliary disorders may have added value to the management and prevention of chronic airway inflammatory diseases.

Whole-exome sequencing identification of novel DNAH5 mutations in a young patient with primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a rare genetic disorder caused by structural and/or functional impairment of cilia throughout the whole body. Early diagnosis of PCD is important for the prevention of long-term sequelae, however early diagnosis is a challenge due to the phenotypic heterogeneity of PCD. In the current study, the patient with PCD was diagnosed at nine years old following several efforts to control intractable airway symptoms. The patient experienced a chronic productive cough beginning in early childhood and had multiple episodes of pneumonia and otitis media with effusion and sinusitis. No situs inversus or other heterotaxias were reported. Serial chest X-rays exhibited persistent atelectasis and bronchiectasis in the right middle lobe. When the patient was nine years old, electron microscopy of his cilia and genetic analysis were conducted. Electron microscopy of a biopsy specimen from the nasal mucosa indicated loss of the outer dynein arms. Whole-exome analysis of the genome demonstrated the presence of compound heterozygous mutations in DNAH5: NM_001369.2:c.5983C>T, p.Arg1995X in exon 36 and NM_001369.2:c.9101delG, p.Gly3034ValfsX22 in exon 54; neither of which have been previously reported in the literature in a Japanese patient. Notably, this case is, to the best of our knowledge, the first reported case of PCD caused by the DNAH5 mutation in a Japanese patient.

Risk Factors and Comorbidities in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous disorder that creates a significant burden on the healthcare system. It is caused by a combination of inflammatory, environmental, and host factors; however, the precise mechanism of how each factor leads to CRS continues to be a source of debate. Previous data regarding this topic is often inconsistent or of lower quality. In this article, we review the recent literature on the risk factors and comorbidities in CRS. Large population-based studies have helped establish smoking as a significant risk factor for CRS. The focus has now shifted towards smoking and its effect on long-term outcomes after endoscopic sinus surgery (ESS). Ciliary dyskinesia, both primary and secondary, can affect both the sinonasal cavity and lower airways simultaneously by decreasing the beat frequency of cilia and inducing mucostasis. The effects of secondary dyskinesia may be reversible and there is some evidence to suggest the use of topical mucolytics in patients with CRS. Allergy and variants of sinonasal anatomy have been hypothesized to increase the risk of developing CRS by inducing chronic inflammation and obstructing the sinus ostia. Nevertheless, emerging data regarding these topics continue to produce inconclusive results. Inflammation of the upper and lower airways can occur simultaneously as seen in patients with asthma and aspirin sensitivity. The connection between these pro-inflammatory disease states has been known for many years. Newer evidence include large population-based studies and studies that correlate objective tests, such as computer tomography scans to pulmonary function tests. However, the treatment of CRS and its effects on obstructive airway disease continues to be a topic of debate. More large prospective studies are needed in order to continue refining our knowledge of the disease processes in CRS.