Primary ciliary dyskinesia (PCD) is a recessive genetic disorder of motile cilia with substantial genetic and phenotypic heterogeneity. Clinical features of PCD vary from one patient to another, and no single test has the sensitivity and specificity to accurately diagnose PCD. Genetic testing combined with other auxiliary tests can facilitate the confirmatory diagnosis of PCD. So far more than 40 genes have been associated with PCD, but most research have focused on common genes, which hinders our understanding of other rare PCD-genes. This review has summarized the PCD-associated genes and the corresponding characteristics of dysfunctional cilia, with an aim to provide a basis for early identification of such diseases.
Cilia/genetics* ; Genetic Testing ; Humans ; Kartagener Syndrome/genetics* ; Sensitivity and Specificity

Primary ciliary dyskinesia (PCD) is a hereditary disease characterized by airway mucociliary clearance dysfunction. The estimated prevalence of PCD is 1꞉10 000 to 1꞉20 000. The main respiratory manifestations in children are cough, expectoration, chronic rhinitis, sinusitis, and chronic otitis media, while the most common symptoms in adults are chronic sinusitis, bronchiectasis, and infertility. About 50% of patients with certain PCD-related gene variants are combined with situs inversus, and the incidence of congenital heart disease is also high. The pathogenesis behind PCD is that gene variants cause structural or functional disorders of respiratory cilia and motile cilia of other organs, leading to a series of heterogeneous clinical manifestations, which makes it difficult to identify and diagnose PCD. Combining different disease screening tools and understanding the relationship between genotypes and phenotypes may facilitate early diagnosis and treatment for PCD.
Chronic Disease ; Cilia/pathology* ; Humans ; Kartagener Syndrome/genetics* ; Phenotype ; Sinusitis

Cellular primary cilium, located on the surface of virtually all mammalian cells, is a strictly conserved organelle which regulates cell biological process and maintains cell homeostasis by modulating cell proliferation, differentiation, migration, polarity, signal cascades and other life activities. Some diseases caused by mutations in genes encoding structural proteins or accessory proteins of primary cilia are collectively termed as "ciliopathies", which can occur in embryo, infancy and even adulthood. Ciliopathies not only involve a single organ, but also involve multiple organs and multiple systems, showing variable symptoms and overlapping symptoms. This review mainly summarizes the effects of ciliopathy-associated gene mutations on bone, tooth, skin, liver and bile duct, kidney, brain, retina, heart and other organs, uncovers their molecular mechanisms and provides some novel insights into therapy of ciliopathies.
Adult ; Animals ; Cilia ; Ciliopathies/genetics* ; Humans ; Proteins ; Retina ; Signal Transduction

Small GTPases are key molecular switches that bind and hydrolyze GTP in diverse membrane- and cytoskeleton-related cellular processes. Recently, mounting evidences have highlighted the role of various small GTPases, including the members in Arf/Arl, Rab, and Ran subfamilies, in cilia formation and function. Once overlooked as an evolutionary vestige, the primary cilium has attracted more and more attention in last decade because of its role in sensing various extracellular signals and the association between cilia dysfunction and a wide spectrum of human diseases, now called ciliopathies. Here we review recent advances about the function of small GTPases in the context of cilia, and the correlation between the functional impairment of small GTPases and ciliopathies. Understanding of these cellular processes is of fundamental importance for broadening our view of cilia development and function in normal and pathological states and for providing valuable insights into the role of various small GTPases in disease processes, and their potential as therapeutic targets.
Animals ; Cilia ; enzymology ; genetics ; metabolism ; GTP Phosphohydrolases ; metabolism ; Humans

Neurofibromatosis (NF) is a genetic disease in which the lungs are rarely involved. However, in NF cases with lung involvement, chest computed tomography may show bilateral basal reticulations, apical bullae, and cysts without bronchiectasis. Herein, we report a patient diagnosed with NF on the basis of the results of genetic testing who presented with early-onset wet cough and bronchiectasis. Considering the differential diagnosis of bronchiectasis combined with his early-onset wet cough, sinusitis, and sperm quality decline, we considered the possibility of primary ciliary dyskinesia (PCD). Further electron microscopy analysis of cilia and identification of homozygous mutations in the RSPH4A gene confirmed the diagnosis of PCD. Therefore, for patients with NF, when an image change exists in the lungs that does not correspond to NF, the possibility of other diagnoses, including PCD, must be considered.
Cilia ; Humans ; Kartagener Syndrome/genetics* ; Microscopy, Electron ; Mutation ; Neurofibromatosis 1/genetics*

The primary cilium of renal epithelia acts as a transducer of extracellular stimuli. Polycystin (PC)1 is the protein encoded by the PKD1 gene that is responsible for the most common and severe form of autosomal dominant polycystic kidney disease (ADPKD). PC1 forms a complex with PC2 via their respective carboxy-terminal tails. Both proteins are expressed in the primary cilia. Mutations in either gene affect the normal architecture of renal tubules, giving rise to ADPKD. PC1 has been proposed as a receptor that modulates calcium signals via the PC2 channel protein. The effect of PC1 dosage has been described as the rate-limiting modulator of cystic disease. Reduced levels of PC1 or disruption of the balance in PC1/PC2 level can lead to the clinical features of ADPKD, without complete inactivation. Recent data show that ADPKD resulting from inactivation of polycystins can be markedly slowed if structurally intact cilia are also disrupted at the same time. Despite the fact that no single model or mechanism from these has been able to describe exclusively the pathogenesis of cystic kidney disease, these findings suggest the existence of a novel cilia-dependent, cyst-promoting pathway that is normally repressed by polycystin function. The results enable us to rethink our current understanding of genetics and cilia signaling pathways of ADPKD.
Calcium ; Cilia* ; Genetics ; Kidney Diseases, Cystic ; Polycystic Kidney, Autosomal Dominant* ; Transducers ; TRPP Cation Channels*

Primary ciliary dyskinesia (PCD) is a congenital, motile ciliopathy with pleiotropic symptoms. Although nearly 50 causative genes have been identified, they only account for approximately 70% of definitive PCD cases. Dynein axonemal heavy chain 10 (DNAH10) encodes a subunit of the inner arm dynein heavy chain in motile cilia and sperm flagella. Based on the common axoneme structure of motile cilia and sperm flagella, DNAH10 variants are likely to cause PCD. Using exome sequencing, we identified a novel DNAH10 homozygous variant (c.589C > T, p.R197W) in a patient with PCD from a consanguineous family. The patient manifested sinusitis, bronchiectasis, situs inversus, and asthenoteratozoospermia. Immunostaining analysis showed the absence of DNAH10 and DNALI1 in the respiratory cilia, and transmission electron microscopy revealed strikingly disordered axoneme 9+2 architecture and inner dynein arm defects in the respiratory cilia and sperm flagella. Subsequently, animal models of Dnah10-knockin mice harboring missense variants and Dnah10-knockout mice recapitulated the phenotypes of PCD, including chronic respiratory infection, male infertility, and hydrocephalus. To the best of our knowledge, this study is the first to report DNAH10 deficiency related to PCD in human and mouse models, which suggests that DNAH10 recessive mutation is causative of PCD.
Humans ; Male ; Animals ; Mice ; Semen/metabolism* ; Dyneins/metabolism* ; Cilia/metabolism* ; Mutation ; Ciliary Motility Disorders/genetics*

In growing children, growth plate cartilage has limited self-repair ability upon fracture injury always leading to limb growth arrest. Interestingly, one type of fracture injuries within the growth plate achieve amazing self-healing, however, the mechanism is unclear. Using this type of fracture mouse model, we discovered the activation of Hedgehog (Hh) signaling in the injured growth plate, which could activate chondrocytes in growth plate and promote cartilage repair. Primary cilia are the central transduction mediator of Hh signaling. Notably, ciliary Hh-Smo-Gli signaling pathways were enriched in the growth plate during development. Moreover, chondrocytes in resting and proliferating zone were dynamically ciliated during growth plate repair. Furthermore, conditional deletion of the ciliary core gene Ift140 in cartilage disrupted cilia-mediated Hh signaling in growth plate. More importantly, activating ciliary Hh signaling by Smoothened agonist (SAG) significantly accelerated growth plate repair after injury. In sum, primary cilia mediate Hh signaling induced the activation of stem/progenitor chondrocytes and growth plate repair after fracture injury.
Mice ; Animals ; Hedgehog Proteins/genetics* ; Receptors, G-Protein-Coupled/metabolism* ; Cilia/metabolism* ; Cartilage/metabolism* ; Regeneration

OBJECTIVETo examine the important roles of microRNAs (miRNAs) in regulating amphid structure and function, we performed a computational analysis for the genetic loci required for the sensory perception and their possibly corresponding miRNAs in C. elegans.

METHODSTotal 55 genetic loci required for the amphid structure and function were selected. Sequence alignment was combined with E value evaluation to investigate and identify the possible corresponding miRNAs.

RESULTSTotal 30 genes among the 55 genetic loci selected have their possible corresponding regulatory miRNA (s), and identified genes participate in the regulation of almost all aspects of amphid structure and function. In addition, our data suggest that both the amphid structure and the amphid functions might be regulated by a series of network signaling pathways. Moreover, the distribution of miRNAs along the 3' untranslated region (UTR) of these 30 genes exhibits different patterns.

CONCLUSIONWe present the possible miRNA-mediated signaling pathways involved in the regulation of chemosensation and thermosensation by controlling the corresponding sensory neuron and interneuron functions. Our work will be useful for better understanding of the miRNA-mediated control of the chemotaxis and thermotaxis in C. elegans.

Animals ; Caenorhabditis elegans ; embryology ; genetics ; Caenorhabditis elegans Proteins ; biosynthesis ; genetics ; Cilia ; genetics ; Computational Biology ; methods ; Gene Expression Regulation, Developmental ; genetics ; Genome ; genetics ; MicroRNAs ; genetics ; Models, Genetic ; Nervous System ; embryology ; metabolism ; Neurons, Afferent ; metabolism ; Sensation ; genetics ; Signal Transduction ; genetics

OBJECTIVETo investigate the clinical features, diagnosis and treatment of primary ciliary dyskinesia (PCD).

METHODSThree cases of PCD received endoscopic sinus surgery and were followed up for life quality and recovery. Among these 3 cases, two were twin brothers and the other girl was twin born with a healthy brother. The mucosa of inferior turbinate was extracted prior to the operation without narcotic and decongestant. The ultrastructure of mucosal cilia was detected with electron microscope. Nine exons of gene DNAH5 and chromosome in one case and her fraternal twin were evaluated.

RESULTSNasal and sinus CT imaging of the 3 cases showed chronic pansinusitis (1 case accompanied with situs inversus according with the diagnosis of Kartagener syndrome). The nasal polyp was resected, and the sinuses were opened. The twin brothers received the adenoidectomy. All patients felt nasal ventilation improved while the surgical field still covered with thick discharges during follow-up for 2 - 4 years. Ciliary ultrastructures of the three cases showed lateral dynein absent, the sequence of 9 exons of DNAH5 and chromosome presented no change in the fraternal twins.

CONCLUSIONSSurgery could improve the symptoms of sinusitis in PCD. Change of ciliary ultrastructure was an important indication of its pathological changes and molecular biology evaluation needs further study.

Axonemal Dyneins ; metabolism ; Child ; Cilia ; ultrastructure ; Exons ; Female ; Humans ; Kartagener Syndrome ; diagnosis ; genetics ; pathology ; Male ; Sinusitis ; diagnosis ; etiology ; genetics ; Young Adult