Biomaterial Database

Pathogenic variants in CLXN encoding the outer dynein arm docking-associated calcium-binding protein calaxin cause primary ciliary dyskinesia. 2023

Rim Hjeij, and Isabella Aprea, and Marco Poeta, and Tabea Nöthe-Menchen, and Diana Bracht, and Johanna Raidt, and Barbara I Honecker, and Gerard W Dougherty, and Heike Olbrich, and Oliver Schwartz, and Ulrike Keller, and Harald Nüsse, and Karin E M Diderich, and Christian Vogelberg, and Francesca Santamaria, and Heymut Omran

Department of General Pediatrics, University Hospital Muenster, Muenster, Germany.

Primary ciliary dyskinesia (PCD) is a heterogeneous disorder that includes respiratory symptoms, laterality defects, and infertility caused by dysfunction of motile cilia. Most PCD-causing variants result in abnormal outer dynein arms (ODAs), which provide the generative force for respiratory ciliary beating and proper mucociliary clearance. In addition to studies in mouse and planaria, clinical exome sequencing and functional analyses in human were performed. In this study, we identified homozygous pathogenic variants in CLXN (EFCAB1/ODAD5) in 3 individuals with laterality defects and respiratory symptoms. Consistently, we found that Clxn is expressed in mice left-right organizer. Transmission electron microscopy depicted ODA defects in distal ciliary axonemes. Immunofluorescence microscopy revealed absence of CLXN from the ciliary axonemes, absence of the ODA components DNAH5, DNAI1, and DNAI2 from the distal axonemes, and mislocalization or absence of DNAH9. In addition, CLXN was undetectable in ciliary axonemes of individuals with defects in the ODA-docking machinery: ODAD1, ODAD2, ODAD3, and ODAD4. Furthermore, SMED-EFCAB1-deficient planaria displayed ciliary dysmotility. Our results revealed that pathogenic variants in CLXN cause PCD with defects in the assembly of distal ODAs in the respiratory cilia. CLXN should be referred to as ODA-docking complex-associated protein ODAD5.

UI	MeSH Term	Description	Entries
D007619	Kartagener Syndrome	An autosomal recessive disorder characterized by a triad of DEXTROCARDIA; INFERTILITY; and SINUSITIS. The syndrome is caused by mutations of DYNEIN genes encoding motility proteins which are components of sperm tails, and CILIA in the respiratory and the reproductive tracts.	Kartagener Triad,Ciliary Dyskinesia, Primary, 1,Ciliary Dyskinesia, Primary, 1, With Or Without Situs Inversus,Dextrocardia, Bronchiectasis, and Sinusitis,Kartagener's Syndrome,Kartagener's Triad,Polynesian Bronchiectasis,Siewert Syndrome,Bronchiectasis, Polynesian,Kartageners Syndrome,Kartageners Triad,Polynesian Bronchiectases,Syndrome, Kartagener,Syndrome, Kartagener's,Syndrome, Siewert
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D002135	Calcium-Binding Proteins	Proteins to which calcium ions are bound. They can act as transport proteins, regulator proteins, or activator proteins. They typically contain EF HAND MOTIFS.	Calcium Binding Protein,Calcium-Binding Protein,Calcium Binding Proteins,Binding Protein, Calcium,Binding Proteins, Calcium,Protein, Calcium Binding,Protein, Calcium-Binding
D002923	Cilia	Populations of thin, motile processes found covering the surface of ciliates (CILIOPHORA) or the free surface of the cells making up ciliated EPITHELIUM. Each cilium arises from a basic granule in the superficial layer of CYTOPLASM. The movement of cilia propels ciliates through the liquid in which they live. The movement of cilia on a ciliated epithelium serves to propel a surface layer of mucus or fluid. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Motile Cilia,Motile Cilium,Nodal Cilia,Nodal Cilium,Primary Cilia,Primary Cilium,Cilium,Cilia, Motile,Cilia, Nodal,Cilia, Primary,Cilium, Motile,Cilium, Nodal,Cilium, Primary
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D051379	Mice	The common name for the genus Mus.	Mice, House,Mus,Mus musculus,Mice, Laboratory,Mouse,Mouse, House,Mouse, Laboratory,Mouse, Swiss,Mus domesticus,Mus musculus domesticus,Swiss Mice,House Mice,House Mouse,Laboratory Mice,Laboratory Mouse,Mice, Swiss,Swiss Mouse,domesticus, Mus musculus
D054468	Axoneme	A bundle of MICROTUBULES and MICROTUBULE-ASSOCIATED PROTEINS forming the core of each CILIUM or FLAGELLUM. In most eukaryotic cilia or flagella, an axoneme shaft has 20 microtubules arranged in nine doublets and two singlets.	Axonemes
D056444	Axonemal Dyneins	Dyneins that are responsible for ciliary and flagellar beating.	Axonemal Dynein,Dynein, Axonemal,Dyneins, Axonemal