Abstract
Primary ciliary dyskinesia (PCD) is a genetically heterogeneous chronic destructive airway disease. PCD is traditionally diagnosed by nasal nitric oxide measurement, analysis of ciliary beating, transmission electron microscopy (TEM), and/or genetic testing. In most genetic PCD variants, laterality defects can occur. However, it is difficult to establish a diagnosis in individuals with PCD and central pair (CP) defects, and alternative strategies are required because of very subtle ciliary beating abnormalities, a normal ciliary ultrastructure, and normal situs composition. Mutations in HYDIN are known to cause CP defects, but the genetic analysis of HYDIN variants is confounded by the pseudogene HYDIN2, which is almost identical in terms of intron/exon structure. We have previously shown that several types of PCD can be diagnosed via immunofluorescence (IF) microscopy analyses. Here, using IF microscopy, we demonstrated that in individuals with PCD and CP defects, the CP-associated protein SPEF2 is absent inHYDIN-mutant cells, revealing its dependence on functional HYDIN. Next, we performed IF analyses of SPEF2 in respiratory cells from 189 individuals with suspected PCD and situs solitus. Forty-one of the 189 individuals had undetectable SPEF2 and were subjected to a genetic analysis, which revealed one novel loss-of-function mutation in SPEF2 and three reported and 13 novel HYDIN mutations in 15 individuals. The remaining 25 individuals are good candidates for new, as-yet uncharacterized PCD variants that affect the CP apparatus. SPEF2 mutations have been associated with male infertility but have not previously been identified to cause PCD. We identified a mutation of SPEF2 that is causative for PCD with a CP defect. We conclude that SPEF2 IF analyses can facilitate the detection of CP defects and evaluation of the pathogenicity of HYDIN variants, thus aiding the molecular diagnosis of CP defects.
| Original language | English |
|---|---|
| Pages (from-to) | 382-396 |
| Number of pages | 15 |
| Journal | American Journal of Respiratory Cell and Molecular Biology |
| Volume | 62 |
| Issue number | 3 |
| DOIs | |
| State | Published - 1 Mar 2020 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2020 by the American Thoracic Society.
Funding
Supported by the Deutsche Forschungsgemeinschaft (Om6/7, Om6/8, OM6/10, OM6-11, OM6/14, OL450/1, HJ7/1-1, and KFO 326 [H. Omran]), the Interdisziplinäres Zentrum fur Klinische Forschung Muenster (Om2/009/12 and Om2/015/16), Better Experimental Screening and Treatment for Primary Ciliary Dyskinesia (BESTCILIA; grant agreement number 305404), the Schroeder Stiftung, Kindness for Kids, Eva Luise Köhler Forschungspreis, Care-for-Rare Foundation, and the Innovative Medizinische Forschung (LO 1 2 15 17). The clinical and diagnostic workup in the Danish PCD Centre was partially supported by BESTCILIA (grant agreement number 305404) and the Children’s Lung Foundation. Several authors of this publication are members of the European Reference Network for Rare Respiratory Diseases (ERN-LUNG)—Project ID No. 739546.
| Funders | Funder number |
|---|---|
| Better Experimental Screening and Treatment for Primary Ciliary Dyskinesia | 305404 |
| Children’s Lung Foundation | |
| Innovative Medizinische Forschung | LO 1 2 15 17 |
| Schroeder Stiftung | |
| Care-for-Rare Foundation | |
| Deutsche Forschungsgemeinschaft | OM6-11, OM6/10, KFO 326, OL450/1, Om6/8, Om6/7, HJ7/1-1, OM6/14 |
| Eva Luise und Horst Köhler Stiftung | |
| Interdisziplinäres Zentrum für Klinische Forschung, Universitätsklinikum Würzburg | Om2/009/12, Om2/015/16 |
Keywords
- Cilia
- HYDIN2
- Immunofluorescence microscopy analysis
- Situs solitus
- Test sensitivity and specificity