ABSTRACT
Primary ciliary dyskinesia (PCD) is a highly heterogeneous recessive inherited disorder. FAP54, the homolog of CFAP54 in Chlamydomonas reinhardtii, was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella. A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes. Through whole-exome sequencing, compound heterozygous variants c.2649_2657delinC (p. E883Dfs*47) and c.7312_7313insCGCAGGCTGAATTCTTGG (p. T2438delinsTQAEFLA) in a new suspected PCD-relevant gene, CFAP54, were identified in an individual with PCD. Two missense variants, c.4112A>C (p. E1371A) and c.6559C>T (p. P2187S), in CFAP54 were detected in another unrelated patient. In this study, a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression. In addition, a CFAP54 in-frame variant knock-in mouse model was established, which recapitulated the typical symptoms of PCD, including hydrocephalus, infertility, and mucus accumulation in nasal sinuses. Correspondingly, two missense variants were deleterious, with a dramatic reduction in mRNA abundance from bronchial tissue and sperm. The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene. This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.
Subject(s)
Mice , Animals , Humans , Male , Kartagener Syndrome/metabolism , Cilia/metabolism , Semen , Genetic Testing , RNA, Messenger , MutationABSTRACT
The diagnosis of primary ciliary dyskinesia (PCD) is complex and requires high clinical suspicion. The findings in the diagnostic images are nonspecific and can be seen in other conditions of the airway. In this review, we will describe the findings of PCD in chest radiography and computed tomography, with emphasis on some of the characteristics that differentiate it from cystic fibrosis and we will review the role of CT in the monitoring of changes of the PCD, since the CT findings correlate very well with the structural changes that occur in the course of PCD, especially bronchiectasis. However, using serial CTs should be decided on a case-by-case basis to avoid unnecessary radiation because they are pediatric patients.
El diagnóstico de la Discinesia ciliar primaria (DCP) es complejo y requiere alta sospecha clínica. Los hallazgos en la imágenes diagnósticas son inespecíficos y se pueden ver en otras afecciones de la vía aérea. En esta revisión describiremos los hallazgos de la DCP en Radiología simple y en Tomografía computada (TC), con énfasis en algunas de las características que permiten diferenciarla de la Fibrosis quística (FQ) y revisaremos el rol de la TC en la monitorización de la DCP ya que los hallazgos en la TC se correlacionan muy bien con los cambios estructurales que ocurren en el curso de la DCP, en especial las bronquiectasias. Sin embargo usar TC seriadas se debe decidir caso por caso para evitar la radiación innecesaria por ser pacientes pediátricos.