Mutations in DNAJB13, Encoding an HSP40 Family Member, Cause Primary Ciliary Dyskinesia and Male Infertility

  • Am J Hum Genet. 2016 Aug 4;99(2):489-500. doi: 10.1016/j.ajhg.2016.06.022.
Elma El Khouri  1 Lucie Thomas  2 Ludovic Jeanson  2 Emilie Bequignon  3 Benoit Vallette  2 Philippe Duquesnoy  2 Guy Montantin  4 Bruno Copin  5 Florence Dastot-Le Moal  5 Sylvain Blanchon  6 Jean François Papon  7 Patrick Lorès  1 Li Yuan  8 Nathalie Collot  4 Sylvie Tissier  4 Catherine Faucon  9 Gérard Gacon  1 Catherine Patrat  10 Jean Philippe Wolf  11 Emmanuel Dulioust  11 Bruno Crestani  12 Estelle Escudier  5 André Coste  3 Marie Legendre  5 Aminata Touré  13 Serge Amselem  5
Affiliations
  • 1. INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France.
  • 2. INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Paris 75012, France.
  • 3. Equipe 13, INSERM UMR S955, Faculté de Médecine, Université Paris Est, Centre National de la Recherche Scientifique ERL7240, Créteil 94000, France; Service d'ORL et de Chirurgie Cervicofaciale, Centre Hospitalier Intercommunal de Créteil & Groupe Hospitalier Henri Mondor-Albert Chenevier, Assistance Publique - Hôpitaux de Paris, Créteil 94000, France.
  • 4. Service de Génétique et d'Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France.
  • 5. INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Paris 75012, France; Service de Génétique et d'Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France.
  • 6. INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Paris 75012, France; Unité de Pneumologie et Allergologie Pédiatrique, Hôpital des Enfants, Centre Hospitalier Universitaire, Toulouse 31300, France.
  • 7. Equipe 13, INSERM UMR S955, Faculté de Médecine, Université Paris Est, Centre National de la Recherche Scientifique ERL7240, Créteil 94000, France; Service d'Oto-Rhino-Laryngologie et de Chirurgie Cervico-Maxillo-Faciale, Hôpital Bicêtre, Assistance Publique - Hôpitaux de Paris, Le Kremlin-Bicêtre 94275, France.
  • 8. Savaid School of Medicine and College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
  • 9. Laboratoire de Microscopie Electronique, Service d'Anatomopathologie, Centre Hospitalier Intercommunal de Créteil, Créteil 94000, France.
  • 10. Service de Biologie de la Reproduction, Hôpital Bichat, Assistance Publique - Hôpitaux de Paris, Université Paris Diderot, Sorbonne Paris Cité, Paris 75018, France.
  • 11. Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France; Laboratoire d'Histologie Embryologie, Biologie de la Reproduction, Groupe Hospitalier Cochin-Broca-Hôtel Dieu, Assistance Publique - Hôpitaux de Paris, Paris 75014, France.
  • 12. Service de Pneumologie A, Hôpital Bichat, Assistance Publique - Hôpitaux de Paris, Paris 75018, France.
  • 13. INSERM U1016, Institut Cochin, Paris 75014, France; Centre National de la Recherche Scientifique UMR8104, Paris 75014, France; Faculté de Médecine, Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France. Electronic address: [email protected].
Abstract

Primary ciliary dyskinesia (PCD) is an autosomal-recessive disease due to functional or ultra-structural defects of motile cilia. Affected individuals display recurrent respiratory-tract infections; most males are infertile as a result of sperm flagellar dysfunction. The great majority of the PCD-associated genes identified so far encode either components of dynein arms (DAs), which are multiprotein-ATPase complexes essential for ciliary motility, or proteins involved in DA assembly. To identify the molecular basis of a PCD phenotype characterized by central complex (CC) defects but normal DA structure, a phenotype found in ∼15% of cases, we performed whole-exome Sequencing in a male individual with PCD and unexplained CC defects. This analysis, combined with whole-genome SNP genotyping, identified a homozygous mutation in DNAJB13 (c.833T>G), a gene encoding a HSP40 co-chaperone whose ortholog in the flagellated alga Chlamydomonas localizes to the radial spokes. In vitro studies showed that this missense substitution (p.Met278Arg), which involves a highly conserved residue of several HSP40 family members, leads to protein instability and triggers proteasomal degradation, a result confirmed by the absence of endogenous DNAJB13 in cilia and sperm from this individual. Subsequent DNAJB13 analyses identified another homozygous mutation in a second family; the study of DNAJB13 transcripts obtained from airway cells showed that this mutation (c.68+1G>C) results in a splicing defect consistent with a loss-of-function mutation. Overall, this study, which establishes mutations in DNAJB13 as a cause of PCD, unveils the key role played by DNAJB13 in the proper formation and function of ciliary and flagellar axonemes in humans.

Keywords
DNAJB13; PCD; central complex; cilia; radial spoke; sperm flagellum.