title: Assessment of the frequency of sperm annulus defects in a large cohort of patients presenting asthenozoospermia.
abstract: BACKGROUND
  The annulus is a ring-shaped structure located beneath the plasma membrane that connects the midpiece and the principal piece of mammalian sperm flagellum. It has been suggested that the annulus acts as a morphological organizer, guiding flagellum assembly during spermiogenesis, and as a diffusion barrier, confining proteins to distinct compartments of the flagellum in mature sperm. Previous studies on small cohorts of patients have attempted to correlate annulus defects with the occurrence of human asthenozoospermia. An absence of the annulus has been shown to be frequently associated with asthenozoospermia.
  
  
  RESULTS
  We tried to obtain a more precise estimate of the frequency of annulus defects, by screening a large cohort of 254 men presenting asthenozoospermia (mean progressive motility of 24 %) by the immunodetection of SLC26A8, a transmembrane protein that has been shown to be specifically localized to the annulus. By contrast to previous reports, our results indicate that annulus defects are associated with asthenozoospermia in only 1.2 % of cases.
  
  
  CONCLUSIONS
  We conclude that defects or an absence of the annulus are not frequently associated with asthenozoospermia. The use of annulus defects as a diagnostic endpoint in patients is therefore not appropriate.
authors.affiliation: INSERM U1016, Institut Cochin, Paris, 75014 France ; CNRS UMR8104, Paris, 75014 France ; Sorbonne Paris Cité, Faculté de Médecine, Université Paris Descartes, Paris, 75014 France.
authors.forename: Thassadite
authors.initials: T
authors.lastname: Dirami
authors.affiliation: INSERM U1016, Institut Cochin, Paris, 75014 France ; CNRS UMR8104, Paris, 75014 France ; Sorbonne Paris Cité, Faculté de Médecine, Université Paris Descartes, Paris, 75014 France.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Rode
authors.affiliation: INSERM U1016, Institut Cochin, Paris, 75014 France ; CNRS UMR8104, Paris, 75014 France ; Sorbonne Paris Cité, Faculté de Médecine, Université Paris Descartes, Paris, 75014 France ; Assistance Publique-Hôpitaux de Paris, GH Cochin Broca Hôtel Dieu, Laboratoire d'Histologie Embryologie - Biologie de la Reproduction, Paris, 75014 France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Wolf
authors.affiliation: INSERM U1016, Institut Cochin, Paris, 75014 France ; CNRS UMR8104, Paris, 75014 France ; Sorbonne Paris Cité, Faculté de Médecine, Université Paris Descartes, Paris, 75014 France.
authors.forename: Gérard
authors.initials: G
authors.lastname: Gacon
authors.affiliation: Sorbonne Paris Cité, Faculté de Médecine, Université Paris Descartes, Paris, 75014 France ; Assistance Publique-Hôpitaux de Paris, GH Cochin Broca Hôtel Dieu, Laboratoire d'Histologie Embryologie - Biologie de la Reproduction, Paris, 75014 France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Dulioust
authors.affiliation: INSERM U1016, Institut Cochin, Paris, 75014 France ; CNRS UMR8104, Paris, 75014 France ; Sorbonne Paris Cité, Faculté de Médecine, Université Paris Descartes, Paris, 75014 France ; Department of Genetics, Development and Reproduction, Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Descartes, 24 rue du faubourg Saint Jacques, Paris, 75014 France.
authors.forename: Aminata
authors.initials: A
authors.lastname: Touré
keywords: Annulus; Asthenozoospermia; Flagellum; Motility; SLC26A8; Sperm