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Cellular & Molecular Biology Letters

Open Access

Is a genetic defect in Fkbp6 a common cause of azoospermia in humans?

  • Toshinobu Miyamato1Email author,
  • Hisashi Sato1,
  • Leah Yogev2,
  • Sandra Kleiman2,
  • Mikio Namiki3,
  • Eitetsu Koh3,
  • Naoko Sakugawa1,
  • Hiroaki Hayashi1,
  • Mutsuo Ishikawa1,
  • Dolores J. Lamb4 and
  • Kazuo Sengoku1
Cellular & Molecular Biology LettersAn International Journal200611:43

Received: 16 January 2006

Accepted: 28 June 2006

Published: 14 September 2006


FK506-binding protein 6 (Fkbp6) is a member of a gene family containing a prolyl isomerase/FK506-binding domain and tetratricopeptide protein-protein interaction domains. Recently, the targeted inactivation of Fkbp6 in mice has been observed to result in aspermic males and the absence of normal pachytene spermatocytes. The loss of Fkbp6 results in abnormal pairing and a misalignment of the homologous chromosomes, and in non-homologous partner switches and autosynapsis of the X chromosome cores in meiotic spermatocytes. In this study, we analyzed whether human FKBP6 gene defects might be associated with human azoospermia. We performed a mutation analysis in all the coding regions of the human FKBP6 gene in 19 patients with azoospermia resulting from meiotic arrest. The expression of the human FKBP6 gene was specific to the testis, and a novel polymorphism site, 245C → G (Y60X) could be found in exon 3. Our findings suggest that the human FKBP6 gene might be imprinted in the testis based on an analysis using two polymorphism sites.

Key words

Azoospermia FKBP6 Genomic imprintingMeiosisPolymorphism