Complete deletion of the AZFb interval from the Y chromosome in an oligozoospermic man
Authors: Longepied, Guy; Saut, Noemie; Aknin-Seifer, Isabelle; Levy, Rachel; Frances, Anne-Marie; Metzler-Guillemain, Catherine; Guichaoua, Marie-Roberte; Mitchell, Michael J.
Source: Human Reproduction, Volume 25, Number 10, 18 October 2010 , pp. 2655-2663(9)
Publisher: Oxford University Press
Deletion of the entire AZFb interval from the Y chromosome is strictly associated with azoospermia arising from maturation arrest during meiosis. Here, we describe the exceptional case of an oligozoospermic man, 13-1217, with an AZFb c (P5/distal-P1) deletion. Through the characterization of this patient, and two AZFb (P5/proximal-P1) patients with maturation arrest, we have explored three possible explanations for his exceptionally progressive spermatogenesis.
METHODS AND RESULTS
We have determined the precise breakpoints of the deletion in 13-1217, and shown that 13-1217 is deleted for more AZFb material than one of the AZFb-deleted men (13-5349). Immunocytochemical analysis of spermatocytes with an antibody against a synaptonemal complex component indicates synapsis to be largely unaffected in 13-1217, in contrast to 13-5349 where extended asynapsis is frequent. Using PCR-based analyses of RNA and DNA from the same testicular biopsy, we show that 13-1217 expresses post-meiotic germ cell markers in the absence of genomic DNA and transcripts from the AZFb and AZFc intervals. We have determined the Y chromosome haplogroup of 13-1217 to be HgL-M185.
Our results indicate that the post-meiotic spermatogenesis in 13-1217 is not a consequence of mosaicism or retention of a key AZFb gene. On the contrary, since the Hg-L Y chromosome carried by 13-1217 is uncommon in Western Europe, a Y-linked modifier locus remains a possible explanation for the oligozoospermia observed in patient 13-1217. Further cases must now be studied to understand how germ cells complete spermatogenesis in the absence of the AZFb interval.
Document Type: Research Article
Publication date: 18 October 2010
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