Complete deletion of the AZFb interval from the Y chromosome in an oligozoospermic man.
BACKGROUND
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.


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.


CONCLUSIONS
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.
Longepied
Guy
G
Inserm UMR_S 910, Faculté de Médecine Timone, Université de La Méditerranée, 27 bd Jean Moulin, Marseille 13385, France.
Saut
Noemie
N
Aknin-Seifer
Isabelle
I
Levy
Rachel
R
Frances
Anne-Marie
AM
Metzler-Guillemain
Catherine
C
Guichaoua
Marie-Roberte
MR
Mitchell
Michael J
MJ
D000328:Adult; D000368:Aged; D053713:Azoospermia / Q000235:genetics*; D001483:Base Sequence; D023902:Chromosome Pairing / Q000235:genetics; D041322:Chromosomes, Human, Y / Q000235:genetics*; D006801:Humans; D008297:Male; D008540:Meiosis / Q000235:genetics; D008969:Molecular Sequence Data; D009845:Oligospermia / Q000235:genetics*; D017384:Sequence Deletion; D013090:Spermatocytes / Q000473:pathology; D013091:Spermatogenesis / Q000235:genetics