Purpose: To investigate the effect of the deleted in azoospermia (DAZ) copy cluster deletion on spermatogenesis in the South Chinese population.
Methods: In this study, the prevalence and characteristics of different DAZ copy cluster deletions and their association with spermatogenic failure were analyzed. A total of 186 infertile men with different spermatogenic impairments and 190 normozoospermic fertile men were studied. Three DAZ-specific single nucleotide variant loci and seven AZFc-specific sequence-tagged sites were examined using polymerase chain reaction (PCR)-restriction fragment length polymorphism and routine PCR.
Results: Gr/gr deletions were observed in a total of 9 of the 190 normozoospermic fertile men, and 11 gr/gr deletions were found in 186 infertile men. In addition, 3 b2/b3 deletions were identified in the infertile, but not in the fertile men. DAZ-SNV loci analysis revealed 4 DAZ copies that had 8 gr/gr-DAZ3/DAZ4 deletions and 1 gr/gr-DAZ1/DAZ2 deletion in the fertile men (8/190 vs. 1/190, p = 0.037). Analysis of DAZ deletion copies in infertile men revealed 10 gr/gr-DAZ1/DAZ2 deletions, 1 gr/gr-DAZ3/DAZ4 deletion (10/186 vs. 1/186, p = 0.011) and 3 b2/b3-DAZ1/DAZ2 deletions (13/186 vs. 1/186, p = 0.002).
Conclusions: Analysis of DAZ gene copies in AZFc microdeletions suggests that the contribution of the different deletions to male infertility varies. Removing DAZ1/DAZ2 seems to be associated with spermatogenic impairment, whereas removing DAZ3/DAZ4 seems to have little or no effect on fertility in the South Chinese population.