Partial AZF deletions including single AZF Y genes can cause the same testicular pathology as the corresponding complete deletion (e.g., DDX3Y gene deletions in AZFa), or might not be associated with male infertility at all (e.g., some BPY2, CDY1, DAZ gene deletions in AZFc).
A total of 11 patients with sertoli cell-only syndrome (SCOS) and 5 oligospermic patients with gr/gr subdeletions also have DAZ1/DAZ2 genes deleted indicating that deletions of DAZ genes contributed differently to damage to spermatogenic process.
Patients with complete Sertoli cell-only syndrome (SCOS) did not exhibit RBMY1, DAZ and TSPY gene expression, however, we detected very low expression of DDX3Y transcript.
Patients with Sertoli cell-only syndrome had additional microdeletions in regions distal to DAZ (Deleted in Azoospermia), although DAZ deletion was observed in seven of the eight affected patients.
Deletions in the AZFc region involving the DAZ gene were the most frequent finding and they were more often observed in severe hypospermatogenesis than in Sertoli cell-only syndrome, suggesting that deletions of this region are not sufficient to cause complete loss of the spermatogenic line.