Deletion and Testicular Expression of DAZ (Deleted in Azoospermia) Gene in Patients with Non-Obstructive Azoospermia

Abstract

Background: Deletions of the DAZ (deleted in azoospermia) genes within the human Y chromosome's AZFc region are the most common cause of spermatogenesis failure. These deletions are usuallyassessed by analyses of genomic DNA ex­tracted from peripheralleukocytes. DAZ genes are expressed in male germ cells. In this prospective study, we investigated DAZ expression and deletion in 102 consecutive infertile men presenting with non-obstructive azoospermia in Avesina Re­search Institute, Tehran, Iran during 2005-6.
Methods: In this prospective study, we extracted genomic DNA from peripheral bloodleukocytes for detection of DAZ dele­tions and testicular biopsies for histopathological assessment and analyses of DAZ expression level by reverse transcrip­tion polymerase chain reaction. DAZ levels were normalized to expression of the housekeeping Phosphoglu-comu­tase 1 gene.
Results:  In four out of 102 patients (3.9%), we found DAZ deletion. DAZ expression was observed in 60 (61.2%) of 98 other patients. Expression was not detected in patients with Sertoli cell-only syndrome, but observed in 37 of 40 (92.5%) pa­tients with maturation arrest and 20 of 26 (76.9%) with hypospermatogenesis.
Conclusion: The absence of DAZ expression could result in quantitative reduction of germ cells and might be observed de­spiteof normal genomic DNA constitution. We recommend to check DAZ testicular expression and genomic DNA deletion, in non-obstructive azoospermia. This is more recommended to avoid transmission of genetic abnormalities which might lead to infertility in male offspring, when assisted reproductive techniques (ART) are  performed.