Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 38 3 2009 09 15 17 23 M Aarabi Dept. of Reproductive Genetics and Biotechnology, Reproductive Biotechnology Research Center, Avesin K Saliminejad Dept. of Reproductive Genetics and Biotechnology, Reproductive Biotechnology Research Center, Avesin MR Sadeghi Dept. of Reproductive Genetics and Biotechnology, Reproductive Biotechnology Research Center, Avesin H Soltanghoraee Avesina Infertility Clinic, Avesina Research Institute, Tehran, Iran N Amirjannati Avesina Infertility Clinic, Avesina Research Institute, Tehran, Iran MH Modarressi 2015 10 03 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 usually assessed by analyses of genomic DNA ex­tracted from peripheral leukocytes. 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 blood leukocytes 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 de­spite of 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. https://ijph.tums.ac.ir/index.php/ijph/article/view/3166 https://ijph.tums.ac.ir/index.php/ijph/article/download/3166/2965