deletion and testicular expression of daz (deleted in azoospermia) gene in patients with non-obstructive azoospermia

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.