Background: Azoospermia is defined as the absence of sperm in the semen and is divided in two types; obstructive and non-obstructive azoospermia. Non-obstructive azoospermia include approximately 60% of azoospermia patients. Several genetic and environmental factors can be involved in the development of non-obstructive azoospermia. Until now, several genes have been introduced as the causing factor of the azoospermia that are involved in spermatogenesis and testicular development. These genes are located on Y and/or autosome chromosomes .The aim of the present study was to investigate Y chromosome microdeletions and STAG3 gene mutations in Iranian males with non-obstructive azoospermia.

Materials and Methods: In this study, peripheral blood samples were obtained from 122 men with idiopathic non-obstructive azoospermia and 100 Normo-sperm men who had at least one child and DNA was extracted. Samples were investigated for the presence of Y chromosome microdeletions by Multiplex PCR. Then, existence of probable mutations in exon 7 of STAG3 gene was investigated using MSSCP (multi-temperature single-strand conformational polymorphism) method.

Results: 13 patients (10.66%) had Y chromosome microdeletions, but none of the subjects showed mutation in exon 7 of STAG3 gene. The Y chromosome microdeletions were found in none of the control individuals.

Conclusion: The results showed that Y chromosome microdeletions are the most important cause of non-obstructive azoospermia and should be considered as the main candidate for male infertility diagnostic tests. Mutations in the STAG3 gene are not common among non-obstructive azoospermia patients.