RESUMEN
<p><b>OBJECTIVE</b>To investigate Y chromosome microdeletions in severe oligospermia men with varicocele.</p><p><b>METHODS</b>We randomly selected 100 cases of severe oligospermia with left varicocele (sperm concentration <5 x 10(6)/ml, group 1), 100 cases of mild oligospermia with left varicocele (sperm concentration 10 -20 x 10(6)/ml, group 2), 100 cases of idiopathic infertility with severe oligospermia (group 3), 100 cases of idiopathic infertility with moderate oligospermia (group 4) and 30 normal fertile men as controls (group 5). We used polymerase chain reaction (PCR) technology to screen 9 sequence tagged sites (STS) of the AZF a, b and c regions and detect Y chromosome microdeletions.</p><p><b>RESULTS</b>AZF microdeletions were found in 19 patients in group 1 (19%) and 11 in group 3 (11%), with a higher rate in the former than in the latter, but not in the other three groups.</p><p><b>CONCLUSION</b>Screening of Y chromosome microdeletions should be performed before the treatment of severe spermatogenesis with varicocele.</p>