ABSTRACT
<p><b>OBJECTIVE</b>To explore the incidence and location of Y chromosome microdeletions in Chinese azoospermia and severe oligozoospermia, as well as the relationship between the deletion region and testicular phenotype.</p><p><b>METHODS</b>Semen samples or blood samples were collected from 664 Chinese patients (584 with azoospermia and 80 with severe oligozoospermia). DNA was extracted by incubating cells with a lysis buffer containing polymerase chain reaction (PCR) buffer and proteinase K, and was assayed for deletion of 15 sequence tagged sites (including 6 loci recommended by European Academy of Andrology and European Molecular Genetics Quality Network (EAA/EMQN) distributed in AZFa, AZFb and AZFc by 4 multiplex PCRs. The histological phenotypes of testes of some azoospermic patients harboring Y chromosome microdeletion were studied by fine needle aspiration.</p><p><b>RESULTS</b>Sixty-six (11.3%) cases of microdeletions were found in the 584 patients with azoospermia, and deletions of AZFc region are the leading group (72.7% of all deletions), followed by AZFbc (13.6%), AZFabc (6.1%), AZFb (4.5%) and AZFa (3.0%). In the 80 men with severe oligozoospermia, 10 (12.5%) cases of AZFc microdeletions were detected. While azoospermia (n=19) with AZFc region deletion showed variable testicular phenotype, deletions of AZFb+c and AZFa+b+c (n=7) resulted in severe impaired spermatogenesis characterized by Sertoli cell only syndrome and spermatogenic arrest at spermatogonia.</p><p><b>CONCLUSION</b>In the Chinese men with azoospermia and severe oligozoospermia, the incidence of Y chromosome microdeletions and the frequency of the deletions of the three AZF regions are similar to those described previously in other populations. Massive deletions of AZFb+c and AZFa+b+c impair spermatogenesis severely.</p>