OBJECTIVETo 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.

METHODSSemen 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.

RESULTSSixty-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.

CONCLUSIONIn 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.