Objectives　To evaluate the relationship between microdeletion or mutation on the Y chromosome and Chinese patients with idiopathic azoospermia and severe oligozoospermia and to establish a molecular detection method.Methods　Microdeletion or mutation detection at the AZFa (sY84 and USP9Y), AZFb, AZFc/DAZ and SRY regions of the Y chromosome. Seventy-three azoospermia and 28 severe oligozoospermia patients were evaluated using PCR and PCR-SSCP techniques.Results　Twelve of 101 patients (12%) with the AZFc/DAZ microdeletion were found, including 8 with azoospermia (11%) and 4 with severe oligozoospermia (14.3%), and 1 patient had a AZFb and AZFc/DAZ double deletion. No deletions in the AZFa or SRY regions were found. No deletions in AZFa, AZFb, AZFc/DAZ or SRY regions were found in 60 normal men who had produced one or more children.Conclusions　Microdeletion on the Y chromosome, especially at its AZFc/DAZ regions, may be a major cause of azoospermia and severe oligozoospermia leading to male infertility in China. It is recommended that patients have genetic counseling and microdeletion detection on the Y chromosome before intracytoplasmic sperm injection.

泰国少精无精不育男性中Y染色体微缺失和染色体异常的发病率

Aim:To investigate the possible causes of oligozoospermia and azoospermia in infertile Thai men, and to find the frequencies of Y chromosome microdeletions and cytogenetic abnormalities in this group. Methods: From June 2003 to November 2005, 50 azoospermic and 80 oligozoospermic men were enrolled in the study. A detailed history was taken for each man, followed by general and genital examinations. Y chromosome microdeletions were detected by multiplex polymerase chain reaction (PCR) using 11 gene-specific primers that covered all three regions of the azoospermic factor (AZFa, AZFb and AZFc). Fifty men with normal semen analysis were also studied. Karyotyping was done with the standard G- and Q-banding. Serum concentrations of follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL) and testosterone were measured by electrochemiluminescence immunoassays (ECLIA). Results: Azoospermia and oligozoospermia could be explained by previous orchitis in 22.3%, former bilateral cryptorchidism in 19.2%, abnormal karyotypes in 4.6% and Y chromosome microdeletions in 3.8% of the subjects. The most frequent deletions were in the AZFc region (50%), followed by AZFb (33%) and AZFbc (17%).No significant difference was detected in hormonal profiles of infertile men, with or without microdeletions.Conclusion: The frequencies of Y chromosome microdeletions and cytogenetic abnormalities in oligozoospermic and azoospermic Thai men are comparable with similarly infertile men from other Asian and Western countries.