RESUMO
BACKGROUND: Chromosomal abnormalities are confirmed as one of the frequent causes of male infertility. The microdeletion of the azoospermia factor (AZF) region in the Y chromosome was discovered as another frequent genetic cause associated with male infertility. The aim of this study was to evaluate the frequency and type of chromosomal abnormalities and Y chromosome microdeletions in Korean infertile men. METHODS: A total of 846 infertile men with azoospermia and severe oligozoospermia were included for genetic screening. Cytogenetic analyses using G-banding and screening for Y chromosome microdeletions by multiplex PCR for AZF genes were performed. RESULTS: Chromosomal abnormalities were detected in 112 infertile men (13.2%). Of these, Klinefelter's syndrome was the most common (55.4%, 62/112), followed by balanced translocation including translocation between sex chromosome and autosome (14.3%), Yq deletion (13.4%), X/XY mosaicism with Yq deletion (12.5%), and XX male (4.5%). The overall prevalence of Y chromosome microdeletions was 9.2% (78/846). Most microdeletions were in the AZFc region (51.3%) with a low incidence in AZFa (7.7 %) and AZFb (6.4 %). Combined deletions involving the AZFbc and AZFabc regions were detected in 26.9 % and 7.7 % of men, respectively. Among the infertile men with Y chromosome microdeletions, the incidence of chromosomal abnormality was 25.6% (20/78). CONCLUSIONS: There was a high incidence (20.1%) of chromosomal abnormalities and Y chromosome microdeletions in Korean infertile men. These findings strongly suggest that genetic screening for chromosomal abnormalities and Y chromosome microdeletions should be performed, and genetic counseling should be provided before starting assisted reproductive techniques.