Screening for deletions in interval D16–22 of the Y chromosome in azoospermic and oligozoospermic Japanese men

The genetic basis of infertility remains unclear in a majority of infertile men. In this study, the Y chromosome long arm involving the DAZ (deleted in azoospermia) gene was screened in order to evaluate the occurrence of microdeletion in Japanese infertile men. One hundred and fifty-seven infertile Japanese men with azoospermia and oligozoospermia were analyzed for microdeletions in interval D16–22 of the Y chromosome, using polymerase chain reaction with sequence-tagged site markers. Sixteen sets of oligonucleotide primers were synthesized for the polymerase chain reaction, and Southern blot analysis was also performed. The men were divided into five categories on the basis of sperm concentration: functional azoospermia (A; n = 24), azoospermia caused by obstruction (AO; n = 20), oligozoospermia I (OI, sperm concentration less than 1 × 105/ml; n = 33), oligozoospermia II (OII, sperm concentration less than 1 × 106/ml; n = 30), and oligozoospermia III (OIII, sperm concentration less than 1 × 107/ml; n = 50). Thirty fertile men with a sperm concentration of more than 2 × 107/ml were also analyzed as controls. Microdeletions were identified, in 12 (7.6%) of the 157 infertile men, as follows: 1 man in category A, 1 in category AO, 5 in category OI, 4 in category OII, and 1 in category OIII. No deletion was identified in the fertile men. One common region around sY240 was identified in 11 of the infertile men with microdeletions. This locus may contain specific genes for spermatogenesis. The sperm concentration in the ten oligozoospermic men with microdeletions was below 1 × 106/ml. There were no correlations between the severity of spermatogenic defects and the extent of the microdeletions. These results suggested that genes in the interval D16–22 of the Y chromosome might have important roles in spermatogenesis.