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 i n azoospermia) gene was screened in order to evaluate the occurrence of mic rodeletion in Japanese infertile men. One hundred and fifty-seven infertile Japanese men with azoospermia and oligozoospermia were analyzed for microd eletions in interval D16-22 of the Y chromosome, using polymerase chain rea ction with sequence-tagged site markers. Sixteen sets of oligonucleotide pr imers 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), azoos permia caused by obstruction (AO; n = 20), oligozoospermia I (OI, sperm con centration less than 1 x 10(5)/ml; n = 33), oligozoospermia II (OII, sperm concentration less than 1 x 10(6)/ml; n = 30), and oligozoospermia III (OII I, sperm concentration less than 1 X 10(7)/ml; n = 50). Thirty fertile men with a sperm concentration of more than 2 X 10(7)/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 th e fertile men. One common region around sY240 was identified in II of the i nfertile men with microdeletions. This locus may contain specific genes for spermatogenesis. The sperm concentration in the ten oligozoospermic men wi th microdeletions was below 1 X 10(6)/ml. There were no correlations betwee n the severity of spermatogenic defects and the extent of the microdeletion s. These results suggested that genes in the interval D16-22 of the Y chrom osome might have important roles in spermatogenesis.