ABSTRACT
<p><b>Objective</b>To investigate the 5'-flanking regulatory sequence methylation status of the Boule gene in the testis tissue of infertile men with Sertoli cell-only syndrome (SCOS).</p><p><b>METHODS</b>We collected biopsy samples of the testis tissue from 12 men with obstructive azoospermia (the control group) and 15 cases of SCOS, all without varicocele, cryptorchidism, or infectious disease. We extracted genomic DNA from the testis tissue of the SCOS patients, analyzed the characteristics of the 5'-flanking regulatory sequence of the Boule gene using the bioinformatics method, and detected the methylation status of the Boule gene by sodium bisulfite sequencing.</p><p><b>RESULTS</b>A CpG island was observed in the 5'-flanking regulation region of the Boule gene. The methylation level of the Boule gene was remarkably higher in the SCOS group than in the obstructive azoospermia controls (61.4% vs 21.7%, P<0.01), with significant differences in the methylation levels of 14 CpG sites, namely, －58 bp, －50 bp, －48 bp, －38 bp, －28 bp, －24 bp, －20 bp, －15 bp, －1 bp, +5 bp, +8 bp, +15 bp, +29 bp, and +58 bp.</p><p><b>CONCLUSIONS</b>The methylation level of the Boule gene is significantly higher in the SCOS patients than in the obstructive azoospermia males, which suggests that the changes in Boule methylation may be associated with spermatogenic dysfunction.</p>