Several epidemiological studies have suggested that the incidence of male reproductive organ malformations, including
hypospadias or
cryptorchidism, has increased due to fetal-stage exposure to
environmental pollutants. However, the association of chemical exposure with the expression of target regulatory genes in the tissues of patients has not yet been reported. Because experimental approaches or clinical trials in human studies are limited, especially those using fetal and/or infants, it is difficult to obtain clear physiological evidence of mechanisms underlying male reproductive malformations. Thus, the lack of physiological evidence makes this issue controversial. We analyzed preputial tissues from patients with
hypospadias (n = 23) and
phimosis (n = 16). The atypical
CYP1 family genes,
CYP1A1 and CYP1B1, are potential
biomarkers of environmental chemical exposure. We then compared the expression levels of
CYP1A1 and CYP1B1 between
hypospadias and
phimosis samples by quantitative RT-PCR analysis. The
mRNA expression levels of SRD5A2 and AR also were measured, because the
androgen-related genes involved in the onset of disorders of male reproductive system. A significantly higher CYP1B1 expression level and a lower AR expression level were observed in the
hypospadias groups than in the
phimosis group. Positive correlations (P < 0.001) between the
mRNA expression levels of the
CYP1 family and SRD5A2 were found in patients with
hypospadias but not in those with
phimosis. Moreover, the methylation levels of the four genes were determined by
bisulfite genomic sequencing. Although the SRD5A2 promoter region showed moderate methylation, no methylation was detected in
CYP1A1, CYP1B1, or AR. There was no significant difference in SRD5A2 promoter methylation level between
hypospadias and
phimosis patients. Negative correlations were found between the methylation level of SRD5A2, especially at the - 221 Sp1 site, and the
CYP1 family mRNA expression levels (
CYP1A1, p = 0.002; CYP1B1, p = 0.007) in
hypospadias patients, but not in
phimosis patients. The significant positive association of
mRNA expression level and the negative association of methylation level of the SRD5A2 gene with the
mRNA expression levels of
CYP1 family genes in the preputial tissue seem to indicate the chemical exposure of patients with
hypospadias.