Differential Methylation of 11-Oxyandrogen Biosynthetic Pathway Genes in Girls with High DHEAS Levels

Abstract

Context: Premature adrenarche in girls is defined biochemically by an increase in adrenal androgen (DHEA and DHEAS) levels above the age-specific reference range before age 8 years. Recently, increased levels of 11-oxyandrogens have also been observed in girls with premature adrenarche and it is hypothesized that epigenetic modifications, specifically CpG methylation, may affect gene expression and/or activity of steroidogenic enzymes. Objective: To determine whether circulating DHEAS levels in pre-pubertal girls are associated with methylation status of genes involved in DHEAS and 11-oxyandrogen steroidogenesis. Design and Methods: Ninety-seven healthy girls followed since the age of 3 years were classified, according to DHEAS serum concentration at age 6-7 years, as normal DHEAS (< 42 μg/dL [75th percentile for population]) or high DHEAS (≥ 42 μg/dL). At Tanner stage 2, methylation status of CpG sites located in genes SULT2A1, HSD11B1, HSD11B2, CYP11B1, HSD17B2 and HSD17B5 were analyzed in genomic DNA from peripheral blood leukocytes either by Methylation-Sensitive Restriction Enzymes Quantitative PCR assay or by Melting Curve Analysis Methylation assay. Results: Significantly lower methylation levels were detected in the CYP11B1 gene in girls with high versus normal serum DHEAS, with no differences found in the other genes. In addition, we found a significant inverse correlation between CYP11B1 methylation and insulin level at Tanner 1 and BMI at Tanner 1 and 2 in the whole cohort. Conclusion: These results suggest that a lower methylation of CYP11B1 could be a mechanism contributing to increased concentrations of 11-oxyandrogens in premature adrenarche and to the associated metabolic risk.