Epigenetic Effects of Gender-Affirming Hormone Treatment: A Pilot Study of the ESR2 Promoter’s Methylation in AFAB People

Abstract

Virilization of gender-incongruent subjects to whom were assigned the female gender at birth (AFAB) is achieved through testosterone administration. Inter-individual differences in the timing and acquisition of phenotypic characteristics, even if the same hormone preparations and regimens are used, are frequently observed. Polymorphisms of sex hormone receptors and methylation of their gene promoters, as well of several imprinted genes as H19, may underlie the differential response to treatment. Thus, the aim of this study was to examine the possible relationship between the CpG methylation profile of the estrogen receptor 2 gene (ESR2) and H19 promoters and their influence on phenotype modifications in a cohort of AFAB people at baseline (T0) and after 6 mo (T6) and 12 mo (T12) of testosterone therapy (testosterone enanthate, 250 mg i.m. every 28 d). A total of 13 AFAB subjects (mean age 29.3 ± 12.6) were recruited. The percentage of methylation of the ESR2 promoter significantly increased at T6 (adj. p = 0.001) and T12 (adj. p = 0.05), while no difference was detected for H19 (p = 0.237). Methylation levels were not associated with androgen receptor (AR)/estrogen receptor beta (ERβ) polymorphisms nor hormone levels at baseline and after six months of treatment. On the other hand, total testosterone level and patient age resulted in being significantly associated with ESR2 methylation after twelve months of treatment. Finally, the difference in ESR2 promoter methylation between T6 and baseline was significantly associated with the number of CA repeats of the ERβ receptor, adjusted vs. all considered variables (R2 = 0.62, adj. R2 = 0.35). No associations were found with CAG repeats of the AR, age, and estradiol and testosterone levels. Despite the small sample size, we can hypothesize that treatment with exogenous testosterone can modify the ESR2 methylation pattern. Our data also indicated that epigenetic changes may be regulated, suggesting that the modulation of estrogen signaling is relevant shortly after the beginning of the treatment up to T6, with no further significant modification at T12. Furthermore, estrogen receptor methylation appears to be associated with the age of the subjects and exogenous testosterone administration, representing a marker of androgenic treatment. Nonetheless, it will be necessary to increase the number of subjects to evaluate how epigenetic regulation might play a relevant role in the modulation of phenotypical changes after testosterone treatment.

Erectile function and androgen and estrogen beta receptor gene polymorphisms in acromegalic men

“…Although it did not reach statistical significance, we also found a trend of association between a longer CAG trait in the AR and cardiomyopathy. The length of these polymorphic traits has been investigated in various conditions due to their possible role in modulating receptor activity essentially by modifying the transcriptional activity of the AR and ER-beta receptor [ 10 ]. CAG repeats in the AR gene, in particular, have been extensively studied and a higher number of CAG repeats has been associated with reduced receptor activity [ 24 ].…”

“…A peripheral venous blood sample was collected to extract DNA from leukocytes using the Wizard Genomic DNA Purification Kit (Promega, Madison, WI, USA). After quantification by NanoDrop ND-2000 (Thermo Fisher Scientific, Waltham, MA, USA), the extracted DNA was used to determine the length of the polymorphic fragments in the androgen receptor (AR) and estrogen receptor beta (ERβ) genes (CAG and CA repeats, respectively) by fragment analysis (3500 Genetic Analyzer, Applied Biosystems) as previously described [ 10 ]. Supplementary Table 1 shows the primers used for the CA and CAG analyses.…”

“…The AR and ERβ genes, in fact, contain polymorphic fragments with CAG and CA repeats, respectively. The length of these tracts can influence the regulation of receptor activity [ 10 ], but the extent of their influence in andrological disorders of acromegalic patients has not been investigated. The multicenter study by Lotti et al showed a high incidence of ED in acromegalic subjects (24/57), often in association with other cardio-metabolic comorbidities [ 11 ].…”

Gene Variants and Epigenetics That Lead to Gender Dysphoria

“…It is thought that gender dysphoria is a consequence of atypical cerebral sexual differentiation; however, it is now known that multiple structures and networks are involved instead of a single area [24,27]. This indicates that sex hormones play an important role in sexual differentiation of the brain, which can be concluded that hormonal and genetics deviations might cause a discrepancy between the sexual brain and genital differentiation, and eventually leads to gender dysphoria [22,43].…”