Analysis of Four Polymorphisms Located at the Promoter of the Estrogen Receptor Alpha ESR1 Gene in a Population With Gender Incongruence

[Abstract] Introduction: Gender incongruence defines a state in which individuals feel discrepancy between the sex assigned at birth and their gender. Some of these people make a social transition from male to female (transwomen) or from female to male (trans men). By contrast, the word cisgender describes a person whose gender identity is consistent with their sex assigned at birth. Aim: To analyze the implication of the estrogen receptor a gene (ESR1) in the genetic basis of gender incongruence. Main Outcome Measures: Polymorphisms rs9478245, rs3138774, rs2234693, rs9340799. Method: We carried out the analysis of 4 polymorphisms located at the promoter of the ESR1 gene (C1 ¼ rs9478245, C2 ¼ rs3138774, C3 ¼ rs2234693, and C4 ¼ rs9340799) in a population of 273 trans women, 226 trans men, and 537 cis gender controls. For SNP polymorphisms, the allele and genotype frequencies were analyzed by c2 test. The strength of the SNP associations with gender incongruence was measured by binary logistic regression. For the STR polymorphism, the mean number of repeats were analyzed by the ManneWhitney U test. Measurement of linkage disequilibrium and haplotype frequencies were also performed. Results: The C2 median repeats were shorter in the trans men population. Genotypes S/S and S/L for the C2 polymorphism were overrepresented in the trans men group (P ¼ .012 and P ¼ .003 respectively). We also found overtransmission of the A/A genotype (C4) in the trans men population (P ¼ .017), while the A/G genotype (C4) was subrepresented (P ¼ .009]. The analyzed polymorphisms were in linkage disequilibrium. In the trans men population, the T(C1)-L(C2)-C(C3)-A(C4) haplotype was overrepresented (P ¼ .019) while the T(C1)-L(C2)-C(C3)-G(C4) was subrepresented (P ¼ .005). Conclusion: The ESR1 is associated with gender incongruence in the trans men populationThis work was supported by grants: ED431B 019/02 (EP), PGC2018-094919-B-C21 (AG), PGC2018-094919-B-C22 (RF), and FPU 15/02558 (JCC)Xunta de Galicia; ED431B 019/0

Gender-Affirming Hormone Therapy Modifies the CpG Methylation Pattern of the ESR1 Gene Promoter After Six Months of Treatment in Transmen

[Abstract] Background Brain sexual differentiation is a process that results from the effects of sex steroids on the developing brain. Evidence shows that epigenetics plays a main role in the formation of enduring brain sex differences and that the estrogen receptor α (ESR1) is one of the implicated genes. Aim To analyze whether the methylation of region III (RIII) of the ESR1 promoter is involved in the biological basis of gender dysphoria. Methods We carried out a prospective study of the CpG methylation profile of RIII (−1,188 to −790 bp) of the ESR1 promoter using bisulfite genomic sequencing in a cisgender population (10 men and 10 women) and in a transgender population (10 trans men and 10 trans women), before and after 6 months of gender-affirming hormone treatment. Cisgender and transgender populations were matched by geographical origin, age, and sex. DNAs were treated with bisulfite, amplified, cloned, and sequenced. At least 10 clones per individual from independent polymerase chain reactions were sequenced. The analysis of 671 bisulfite sequences was carried out with the QUMA (QUantification tool for Methylation Analysis) program. Outcomes The main outcome of this study was RIII analysis using bisulfite genomic sequencing. Results We found sex differences in RIII methylation profiles in cisgender and transgender populations. Cismen showed a higher methylation degree than ciswomen at CpG sites 297, 306, 509, and at the total fragment (P ≤ .003, P ≤ .026, P ≤ .001, P ≤ .006). Transmen showed a lower methylation level than trans women at sites 306, 372, and at the total fragment (P ≤ .0001, P ≤ .018, P ≤ .0107). Before the hormone treatment, transmen showed the lowest methylation level with respect to cisgender and transgender populations, whereas transwomen reached an intermediate methylation level between both the cisgender groups. After the hormone treatment, transmen showed a statistically significant methylation increase, whereas transwomen showed a non-significant methylation decrease. After the hormone treatment, the RIII methylation differences between transmen and transwomen disappeared, and both transgender groups reached an intermediate methylation level between both the cisgender groups. Clinical Implications Clinical implications in the hormonal treatment of trans people. Strengths & Limitations Increasing the number of regions analyzed in the ESR1 promoter and increasing the number of tissues analyzed would provide a better understanding of the variation in the methylation pattern. Conclusions Our data showed sex differences in RIII methylation patterns in cisgender and transgender populations before the hormone treatment. Furthermore, before the hormone treatment, transwomen and transmen showed a characteristic methylation profile, different from both the cisgender groups. But the hormonal treatment modified RIII methylation in trans populations, which are now more similar to their gender. Therefore, our results suggest that the methylation of RIII could be involved in gender dysphoria.This work was supported by grants: Xunta de Galicia ED431 B 019/02 (EP), PGC2018-094919-B-C21 (AG), Ministerio de ciencia, innovación y Universidades PGC2018-094919-B-C22 (RF, EP). J. Cortés-Cortés was supported by a doctoral fellowship FPU 15/02558Xunta de Galicia ED431 B 019/0

Analyses of karyotype by G-banding and high-resolution microarrays in a gender dysphoria population

Gender Dysphoria is characterized by a marked incongruence between the cerebral sex and biological sex. To investigate the possible influence of karyotype on the etiology of Gender Dysphoria we carried out the cytogenetic analysis of karyotypes in 444 male-to-females (MtFs) and 273 female-to-males (FtMs) that attended the Gender Identity Units of Barcelona and Málaga (Spain) between 2000 and 2016. The karyotypes from 23 subjects (18 MtFs and 5 FtMs) were also analysed by Affymetrix CytoScan™ high-density (HD) arrays. Our data showed a higher incidence of cytogenetic alterations in Gender Dysphoria (2.65%) than in the general population (0.53%) (p < 0.0001). When G-banding was performed, 11 MtFs (2.48%) and 8 FtMs (2.93%) showed a cytogenetic alteration. Specifically, Klinefelter syndrome frequency was significantly higher (1.13%) (p < 0.0001), however Turner syndrome was not represented in our sample (p < 0.61). At molecular level, HD microarray analysis revealed a 17q21.31 microduplication which encompasses the gene KANSL1 (MIM612452) in 5 out of 18 MtFs and 2 out of 5 FtMs that corresponds to a copy-number variation region in chromosome 17q21.31. In conclusion, we confirm a significantly high frequency of aneuploidy, specifically Klinefelter syndrome and we identified in 7 out of 23 GD individuals the same microduplication of 572 Kb which encompasses the KANSL1 gene