Association of ESR2, AR and CYP19A1 genes in a sample of male Russian patients with congenital irreversible disorders of gender identity

Introduction. The etiology of transsexualism remains unknown to date, since this phenomenon is caused by a complex of reasons. Family studies have confirmed the role of genetic factors in the violation of sexual self-identification. Data on the association between the polymorphism of genes involved in the hormonal regulation system: androgen (AR) and estrogen (ESR2) receptors, as well as aromatase (CYP19A1), and transsexualism in different samples were obtained. In Russia, such studies have not been conducted to date. The purpose of this study is to study the genetic association of the AR, ESR2 and CYP19A1 genes with the diagnosis of transsexualism in a sample of Russian patients. Material and methods. The study was conducted on a sample of male patients with congenital irreversible disorders of gender identity (n=191) with varying degrees of severity of the clinical picture (“core” form, “transitional” and “marginal”) and a control group of men without gender dysphoria (n=129). Results. No statistically significant association was found between transsexualism and polymorphic variants of the three genes, which is consistent with previously published studies. In the group of patients, the frequency of the SS genotypes (containing only alleles with a length shorter than the median value) of the ESR2 gene (57.07%) and the L genotype (with a length longer than the median value) of the AR gene (53.93%) is higher than in the control group (48.46% and 43.41%, respectively). Also, when including only “core” and “transitional” patients in the group, a tendency to increase the observed differences with men without gender dysphoria was revealed (p=0.06). Conclusion. Results of this work indirectly confirm the involvement of the androgen receptor in the development of transsexualism. In the future, it is desirable to expand the range of markers studied for the connection with it, as well as to conduct similar studies on new samples.