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Fernández R, Zubiaurre-Elorza L, Santisteban A, Ojeda N, Collet S, Kiyar M, T'Sjoen G, Mueller SC, Guillamon A, Pásaro E. CBLL1 is hypomethylated and correlates with cortical thickness in transgender men before gender affirming hormone treatment. Sci Rep 2023; 13:21609. [PMID: 38062063 PMCID: PMC10703770 DOI: 10.1038/s41598-023-48782-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Gender identity refers to the consciousness of being a man, a woman or other condition. Although it is generally congruent with the sex assigned at birth, for some people it is not. If the incongruity is distressing, it is defined as gender dysphoria (GD). Here, we measured whole-genome DNA methylation by the Illumina © Infinium Human Methylation 850k array and reported its correlation with cortical thickness (CTh) in 22 transgender men (TM) experiencing GD versus 25 cisgender men (CM) and 28 cisgender women (CW). With respect to the methylation analysis, TM vs. CW showed significant differences in 35 CpGs, while 2155 CpGs were found when TM vs. CM were compared. With respect to correlation analysis, TM showed differences in methylation of CBLL1 and DLG1 genes that correlated with global and left hemisphere CTh. Both genes were hypomethylated in TM compared to the cisgender groups. Early onset TM showed a positive correlation between CBLL1 and several cortical regions in the frontal (left caudal middle frontal), temporal (right inferior temporal, left fusiform) and parietal cortices (left supramarginal and right paracentral). This is the first study relating CBLL1 methylation with CTh in transgender persons and supports a neurodevelopmental hypothesis of gender identity.
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Affiliation(s)
- Rosa Fernández
- Centro Interdisciplinar de Química E Bioloxía - CICA. Departamento de Psicología, Universidade da Coruña, Grupo DICOMOSA, Campus Elviña S/N, 15071, A Coruña, Spain.
- Instituto de Investigación Biomédica de A Coruña (INIBIC), 15071, Oza, A Coruña, Spain.
| | - Leire Zubiaurre-Elorza
- Departamento de Psicología, Facultad de Ciencias de la Salud, Universidad de Deusto, Bilbao, Spain
| | - Andrea Santisteban
- Centro Interdisciplinar de Química E Bioloxía - CICA. Departamento de Psicología, Universidade da Coruña, Grupo DICOMOSA, Campus Elviña S/N, 15071, A Coruña, Spain
| | - Natalia Ojeda
- Departamento de Psicología, Facultad de Ciencias de la Salud, Universidad de Deusto, Bilbao, Spain
| | - Sarah Collet
- Department of Endocrinology, Ghent University Hospital, 9000, Ghent, Belgium
| | - Meltem Kiyar
- Department of Experimental Clinical and Health Psychology, Ghent University, 9000, Ghent, Belgium
| | - Guy T'Sjoen
- Department of Endocrinology, Center for Sexology and Gender, Ghent University Hospital, 9000, Ghent, Belgium
| | - Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, 9000, Ghent, Belgium
| | - Antonio Guillamon
- Departamento de Psicobiología, Facultad de Psicología, Universidad Nacional de Educación a Distancia, 28040, Madrid, Spain.
| | - Eduardo Pásaro
- Centro Interdisciplinar de Química E Bioloxía - CICA. Departamento de Psicología, Universidade da Coruña, Grupo DICOMOSA, Campus Elviña S/N, 15071, A Coruña, Spain
- Instituto de Investigación Biomédica de A Coruña (INIBIC), 15071, Oza, A Coruña, Spain
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Yoshida T, Matsubara K, Ogata-Kawata H, Miyado M, Ishiwata K, Nakabayashi K, Hata K, Kageyama I, Tamaoka S, Shimada Y, Fukami M, Sasaki S. Variations in gender identity and sexual orientation of university students. Sex Med 2023; 11:qfad057. [PMID: 37965377 PMCID: PMC10642543 DOI: 10.1093/sexmed/qfad057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 09/28/2023] [Accepted: 10/05/2023] [Indexed: 11/16/2023] Open
Abstract
Background Previous studies have shown that a small percentage of people in the general population have atypical gender identity and/or sexual orientation. Aim This study aimed to explore variations in gender identity and sexual orientation in university students and determine genetic factors associated with these variations. Methods Deviations from complete gender congruence and exclusive heterosexual orientation in 736 Japanese university students were quantitatively assessed with self-assessment questionnaires. Next, we conducted genetic tests for 80 participants who showed relatively low gender identity scores and/or atypical sexual orientation. These genetic tests consisted of repeat number analysis of the androgen receptor gene (AR) and a SKAT-O: an optimal unified sequence kernel association test, which is an exome-based rare variant association study. The results of the genetic tests were compared with the Japanese reference data and the results of our 637 control samples. Outcomes We calculated the gender identity and sexual orientation scores of all participants and analyzed the molecular data of 80 selected participants. Results The gender identity scores of 736 participants were broadly distributed: only ~15% of natal males and ~5% of natal females had the maximum score that corresponds to complete gender congruence. The sexual orientation scores also varied: ~80% of natal males and ~60% of natal females showed exclusive heterosexual orientation. We found no association between gender characteristics and AR repeat numbers. The SKAT-O showed that rare damaging variants of TDRP and 3 other genes were more common in the 80 participants than in the control group. Clinical Implications Our data support the view that gender is a phenotypic continuum rather than a binary trait. Strength and Limitations This study quantitatively assessed the gender characteristics of a large cohort of university students. Moreover, we conducted systematic screening for genetic factors associated with gender variations. The weaknesses of the study were the limited analytic power of the questionnaires, the relatively small sample for molecular analyses, and incomplete clinical information and relatively advanced ages of the control group. Conclusion This study revealed significant variations in gender identity and sexual orientation in university students, which may be partly associated with variants in TDRP or other genes.
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Affiliation(s)
- Tomoko Yoshida
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Keiko Matsubara
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Hiroko Ogata-Kawata
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Mami Miyado
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Keisuke Ishiwata
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Kazuhiko Nakabayashi
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Kenichiro Hata
- Department of Maternal-Fetal Biology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Ikuko Kageyama
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Satoshi Tamaoka
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Yukiko Shimada
- Department of Child Studies, Faculty of Human Development, Kokugakuin University, Kanagawa, 225-0003, Japan
| | - Maki Fukami
- Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, 157-8535, Japan
| | - Shoko Sasaki
- Graduate School of Arts and Letters, Meiji University, Tokyo ,101-0064, Japan
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Levin RN, Erickson-Schroth L, Mak K, Edmiston EK. Biological studies of transgender identity: A critical review. JOURNAL OF GAY & LESBIAN MENTAL HEALTH 2022. [DOI: 10.1080/19359705.2022.2127042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Rachel N. Levin
- Departments of Biology and Neuroscience, Pomona College, Claremont, CA, USA
| | | | - Kristie Mak
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - E. Kale Edmiston
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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4
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Liang B, Cheung AS, Nolan BJ. Clinical features and prevalence of Klinefelter syndrome in transgender individuals: A systematic review. Clin Endocrinol (Oxf) 2022; 97:3-12. [PMID: 35394664 PMCID: PMC9540025 DOI: 10.1111/cen.14734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 03/23/2022] [Accepted: 04/03/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Previous studies have suggested a higher prevalence of Klinefelter syndrome amongst transgender individuals. We undertook a systematic review to determine the prevalence of Klinefelter syndrome amongst transgender individuals presumed male at birth and summarize the clinical features and potential treatment implications for individuals with Klinefelter syndrome commencing gender-affirming hormone therapy. DESIGN Using preferred reporting items for systematic review and meta-analysis guidelines, we searched EMBASE, MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL) up to 31 December 2021. All studies reporting on the prevalence or clinical features of transgender individuals with Klinefelter syndrome were included. This study is registered with the International Prospective Register of Systematic Reviews, number CRD42021227916. RESULTS Our search strategy retrieved 11 cohort studies comprising 1376 transgender individuals. In all, 14 of 1376 (1.02%) individuals were diagnosed with Klinefelter syndrome. Based on the seven studies in which karyotype was undertaken in all individuals, the prevalence is 9/1013 (0.88%; 95% CI, 0.41%-1.68%). Case reports highlight unique treatment considerations in this population, including azoospermia, venous thromboembolism, and monitoring of breast cancer and bone health. CONCLUSIONS Compared to the general population, observational studies document a higher prevalence of Klinefelter syndrome amongst transgender individuals, though underdiagnosis in the general population limits conclusions. Routine karyotype in transgender people initiating gender-affirming hormone therapy is not supported unless clinical features of Klinefelter syndrome, such as small testicular volume, or hypergonadotropic hypogonadism are present. Transgender individuals with Klinefelter syndrome need to manage a unique risk profile if they desire feminizing gender-affirming hormone therapy.
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Affiliation(s)
- Bonnie Liang
- Department of Medicine (Austin Health)University of MelbourneHeidelbergVictoriaAustralia
| | - Ada S. Cheung
- Department of Medicine (Austin Health)University of MelbourneHeidelbergVictoriaAustralia
- Department of EndocrinologyAustin HealthHeidelbergVictoriaAustralia
| | - Brendan J. Nolan
- Department of Medicine (Austin Health)University of MelbourneHeidelbergVictoriaAustralia
- Department of EndocrinologyAustin HealthHeidelbergVictoriaAustralia
- Equinox Gender Diverse Health CentreThorne Harbour HealthAbbotsfordVictoriaAustralia
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Gupta R. Gender Affirmation in India—The Current State of Knowledge, Management, Legal and Legislative Situation. Indian J Plast Surg 2022; 55:139-143. [PMID: 36017406 PMCID: PMC9398521 DOI: 10.1055/s-0041-1740528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A mismatch between the birth sex of a person and psychological recognition of self (gender) leads to a gender expression, which is at variance with the societal norms, and thus gives rise to gender incongruence (GI). In the past few years, there has been a significant change in demographics, understanding of etiology, management, laws and legislations in the field of GI. The authors, who have been performing gender affirmative surgeries (GAS) since the past 27 years, present their experience in gender affirmation together with the current state of knowledge. Recent studies report a significant rise in prevalence of GI, which is similar to the experience of author and other large volume Gender identity clinics in India and worldwide. This article endeavors to provide the medical professional with the current state of knowledge in the field of GI, so that they are better equipped to optimally manage these patients.
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Affiliation(s)
- Richie Gupta
- Department of Plastic, Aesthetic and Reconstructive Surgery, and Gender Identity Clinic, Fortis Hospital, Delhi, India
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6
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Should chromosomal analysis be performed routinely during the baseline evaluation of the gender affirmation process? The outcomes of a large cohort of gender dysphoric individuals. Int J Impot Res 2022:10.1038/s41443-022-00582-4. [PMID: 35581420 DOI: 10.1038/s41443-022-00582-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 04/28/2022] [Accepted: 05/03/2022] [Indexed: 11/08/2022]
Abstract
The role of genetics in the etiology of gender dysphoria (GD) is an important yet understudied area. Yet whether genetic analysis should be carried out during the gender affirmation process at all is a matter of debate. This study aims to evaluate the cytogenetic and molecular genetic findings of individuals with GD. We retrospectively reviewed the medical records of individuals with GD who were followed up in a tertiary clinic. After the exclusion criteria were applied, the study sample consisted of 918 individuals with GD; 691 of whom had female-to-male (FtM) and 227 male-to-female (MtF) GD. The cytogenetic analysis revealed that 223 out of 227 (98.2%) individuals with MtF GD had the 46,XY karyotype, while 683 out of 691 (98.8%) individuals with FtM GD had the 46,XX karyotype. In the Y chromosome microdeletion analysis, azospermic factor c (AZFc) deletion was detected in only two individuals with MtF GD. Our findings suggest that there are few chromosomal abnormalities in individuals with GD. Thus, this research calls into question both the role of chromosomal abnormalities in GD etiology and why the application of chromosomal analysis is in Turkey a routine part of the baseline evaluation of GD.
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7
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Brain Sex in Transgender Women Is Shifted towards Gender Identity. J Clin Med 2022; 11:jcm11061582. [PMID: 35329908 PMCID: PMC8955456 DOI: 10.3390/jcm11061582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 01/09/2023] Open
Abstract
Transgender people report discomfort with their birth sex and a strong identification with the opposite sex. The current study was designed to shed further light on the question of whether the brains of transgender people resemble their birth sex or their gender identity. For this purpose, we analyzed a sample of 24 cisgender men, 24 cisgender women, and 24 transgender women before gender-affirming hormone therapy. We employed a recently developed multivariate classifier that yields a continuous probabilistic (rather than a binary) estimate for brains to be male or female. The brains of transgender women ranged between cisgender men and cisgender women (albeit still closer to cisgender men), and the differences to both cisgender men and to cisgender women were significant (p = 0.016 and p < 0.001, respectively). These findings add support to the notion that the underlying brain anatomy in transgender people is shifted away from their biological sex towards their gender identity.
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8
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Gall-Duncan T, Sato N, Yuen RKC, Pearson CE. Advancing genomic technologies and clinical awareness accelerates discovery of disease-associated tandem repeat sequences. Genome Res 2022; 32:1-27. [PMID: 34965938 PMCID: PMC8744678 DOI: 10.1101/gr.269530.120] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 11/29/2021] [Indexed: 11/25/2022]
Abstract
Expansions of gene-specific DNA tandem repeats (TRs), first described in 1991 as a disease-causing mutation in humans, are now known to cause >60 phenotypes, not just disease, and not only in humans. TRs are a common form of genetic variation with biological consequences, observed, so far, in humans, dogs, plants, oysters, and yeast. Repeat diseases show atypical clinical features, genetic anticipation, and multiple and partially penetrant phenotypes among family members. Discovery of disease-causing repeat expansion loci accelerated through technological advances in DNA sequencing and computational analyses. Between 2019 and 2021, 17 new disease-causing TR expansions were reported, totaling 63 TR loci (>69 diseases), with a likelihood of more discoveries, and in more organisms. Recent and historical lessons reveal that properly assessed clinical presentations, coupled with genetic and biological awareness, can guide discovery of disease-causing unstable TRs. We highlight critical but underrecognized aspects of TR mutations. Repeat motifs may not be present in current reference genomes but will be in forthcoming gapless long-read references. Repeat motif size can be a single nucleotide to kilobases/unit. At a given locus, repeat motif sequence purity can vary with consequence. Pathogenic repeats can be "insertions" within nonpathogenic TRs. Expansions, contractions, and somatic length variations of TRs can have clinical/biological consequences. TR instabilities occur in humans and other organisms. TRs can be epigenetically modified and/or chromosomal fragile sites. We discuss the expanding field of disease-associated TR instabilities, highlighting prospects, clinical and genetic clues, tools, and challenges for further discoveries of disease-causing TR instabilities and understanding their biological and pathological impacts-a vista that is about to expand.
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Affiliation(s)
- Terence Gall-Duncan
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nozomu Sato
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
| | - Ryan K C Yuen
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Christopher E Pearson
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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9
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Zubiaurre-Elorza L, Cerdán S, Uribe C, Pérez-Laso C, Marcos A, Rodríguez del Cerro MC, Fernandez R, Pásaro E, Guillamon A. The Effects of Testosterone on the Brain of Transgender Men. ANDROGENS: CLINICAL RESEARCH AND THERAPEUTICS 2021; 2:252-260. [PMID: 35024694 PMCID: PMC8744429 DOI: 10.1089/andro.2021.0008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/28/2023]
Abstract
Transgender men (TM) experience an incongruence between the female sex assigned when they were born and their self-perceived male identity. Some TM seek for a gender affirming hormone treatment (GAHT) to induce a somatic transition from female to male through continuous administration of testosterone. GAHT seems to be relatively safe. However, testosterone produces structural changes in the brain as detected by quantitative magnetic resonance imaging. Mainly, it induces an increase in cortical volume and thickness and subcortical structural volume probably due to the anabolic effects. Animal models, specifically developed to test the anabolic hypothesis, suggest that testosterone and estradiol, its aromatized metabolite, participate in the control of astrocyte water trafficking, thereby controlling brain volume.
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Affiliation(s)
- Leire Zubiaurre-Elorza
- Department of Methods and Experimental Psychology, Faculty of Psychology and Education, University of Deusto, Bilbao, Spain
| | - Sebastian Cerdán
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Carme Uribe
- Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Carmen Pérez-Laso
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Alberto Marcos
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | | | - Rosa Fernandez
- Departamento de Psicología, Facultade de Ciencias da Educación, Universidade da Coruña, A Coruña, Spain
| | - Eduardo Pásaro
- Departamento de Psicología, Facultade de Ciencias da Educación, Universidade da Coruña, A Coruña, Spain
| | - Antonio Guillamon
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
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10
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Rosenthal SM. Challenges in the care of transgender and gender-diverse youth: an endocrinologist's view. Nat Rev Endocrinol 2021; 17:581-591. [PMID: 34376826 DOI: 10.1038/s41574-021-00535-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/28/2021] [Indexed: 02/07/2023]
Abstract
An increasing number of transgender and gender-diverse (TGD) youth (early pubertal through to late adolescent, typically 9-10 through to 18 years of age) are seeking medical services to bring their physical sex characteristics into alignment with their gender identity - their inner sense of self as male or female or somewhere on the gender spectrum. Compelling research has demonstrated the clear mental health - even life-saving - benefits of gender-affirming care, but current clinical practice guidelines and standards of care are based on only several short-term and a few medium-term outcomes studies complemented by expert opinion. Nevertheless, although the relative paucity of outcomes data raises concerns, the stance of not intervening until more is known is not a neutral option, and large observational studies evaluating current models of care are necessary and are now underway. This Review highlights key advances in our understanding of transgender and gender-diverse youth, the challenges of providing gender-affirming care, gaps in knowledge and priorities for research.
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Affiliation(s)
- Stephen M Rosenthal
- Department of Pediatrics, Division of Pediatric Endocrinology, Benioff Children's Hospital, University of California San Francisco, San Francisco, CA, USA.
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11
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Ramirez K, Fernández R, Collet S, Kiyar M, Delgado-Zayas E, Gómez-Gil E, Van Den Eynde T, T'Sjoen G, Guillamon A, Mueller SC, Pásaro E. Epigenetics Is Implicated in the Basis of Gender Incongruence: An Epigenome-Wide Association Analysis. Front Neurosci 2021; 15:701017. [PMID: 34489625 PMCID: PMC8418298 DOI: 10.3389/fnins.2021.701017] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction The main objective was to carry out a global DNA methylation analysis in a population with gender incongruence before gender-affirming hormone treatment (GAHT), in comparison to a cisgender population. Methods A global CpG (cytosine-phosphate-guanine) methylation analysis was performed on blood from 16 transgender people before GAHT vs. 16 cisgender people using the Illumina© Infinium Human Methylation 850k BeadChip, after bisulfite conversion. Changes in the DNA methylome in cisgender vs. transgender populations were analyzed with the Partek® Genomics Suite program by a 2-way ANOVA test comparing populations by group and their sex assigned at birth. Results The principal components analysis (PCA) showed that both populations (cis and trans) differ in the degree of global CpG methylation prior to GAHT. The 2-way ANOVA test showed 71,515 CpGs that passed the criterion FDR p < 0.05. Subsequently, in male assigned at birth population we found 87 CpGs that passed both criteria (FDR p < 0.05; fold change ≥ ± 2) of which 22 were located in islands. The most significant CpGs were related to genes: WDR45B, SLC6A20, NHLH1, PLEKHA5, UBALD1, SLC37A1, ARL6IP1, GRASP, and NCOA6. Regarding the female assigned at birth populations, we found 2 CpGs that passed both criteria (FDR p < 0.05; fold change ≥ ± 2), but none were located in islands. One of these CpGs, related to the MPPED2 gene, is shared by both, trans men and trans women. The enrichment analysis showed that these genes are involved in functions such as negative regulation of gene expression (GO:0010629), central nervous system development (GO:0007417), brain development (GO:0007420), ribonucleotide binding (GO:0032553), and RNA binding (GO:0003723), among others. Strengths and Limitations It is the first time that a global CpG methylation analysis has been carried out in a population with gender incongruence before GAHT. A prospective study before/during GAHT would provide a better understanding of the influence of epigenetics in this process. Conclusion The main finding of this study is that the cis and trans populations have different global CpG methylation profiles prior to GAHT. Therefore, our results suggest that epigenetics may be involved in the etiology of gender incongruence.
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Affiliation(s)
- Karla Ramirez
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain.,Laboratory of Neurophysiology, Center for Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Rosa Fernández
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain
| | - Sarah Collet
- Department of Endocrinology, Ghent University, Ghent, Belgium
| | - Meltem Kiyar
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | - Enrique Delgado-Zayas
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain
| | | | | | - Guy T'Sjoen
- Department of Endocrinology, Ghent University, Ghent, Belgium
| | - Antonio Guillamon
- Department of Psychobiology, Faculty of Psychology, National University of Distance Education (UNED), Madrid, Spain
| | - Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
| | - Eduardo Pásaro
- Laboratory of Psychobiology, Department of Psychology, Institute Advanced Scientific Research Center (CICA), University of A Coruña, A Coruña, Spain
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12
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Ramírez KDV, Fernández R, Delgado-Zayas E, Gómez-Gil E, Esteva I, Guillamon A, Pásaro E. Implications of the Estrogen Receptor Coactivators SRC1 and SRC2 in the Biological Basis of Gender Incongruence. Sex Med 2021; 9:100368. [PMID: 34049263 PMCID: PMC8240342 DOI: 10.1016/j.esxm.2021.100368] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/19/2021] [Accepted: 03/30/2021] [Indexed: 12/19/2022] Open
Abstract
Introduction Brain sexual differentiation results from the effects of sex steroids on the developing brain. The presumptive route for brain masculinization is the direct induction of gene expression via activation of the estrogen receptors α and β and the androgen receptor through their binding to ligands and to coactivators, regulating the transcription of multiple genes in a cascade effect. Aim To analyze the implication of the estrogen receptor coactivators SRC-1, SRC-2, and SRC-3 in the genetic basis of gender incongruence. Main Outcome Measures Analysis of 157 polymorphisms located at the estrogen receptor coactivators SRC-1, SRC-2, and SRC-3, in 94 transgender versus 94 cisgender individuals. Method Using SNPStats software, the allele and genotype frequencies were analyzed by χ2, the strength of the association was measured by binary logistic regression, estimating the odds ratio for each genotype. Measurements of linkage disequilibrium and haplotype frequencies were also performed. Results We found significant differences at level P < .05 in 8 polymorphisms that correspond to 5.09% of the total. Three were located in SRC-1 and 5 in SRC-2. The odds ratio analysis showed significant differences at level P < .05 for multiple patterns of inheritance. The polymorphisms analyzed were in linkage disequilibrium. The SRC-1 haplotypes CGA and CGG (global haplotype association P < .009) and the SRC-2 haplotypes GGTAA and GGTAG (global haplotype association P < .005) were overrepresented in the transgender population. Conclusion The coactivators SRC-1 and SRC-2 could be considered as candidates for increasing the list of potential genes for gender incongruence. Ramírez KDV, Fernández R, Delgado-Zayas E, et al. Implications of the Estrogen Receptor Coactivators SRC1 and SRC2 in the Biological Basis of Gender Incongruence. Sex Med 2021;9:100368.
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Affiliation(s)
- Karla Del Valle Ramírez
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain
| | - Rosa Fernández
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain.
| | - Enrique Delgado-Zayas
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain
| | - Esther Gómez-Gil
- Unidad de Identidad de Género, Instituto de Neurociencias, Hospital Clínic, Barcelona, Spain
| | - Isabel Esteva
- Servicio de Endocrinología y Nutrición, Unidad de Identidad de Género del Hospital Regional Universitario de Málaga, Spain
| | - Antonio Guillamon
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Eduardo Pásaro
- Centro de Investigaciones Científicas Avanzadas (CICA), Departamento de Psicología. Universidade da Coruña (UDC), Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), Coruña, Spain
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Mueller SC, Guillamon A, Zubiaurre-Elorza L, Junque C, Gomez-Gil E, Uribe C, Khorashad BS, Khazai B, Talaei A, Habel U, Votinov M, Derntl B, Lanzenberger R, Seiger R, Kranz GS, Kreukels BPC, Kettenis PTC, Burke SM, Lambalk NB, Veltman DJ, Kennis M, Sánchez FJ, Vilain E, Fisher AD, Mascalchi M, Gavazzi G, Orsolini S, Ristori J, Dannlowski U, Grotegerd D, Konrad C, Schneider MA, T'Sjoen G, Luders E. The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group. J Sex Med 2021; 18:1122-1129. [PMID: 37057468 DOI: 10.1016/j.jsxm.2021.03.079] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/22/2021] [Accepted: 03/24/2021] [Indexed: 12/23/2022]
Abstract
BACKGROUND In contrast to cisgender persons, transgender persons identify with a different gender than the one assigned at birth. Although research on the underlying neurobiology of transgender persons has been accumulating over the years, neuroimaging studies in this relatively rare population are often based on very small samples resulting in discrepant findings. AIM To examine the neurobiology of transgender persons in a large sample. METHODS Using a mega-analytic approach, structural MRI data of 803 non-hormonally treated transgender men (TM, n = 214, female assigned at birth with male gender identity), transgender women (TW, n = 172, male assigned at birth with female gender identity), cisgender men (CM, n = 221, male assigned at birth with male gender identity) and cisgender women (CW, n = 196, female assigned at birth with female gender identity) were analyzed. OUTCOMES Structural brain measures, including grey matter volume, cortical surface area, and cortical thickness. RESULTS Transgender persons differed significantly from cisgender persons with respect to (sub)cortical brain volumes and surface area, but not cortical thickness. Contrasting the 4 groups (TM, TW, CM, and CW), we observed a variety of patterns that not only depended on the direction of gender identity (towards male or towards female) but also on the brain measure as well as the brain region examined. CLINICAL TRANSLATION The outcomes of this large-scale study may provide a normative framework that may become useful in clinical studies. STRENGTHS AND LIMITATIONS While this is the largest study of MRI data in transgender persons to date, the analyses conducted were governed (and restricted) by the type of data collected across all participating sites. CONCLUSION Rather than being merely shifted towards either end of the male-female spectrum, transgender persons seem to present with their own unique brain phenotype. Mueller SC, Guillamon A, Zubiaurre-Elorza L, et al. The Neuroanatomy of Transgender Identity: Mega-Analytic Findings From the ENIGMA Transgender Persons Working Group. J Sex Med 2021;18:1122-1129.
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Affiliation(s)
- Sven C Mueller
- Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium
- Department of Personality, Psychological Assessment and Treatment, University of Deusto, Bilbao, Spain
| | - Antonio Guillamon
- Deparment of Psychobiology, National Distance Education University, Madrid, Spain
| | - Leire Zubiaurre-Elorza
- Department of Methods and Experimental Psychology, Faculty of Psychology and Education, University of Deusto, Bilbao, Spain
| | - Carme Junque
- Faculty of Medicine, University of Barcelona, Barcelona, Spain
| | | | - Carme Uribe
- Faculty of Medicine, University of Barcelona, Barcelona, Spain
| | - Behzad S Khorashad
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
- Department of Women's and Children's Health, Karolinska University Hospital, Karolinska Institute, Solna, Stockholm, Sweden
| | - Behnaz Khazai
- Keck School of Medicine, Mark and Mary Stevens Neuroimaging and Informatics Institute, Los Angeles, CA, USA
| | - Ali Talaei
- Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ute Habel
- Psychiatry, Psychotherapy, and Psychosomatics, University Clinic RWTH, Aachen, Germany
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-10), Jülich, Germany
| | - Mikhail Votinov
- Psychiatry, Psychotherapy, and Psychosomatics, University Clinic RWTH, Aachen, Germany
- Research Centre Jülich, Institute of Neuroscience and Medicine (INM-10), Jülich, Germany
| | - Birgit Derntl
- Deptarment of Psychiatry and Psychotherapy, University of Tuebingen, Germany
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rene Seiger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Georg S Kranz
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hongkong
| | | | | | - Sarah M Burke
- Psychology, Developmental and Educational Psychology, University of Leiden, Leiden, The Netherlands
| | - Nils B Lambalk
- Obstetrics and Gynaecology, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Dick J Veltman
- Psychiatry, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Mathilde Kennis
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, The Netherlands
| | | | - Eric Vilain
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, USA
- Department of Genomics and Precision Medicine, George Washington University, Washington, DC, USA
| | - Alessandra Daphne Fisher
- Andrology, Women's Endocrinology, Gender Incongruence Unit, Careggi University Hospital, Florence, Italy
| | - Mario Mascalchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy
| | - Gioele Gavazzi
- Department of Neuroscience, Psychology, Drug Research, Child Health, University of Florence, Florence, Italy
| | - Stefano Orsolini
- Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy
| | - Jiska Ristori
- Center for Genetic Medicine Research, Children's National Hospital, Washington, DC, USA
| | - Udo Dannlowski
- Institute for Translational Psychiatry, University of Muenster, Muenster, Germany
| | - Dominik Grotegerd
- Institute for Translational Psychiatry, University of Muenster, Muenster, Germany
| | - Carsten Konrad
- Department of Psychiatry and Psychotherapy, Agaplesion Diakonieklinikum, Rotenburg, Germany
| | | | - Guy T'Sjoen
- Department of Endocrinology & Center for Sexology and Gender, Ghent University Hospital, Ghent, Belgium
| | - Eileen Luders
- School of Psychology, University of Auckland, Auckland, New Zealand
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Swaab DF, Wolff SEC, Bao AM. Sexual differentiation of the human hypothalamus: Relationship to gender identity and sexual orientation. HANDBOOK OF CLINICAL NEUROLOGY 2021; 181:427-443. [PMID: 34238476 DOI: 10.1016/b978-0-12-820683-6.00031-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gender identity (an individual's perception of being male or female) and sexual orientation (heterosexuality, homosexuality, or bisexuality) are programmed into our brain during early development. During the intrauterine period in the second half of pregnancy, a testosterone surge masculinizes the fetal male brain. If such a testosterone surge does not occur, this will result in a feminine brain. As sexual differentiation of the brain takes place at a much later stage in development than sexual differentiation of the genitals, these two processes can be influenced independently of each other and can result in gender dysphoria. Nature produces a great variability for all aspects of sexual differentiation of the brain. Mechanisms involved in sexual differentiation of the brain include hormones, genetics, epigenetics, endocrine disruptors, immune response, and self-organization. Furthermore, structural and functional differences in the hypothalamus relating to gender dysphoria and sexual orientation are described in this review. All the genetic, postmortem, and in vivo scanning observations support the neurobiological theory about the origin of gender dysphoria, i.e., it is the sizes of brain structures, the neuron numbers, the molecular composition, functions, and connectivity of brain structures that determine our gender identity or sexual orientation. There is no evidence that one's postnatal social environment plays a crucial role in the development of gender identity or sexual orientation.
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Affiliation(s)
- Dick F Swaab
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Samantha E C Wolff
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, An Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Ai-Min Bao
- Department of Neurobiology and Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; NHC and CAMS Key Laboratory of Medical Neurobiology, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.
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Skordis N, Kyriakou A, Dror S, Mushailov A, Nicolaides NC. Gender dysphoria in children and adolescents: an overview. Hormones (Athens) 2020; 19:267-276. [PMID: 32020566 DOI: 10.1007/s42000-020-00174-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/22/2020] [Indexed: 02/07/2023]
Abstract
Over the last decade, we have witnessed considerable progress in gender dysphoria (GD) terminology in an attempt to better describe the condition based on certain criteria. The ever-increasing social acceptance and destigmatization of children and adolescents with GD have resulted in an increased number of transgender individuals seeking endocrine care. In addition to terminology and diagnostic criteria, the tremendous progress of genetics and neuroimaging has enabled us to have a deeper understanding of the complex pathogenesis of GD. Although helpful guidelines for treatment with GnRH analogs and gender-affirming hormones have been proposed, several challenges and controversies still exist. In this article, the current knowledge about GD in adolescents is reviewed, with particular emphasis on terminology, clinical manifestations, and epidemiologic data. The neurobiological basis of the condition is presented, and both hormonal treatment and mental issues of transgender individuals are discussed. Undoubtedly, further research will optimize the diagnostic and therapeutic approach of children and adolescents with GD.
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Affiliation(s)
- Nicos Skordis
- Division of Pediatric Endocrinology, Paedi Center for Specialized Pediatrics, Nicosia, Cyprus.
- St George's, University London Medical Program at the University of Nicosia Medical School, Nicosia, Cyprus.
| | - Andreas Kyriakou
- Developmental Endocrinology Research Group, School of Medicine, University of Glasgow, Glasgow, UK
| | - Shai Dror
- St George's, University London Medical Program at the University of Nicosia Medical School, Nicosia, Cyprus
| | - Avital Mushailov
- St George's, University London Medical Program at the University of Nicosia Medical School, Nicosia, Cyprus
| | - Nicolas C Nicolaides
- Division of Endocrinology, Metabolism and Diabetes, First Department of Pediatrics, National and Kapodistrian University of Athens Medical School, "Aghia Sophia" Children's Hospital, Athens, Greece
- Division of Endocrinology and Metabolism, Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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Fernández R, Ramírez K, Gómez-Gil E, Cortés-Cortés J, Mora M, Aranda G, Zayas ED, Esteva I, Almaraz MC, Guillamon A, Pásaro E. Gender-Affirming Hormone Therapy Modifies the CpG Methylation Pattern of the ESR1 Gene Promoter After Six Months of Treatment in Transmen. J Sex Med 2020; 17:1795-1806. [PMID: 32636163 DOI: 10.1016/j.jsxm.2020.05.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/25/2020] [Accepted: 05/27/2020] [Indexed: 01/15/2023]
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. Fernández R, Ramírez K, Gómez-Gil E, et al. Gender-Affirming Hormone Therapy Modifies the CpG Methylation Pattern of the ESR1 Gene Promoter After Six Months of Treatment in Transmen. J Sex Med 2020;17:1795-1806.
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Affiliation(s)
- Rosa Fernández
- Departamento de Psicología, Centro de Investigaciones Científicas Avanzadas (CICA), Universidade da Coruña (UDC), Campus de Elviña, A Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), CHUAC, SERGAS, A Coruña, Spain.
| | - Karla Ramírez
- Departamento de Psicología, Centro de Investigaciones Científicas Avanzadas (CICA), Universidade da Coruña (UDC), Campus de Elviña, A Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), CHUAC, SERGAS, A Coruña, Spain
| | - Esther Gómez-Gil
- Unidad de Identidad de Género, Instituto de Neurociencias, Hospital Clínic, I.D.I.B.A.P.S., Barcelona, Spain
| | - Joselyn Cortés-Cortés
- Departamento de Psicología, Centro de Investigaciones Científicas Avanzadas (CICA), Universidade da Coruña (UDC), Campus de Elviña, A Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), CHUAC, SERGAS, A Coruña, Spain
| | - Mireia Mora
- Departmento de Endocrinología y Nutrición, Hospital Clínic, Barcelona, Spain
| | - Gloria Aranda
- Departmento de Endocrinología y Nutrición, Hospital Clínic, Barcelona, Spain
| | - Enrique Delgado Zayas
- Departamento de Psicología, Centro de Investigaciones Científicas Avanzadas (CICA), Universidade da Coruña (UDC), Campus de Elviña, A Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), CHUAC, SERGAS, A Coruña, Spain
| | - Isabel Esteva
- Servicio de Endocrinología y Nutrición, Unidad de Identidad de Género del Hospital Regional Universitario de Málaga, Málaga, Spain
| | - Mari Cruz Almaraz
- Servicio de Endocrinología y Nutrición, Unidad de Identidad de Género del Hospital Regional Universitario de Málaga, Málaga, Spain
| | - Antonio Guillamon
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain
| | - Eduardo Pásaro
- Departamento de Psicología, Centro de Investigaciones Científicas Avanzadas (CICA), Universidade da Coruña (UDC), Campus de Elviña, A Coruña, Spain; Instituto de Investigación Biomédica de A Coruña (INIBIC), CHUAC, SERGAS, A Coruña, Spain
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Gómez Jiménez FR, Semenyna SW, Vasey PL. The relationship between fraternal birth order and childhood sex‐atypical behavior among the Istmo Zapotec
muxes. Dev Psychobiol 2020; 62:792-803. [DOI: 10.1002/dev.21987] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 12/22/2022]
Affiliation(s)
| | - Scott W. Semenyna
- Department of Psychology University of Lethbridge Lethbridge Alberta Canada
| | - Paul L. Vasey
- Department of Psychology University of Lethbridge Lethbridge Alberta Canada
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Analysis of Four Polymorphisms Located at the Promoter of the Estrogen Receptor Alpha ESR1 Gene in a Population With Gender Incongruence. Sex Med 2020; 8:490-500. [PMID: 32409288 PMCID: PMC7471065 DOI: 10.1016/j.esxm.2020.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/28/2020] [Accepted: 04/05/2020] [Indexed: 02/06/2023] Open
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 (trans women) 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 α 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 = rs9478245, C2 = rs3138774, C3 = rs2234693, and C4 = 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 χ2 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 Mann-Whitney 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 = .012 and P = .003 respectively). We also found overtransmission of the A/A genotype (C4) in the trans men population (P = .017), while the A/G genotype (C4) was subrepresented (P = .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 = .019) while the T(C1)-L(C2)-C(C3)-G(C4) was subrepresented (P = .005). CONCLUSION The ESR1 is associated with gender incongruence in the trans men population. Fernández R, Delgado-Zayas E,RamírezK, et al. Analysis of Four Polymorphisms Located at the Promoter of the Estrogen Receptor Alpha ESR1 Gene in a Population With Gender Incongruence. Sex Med 2020;8:490-500.
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Ristori J, Cocchetti C, Romani A, Mazzoli F, Vignozzi L, Maggi M, Fisher AD. Brain Sex Differences Related to Gender Identity Development: Genes or Hormones? Int J Mol Sci 2020; 21:ijms21062123. [PMID: 32204531 PMCID: PMC7139786 DOI: 10.3390/ijms21062123] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/21/2020] [Accepted: 02/28/2020] [Indexed: 12/19/2022] Open
Abstract
The complex process of sexual differentiation is known to be influenced by biological and environmental determinants. The present review has the aim of summarizing the most relevant studies on the biological basis of sexual development, and in particular, it focuses on the impact of sex hormones and genetic background on the development of sexual differentiation and gender identity. The authors conducted a search of published studies on Medline (from January 1948 to December 2019). The evidence suggests that the sexual dimorphic brain could be the anatomical substrate of psychosexual development, on which gonadal hormones may have a shaping role during prenatal and pubertal periods. Additionally, according to several heritability studies, genetic components may have a role, but a promising candidate gene has not been identified. Even though growing evidence underlines the primary role of biological factors on psychosexual development, further studies are necessary to better explain their complex interactions.
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Affiliation(s)
- Jiska Ristori
- Andrology, Women’s Endocrinology and Gender Incongruence, Careggi University Hospital, Viale Pieraccini 6, 50139 Florence, Italy; (J.R.); (C.C.); (A.R.); (F.M.); (L.V.)
| | - Carlotta Cocchetti
- Andrology, Women’s Endocrinology and Gender Incongruence, Careggi University Hospital, Viale Pieraccini 6, 50139 Florence, Italy; (J.R.); (C.C.); (A.R.); (F.M.); (L.V.)
| | - Alessia Romani
- Andrology, Women’s Endocrinology and Gender Incongruence, Careggi University Hospital, Viale Pieraccini 6, 50139 Florence, Italy; (J.R.); (C.C.); (A.R.); (F.M.); (L.V.)
| | - Francesca Mazzoli
- Andrology, Women’s Endocrinology and Gender Incongruence, Careggi University Hospital, Viale Pieraccini 6, 50139 Florence, Italy; (J.R.); (C.C.); (A.R.); (F.M.); (L.V.)
| | - Linda Vignozzi
- Andrology, Women’s Endocrinology and Gender Incongruence, Careggi University Hospital, Viale Pieraccini 6, 50139 Florence, Italy; (J.R.); (C.C.); (A.R.); (F.M.); (L.V.)
| | - Mario Maggi
- Endocrinology, Careggi University Hospital, Viale Pieraccini 6, 50139 Florence, Italy;
| | - Alessandra Daphne Fisher
- Andrology, Women’s Endocrinology and Gender Incongruence, Careggi University Hospital, Viale Pieraccini 6, 50139 Florence, Italy; (J.R.); (C.C.); (A.R.); (F.M.); (L.V.)
- Correspondence:
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20
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Bowers MM, Whitley CT. What Drives Support for Transgender Rights? Assessing the Effects of Biological Attribution on U.S. Public Opinion of Transgender Rights. SEX ROLES 2020. [DOI: 10.1007/s11199-019-01118-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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21
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D'Andrea S, Pallotti F, Senofonte G, Castellini C, Paoli D, Lombardo F, Lenzi A, Francavilla S, Francavilla F, Barbonetti A. Polymorphic Cytosine-Adenine-Guanine Repeat Length of Androgen Receptor Gene and Gender Incongruence in Trans Women: A Systematic Review and Meta-Analysis of Case-Control Studies. J Sex Med 2020; 17:543-550. [PMID: 31926901 DOI: 10.1016/j.jsxm.2019.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/03/2019] [Accepted: 12/07/2019] [Indexed: 12/18/2022]
Abstract
INTRODUCTION It has been hypothesized that gender incongruence in transgender women could result from an antenatal impaired androgen activity on the developing brain. As the length of polymorphic cytosine-adenine-guanine (CAG) repeat sequences in the androgen receptor (AR) gene is inversely correlated with AR transcriptional activity, some studies explored a possible association between long CAG repeats and gender incongruence in trangender women. Yet results remain inconclusive. AIM To systematically evaluate whether a difference exists in the length of AR CAG repeat sequences between trans women and men without gender incongruence. METHODS A thorough search of Medline, Scopus, Cochrane Library, Web of Science, and CINAHL databases was carried out to identify suitable case-control studies. Methodological quality of the included articles was assessed using the Newcastle-Ottawa Scale. In the absence of between-studies heterogeneity, as assessed by the Cochrane's Q and I2 tests, standardized mean differences (SMDs) in the length of AR CAG repeats were combined using a fixed effect model. Funnel plot and trim-and-fill analysis were used to assess publication bias. MAIN OUTCOME MEASURE The association of gender incongruence in transgender women with longer length of AR CAG repeat sequences was evaluated by calculating pooled standardized mean difference with 95% confidence interval (CI). RESULTS 5 studies included in the quantitative analysis collectively provided information on 795 trans women and 1,355 control men. At the overall estimate, the MtF group exhibited a significantly longer length of AR CAG repeat sequences (pooled standardized mean difference: 0.13, 95% CI: 0.04 to 0.22; P = 0.005; I2 = 0%, Pfor heterogeneity = 0.51). Sensitivity analysis demonstrated the high stability of the result. Funnel plot revealed a possible publication bias, and the trim-and-fill test detected 2 putative missing studies. Nevertheless, the significant association persisted even when pooled estimate was adjusted for publication bias. CLINICAL IMPLICATIONS These findings could suggest a contribution of a genetically mediated impairment in androgen signaling in development of gender incongruence for transgender women. STRENGTH & LIMITATIONS This is the first meta-analysis exploring the relationship between AR CAG repeat polymorphism and gender incongruence. However, interactions with other functional genetic variants were not explored, and caution should be exercised when generalizing these results because of the possible variability in the distribution of CAG repeats among different populations and ethnic groups. CONCLUSION Trans woman population exhibits significantly longer polymorphic CAG repeat sequences in the AR gene. Further studies are warranted to elucidate whether, how and to what extent multiple functional variants in sex hormone signaling genes could be associated with gender incongruence/dysphoria. D'Andrea S, Pallotti F, Senofonte G, et al. Polymorphic Cytosine-Adenine-Guanine Repeat Length of Androgen Receptor Gene and Gender Incongruence in Trans Women: A Systematic Review and Meta-Analysis of Case-Control Studies. J Sex Med 2020;17:543-550.
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Affiliation(s)
- Settimio D'Andrea
- Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy
| | - Francesco Pallotti
- Department of Experimental Medicine "Sapienza", University of Rome, Rome, Italy
| | - Giulia Senofonte
- Department of Experimental Medicine "Sapienza", University of Rome, Rome, Italy
| | - Chiara Castellini
- Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy
| | - Donatella Paoli
- Department of Experimental Medicine "Sapienza", University of Rome, Rome, Italy
| | - Francesco Lombardo
- Department of Experimental Medicine "Sapienza", University of Rome, Rome, Italy
| | - Andrea Lenzi
- Department of Experimental Medicine "Sapienza", University of Rome, Rome, Italy
| | - Sandro Francavilla
- Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy
| | - Felice Francavilla
- Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy
| | - Arcangelo Barbonetti
- Andrology Unit, Department of Life, Health and Environment Sciences, University of L'Aquila, L'Aquila, Italy.
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A New Theory of Gender Dysphoria Incorporating the Distress, Social Behavioral, and Body-Ownership Networks. eNeuro 2019; 6:ENEURO.0183-19.2019. [PMID: 31792116 PMCID: PMC6911960 DOI: 10.1523/eneuro.0183-19.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/29/2019] [Accepted: 11/04/2019] [Indexed: 12/16/2022] Open
Abstract
When postmortem studies related to transgender individuals were first published, little was known about the function of the various identified nuclei. Now, over 2 decades later, significant progress has been made associating function with specific brain regions, as well as in identifying networks associated with groups of behaviors. However, much of this progress has not been integrated into the general conceptualization of gender dysphoria in humans. When postmortem studies related to transgender individuals were first published, little was known about the function of the various identified nuclei. Now, over 2 decades later, significant progress has been made associating function with specific brain regions, as well as in identifying networks associated with groups of behaviors. However, much of this progress has not been integrated into the general conceptualization of gender dysphoria in humans. I hypothesize that in individuals with gender dysphoria, the aspects of chronic distress, gender atypical behavior, and incongruence between perception of gender identity and external primary sex characteristics are all directly related to functional differences in associated brain networks. I evaluated previously published neuroscience data related to these aspects and the associated functional networks, along with other relevant information. I find that the brain networks that give individuals their ownership of body parts, that influence gender typical behavior, and that are involved in chronic distress are different in individuals with and without gender dysphoria, leading to a new theory—that gender dysphoria is a sensory perception condition, an alteration in the sense of gender influenced by the reflexive behavioral responses associated with each of these networks. This theory builds upon previous work that supports the relevance of the body-ownership network and that questions the relevance of cerebral sexual dimorphism in regard to gender dysphoria. However, my theory uses a hierarchical executive function model to incorporate multiple reflexive factors (body ownership, gender typical/atypical behavior, and chronic distress) with the cognitive, reflective process of gender identity.
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Agana MG, Greydanus DE, Indyk JA, Calles JL, Kushner J, Leibowitz S, Chelvakumar G, Cabral MD. Caring for the transgender adolescent and young adult: Current concepts of an evolving process in the 21st century. Dis Mon 2019; 65:303-356. [DOI: 10.1016/j.disamonth.2019.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Abstract
This article reviews the current literature characterizing potential factors associated with the etiologies of gender identity. The PubMed database was searched for all literature that assessed key elements affecting development of gender identity. Current models attribute gender identity etiology to endogenous biology along with prenatal androgen exposure. However, no genetic loci or specific neuroanatomic regions have been consistently identified as the single explanation for transgender identity. Although environment may play a role in gender expression, there are no data to suggest an exogenous explanation for the development of gender identity.
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Affiliation(s)
- Sira Korpaisarn
- Section of Endocrinology, Diabetes, Nutrition and Weight Management, Boston Medical Center, Boston University School of Medicine, 720 Harrison Avenue, 8th Floor, Suite 8100, Boston, MA 02118, USA.
| | - Joshua D Safer
- Center for Transgender Medicine and Surgery, Mount Sinai Health System, Icahn School of Medicine at Mount Sinai, 275 7th Avenue, Suite 1505, New York, NY 10001, USA
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Foreman M, Hare L, York K, Balakrishnan K, Sánchez FJ, Harte F, Erasmus J, Vilain E, Harley VR. Genetic Link Between Gender Dysphoria and Sex Hormone Signaling. J Clin Endocrinol Metab 2019; 104:390-396. [PMID: 30247609 DOI: 10.1210/jc.2018-01105] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/18/2018] [Indexed: 12/15/2022]
Abstract
CONTEXT There is a likely genetic component to gender dysphoria, but association study data have been equivocal. OBJECTIVE We explored the specific hypothesis that gender dysphoria in transgender women is associated with variants in sex hormone-signaling genes responsible for undermasculinization and/or feminization. DESIGN Subject-control analysis included 380 transgender women and 344 control male subjects. Associations and interactions were investigated between functional variants in 12 sex hormone-signaling genes and gender dysphoria in transgender women. SETTING Patients were recruited from the Monash Gender Clinic, Monash Health, Melbourne, Australia, and the University of California, Los Angeles. PATIENTS Caucasian (non-Latino) transgender women were recruited who received a diagnosis of transsexualism [Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV) or gender dysphoria (DSM-V)] pre- or postoperatively. Most were receiving hormone treatment at the time of recruitment. MAIN OUTCOME MEASURED Genomic DNA was genotyped for repeat length polymorphisms or single nucleotide polymorphisms. RESULTS A significant association was identified between gender dysphoria and ERα, SRD5A2, and STS alleles, as well as ERα and SULT2A1 genotypes. Several allele combinations were also overrepresented in transgender women, most involving AR (namely, AR-ERβ, AR-PGR, AR-COMT, CYP17-SRD5A2). Overrepresented alleles and genotypes are proposed to undermasculinize/feminize on the basis of their reported effects in other disease contexts. CONCLUSION Gender dysphoria may have an oligogenic component, with several genes involved in sex hormone-signaling contributing.
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Affiliation(s)
| | - Lauren Hare
- Hudson Institute of Research, Melbourne, Victoria, Australia
| | - Kate York
- Hudson Institute of Research, Melbourne, Victoria, Australia
| | | | | | - Fintan Harte
- Monash Gender Clinic, Monash Health, Melbourne, Victoria, Australia
| | | | - Eric Vilain
- Children's National Health System, Washington, DC
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Fernández R, Guillamon A, Cortés-Cortés J, Gómez-Gil E, Jácome A, Esteva I, Almaraz M, Mora M, Aranda G, Pásaro E. Molecular basis of Gender Dysphoria: androgen and estrogen receptor interaction. Psychoneuroendocrinology 2018; 98:161-167. [PMID: 30165284 DOI: 10.1016/j.psyneuen.2018.07.032] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/27/2018] [Accepted: 07/31/2018] [Indexed: 01/27/2023]
Abstract
BACKGROUND Polymorphisms in sex steroid receptors have been associated with transsexualism. However, published replication studies have yielded inconsistent findings, possibly because of a limited sample size and/or the heterogeneity of the transsexual population with respect to the onset of dysphoria and sexual orientation. We assessed the role of androgen receptor (AR), estrogen receptors alpha (ERα) and beta (ERβ), and aromatase (CYP19A1) in two large and homogeneous transsexual male-to-female (MtF) and female-to-male (FtM) populations. METHODS The association of each polymorphism with transsexualism was studied with a twofold subject-control analysis: in a homogeneous population of 549 early onset androphilic MtF transsexuals versus 728 male controls, and 425 gynephilic FtMs versus 599 female controls. Associations and interactions were investigated using binary logistic regression. RESULTS Our data show that specific allele and genotype combinations of ERβ, ERα and AR are implicated in the genetic basis of transsexualism, and that MtF gender development requires AR, which must be accompanied by ERβ. An inverse allele interaction between ERβ and AR is characteristic of the MtF population: when either of these polymorphisms is short, the other is long. ERβ and ERα are also associated with transsexualism in the FtM population although there was no interaction between the polymorphisms. Our data show that ERβ plays a key role in the typical brain differentiation of humans. CONCLUSION ERβ plays a key role in human gender differentiation in males and females.
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Affiliation(s)
- Rosa Fernández
- Departamento de Psicología, Universidade da Coruña, A Coruña, Spain.
| | - Antonio Guillamon
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, Madrid, Spain.
| | | | - Esther Gómez-Gil
- Unidad de Identidad de Género, Hospital Clínic, Barcelona, Spain.
| | - Amalia Jácome
- Departamento de Matemáticas, Universidade da Coruña, A Coruña, Spain.
| | - Isabel Esteva
- Unidad de Transexualidad e Identidad de Género, Hospital Carlos Haya, Málaga, Spain.
| | - MariCruz Almaraz
- Unidad de Transexualidad e Identidad de Género, Hospital Carlos Haya, Málaga, Spain.
| | - Mireia Mora
- Departmento de Endocrinología y Nutrición, Hospital Clínic, Barcelona, Spain.
| | - Gloria Aranda
- Departmento de Endocrinología y Nutrición, Hospital Clínic, Barcelona, Spain.
| | - Eduardo Pásaro
- Departamento de Psicología, Universidade da Coruña, A Coruña, Spain.
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Martinerie L, Condat A, Bargiacchi A, Bremont-Weill C, de Vries MC, Hannema SE. MANAGEMENT OF ENDOCRINE DISEASE: Approach to the management of children and adolescents with Gender Dysphoria. Eur J Endocrinol 2018; 179:R219-R237. [PMID: 30049812 DOI: 10.1530/eje-18-0227] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 07/07/2018] [Accepted: 07/25/2018] [Indexed: 02/03/2023]
Abstract
Over the past 20 years, the care for transgender adolescents has developed throughout many countries following the "Dutch Approach" initiated in the 90's in pioneer countries as the Netherlands, United States and Canada, with increasing numbers of children and adolescents seeking care in transgender clinics. This medical approach has considerable positive impacts on the psychological outcomes of these adolescents and several studies have been recently published underlining the relative safety of such treatments. This paper reviews the current standards of care for transgender children and adolescents with particular emphasis on disparities among countries and short to medium-term outcomes. Finally it highlights ethical considerations regarding categorization of gender dysphoria, timing of treatment initiation, infertility, and how to deal with the long-term consequences.
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Affiliation(s)
- L Martinerie
- Department of Pediatric Endocrinology, Centre de Référence des Maladies Endocriniennes Rares de la Croissance, Robert Debré Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
- Paris Diderot University, Sorbonne Paris Cité, Paris, France
- INSERM Unit 1145, Le Kremlin-Bicêtre, France
| | - A Condat
- Department of Adolescent and Child Psychiatry, Pitié-Salpétrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
- CESP INSERM 1018, ED3C, Université Paris Descartes, Paris, France
| | - A Bargiacchi
- Department of Adolescent and Child Psychiatry, Robert Debré Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - C Bremont-Weill
- Department of Endocrinology, Cochin Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - M C de Vries
- Departments of Medical Ethics and Health Law, Leiden University Medical Center, Leiden, The Netherlands
- Departments of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
| | - S E Hannema
- Departments of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands
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Pierce JP. Transthesia: Comparing the Prevalence of Synesthesia in Transgender and Cisgender Individuals. Transgend Health 2018; 3:154-158. [PMID: 30182062 PMCID: PMC6118196 DOI: 10.1089/trgh.2018.0010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Purpose: To evaluate the prevalence of synesthesia in transgender versus cisgender individuals. Methods: A 10-question, self-administered written survey, developed to assess the prevalence of synesthesia, was distributed to transgender individuals (n=96) attending support groups as well as to cisgender participants (n=103) identified among individuals accompanying transgender attendees. Demographic data and prevalence of synesthesia were analyzed using descriptive statistics. Differences between groups were analyzed using a chi-square test. Results: Forty-two percent of transgender participants endorsed synesthesia compared with 16% of cisgender participants. These findings persisted when analyzed by specific gender identity (i.e., male, female, and nonbinary). Conclusion: This study suggests a correlation between synesthesia and transgender identity that may indicate a common biological cause. Limitations of this study include use of a survey that has not yet been validated. Initial findings may justify further research.
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Affiliation(s)
- Jay P Pierce
- Student, Ballard High School, Seattle, Washington
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29
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Pang KC, Feldman D, Oertel R, Telfer M. Molecular Karyotyping in Children and Adolescents with Gender Dysphoria. Transgend Health 2018; 3:147-153. [PMID: 30094339 PMCID: PMC6083207 DOI: 10.1089/trgh.2017.0051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Purpose: The presence of a disorder of sexual development (DSD) acts as a diagnostic specifier for gender dysphoria (GD) under DSM-5, while the International Classification of Diseases (ICD)-10 specifically states that its equivalent diagnosis, gender identity disorder (GID), must not be the result of a chromosomal abnormality. For these reasons, routine karyotyping has been previously advocated in the clinical work-up of children and adolescents with suspected GD or GID. However, the utility of such testing remains unclear. Methods: The results of routine molecular karyotyping were analyzed in 128 patients attending our Australian statewide pediatric gender service from 2013 to 2016. Karyotyping was performed using an Illumina BeadChip platform and provided information on both sex chromosome composition and copy number variation (CNV). Results: No sex chromosome abnormalities directly suggestive of a DSD were discovered. The rate of CNVs among our patient cohort was 8.6% (11/128), similar to that previously reported for the general population. Unexpectedly, three trans male patients shared the same CNV, involving an almost identical 400 kbp deletion on chromosome 15q11.2. The frequency of this deletion within birth-assigned females in our cohort (3/69; 4.3%) was significantly higher than that within local control populations (0.3%; Fisher's exact test p-value=0.002), suggesting a possible association between 15q11.2 deletions and trans male identity. Conclusion: Routine molecular karyotyping failed to detect any occult DSD and indicated that the rate of CNVs was similar to that of the general population. Given these findings, we suggest that molecular karyotyping has minimal clinical utility in the routine management of children and adolescents with GD.
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Affiliation(s)
- Ken C Pang
- Department of Adolescent Medicine, Royal Children's Hospital, Parkville, Australia.,Murdoch Children's Research Institute, Parkville, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Australia.,Department of Psychiatry, University of Melbourne, Parkville, Australia.,The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
| | - Debi Feldman
- Department of Adolescent Medicine, Royal Children's Hospital, Parkville, Australia.,Murdoch Children's Research Institute, Parkville, Australia
| | - Ralph Oertel
- Victorian Clinical Genetics Service, Parkville, Australia
| | - Michelle Telfer
- Department of Adolescent Medicine, Royal Children's Hospital, Parkville, Australia.,Murdoch Children's Research Institute, Parkville, Australia.,Department of Paediatrics, University of Melbourne, Parkville, Australia
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30
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Roselli CE. Neurobiology of gender identity and sexual orientation. J Neuroendocrinol 2018; 30:e12562. [PMID: 29211317 PMCID: PMC6677266 DOI: 10.1111/jne.12562] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/03/2017] [Accepted: 11/28/2017] [Indexed: 12/15/2022]
Abstract
Sexual identity and sexual orientation are independent components of a person's sexual identity. These dimensions are most often in harmony with each other and with an individual's genital sex, although not always. The present review discusses the relationship of sexual identity and sexual orientation to prenatal factors that act to shape the development of the brain and the expression of sexual behaviours in animals and humans. One major influence discussed relates to organisational effects that the early hormone environment exerts on both gender identity and sexual orientation. Evidence that gender identity and sexual orientation are masculinised by prenatal exposure to testosterone and feminised in it absence is drawn from basic research in animals, correlations of biometric indices of androgen exposure and studies of clinical conditions associated with disorders in sexual development. There are, however, important exceptions to this theory that have yet to be resolved. Family and twin studies indicate that genes play a role, although no specific candidate genes have been identified. Evidence that relates to the number of older brothers implicates maternal immune responses as a contributing factor for male sexual orientation. It remains speculative how these influences might relate to each other and interact with postnatal socialisation. Nonetheless, despite the many challenges to research in this area, existing empirical evidence makes it clear that there is a significant biological contribution to the development of an individual's sexual identity and sexual orientation.
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Affiliation(s)
- C E Roselli
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA
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31
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Fisher AD, Ristori J, Morelli G, Maggi M. The molecular mechanisms of sexual orientation and gender identity. Mol Cell Endocrinol 2018; 467:3-13. [PMID: 28847741 DOI: 10.1016/j.mce.2017.08.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/02/2017] [Accepted: 08/15/2017] [Indexed: 12/21/2022]
Abstract
Differences between males and females are widely represented in nature. There are gender differences in phenotypes, personality traits, behaviors and interests, cognitive performance, and proneness to specific diseases. The most marked difference in humans is represented by sexual orientation and core gender identity, the origins of which are still controversial and far from being understood. Debates continue on whether sexual behavior and gender identity are a result of biological (nature) or cultural (nurture) factors, with biology possibly playing a major role. The main goal of this review is to summarize the studies available to date on the biological factors involved in the development of both sexual orientation and gender identity. A systematic search of published evidence was performed using Medline (from January 1948 to June 2017). Review of the relevant literature was based on authors' expertise. Indeed, different studies have documented the possible role and interaction of neuroanatomic, hormonal and genetic factors. The sexual dimorphic brain is considered the anatomical substrate of psychosexual development, on which genes and gonadal hormones may have a shaping effect. In particular, growing evidence shows that prenatal and pubertal sex hormones permanently affect human behavior. In addition, heritability studies have demonstrated a role of genetic components. However, a convincing candidate gene has not been identified. Future studies (e.i. genome wide studies) are needed to better clarify the complex interaction between genes, anatomy and hormonal influences on psychosexual development.
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Affiliation(s)
- Alessandra D Fisher
- Department of Experimental, Clinical and Biomedical Sciences, Careggi University Hospital, Florence, Italy
| | - Jiska Ristori
- Department of Experimental, Clinical and Biomedical Sciences, Careggi University Hospital, Florence, Italy
| | - Girolamo Morelli
- Department of Surgical, Medical, Molecular and of the Critical Area Pathology, University of Pisa, Pisa, Italy
| | - Mario Maggi
- Department of Experimental, Clinical and Biomedical Sciences, Careggi University Hospital, Florence, Italy.
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Fernández R, Guillamón A, Gómez-Gil E, Esteva I, Almaraz MC, Cortés-Cortés J, Lamas B, Lema E, Pásaro E. Analyses of karyotype by G-banding and high-resolution microarrays in a gender dysphoria population. Genes Genomics 2018; 40:465-473. [DOI: 10.1007/s13258-017-0646-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 12/29/2017] [Indexed: 12/31/2022]
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The Sexual Differentiation of the Human Brain: Role of Sex Hormones Versus Sex Chromosomes. Curr Top Behav Neurosci 2018; 43:45-67. [PMID: 30599078 DOI: 10.1007/7854_2018_70] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Men and women differ, not only in their anatomy but also in their behavior. Research using animal models has convincingly shown that sex differences in the brain and behavior are induced by sex hormones during a specific, hormone-sensitive period during early development. Thus, male-typical psychosexual characteristics seem to develop under the influence of testosterone, mostly acting during early development. By contrast, female-typical psychosexual characteristics may actually be organized under the influence of estradiol during a specific prepubertal period. The sexual differentiation of the human brain also seems to proceed predominantly under the influence of sex hormones. Recent studies using magnetic resonance imaging have shown that several sexually differentiated aspects of brain structure and function are female-typical in women with complete androgen insensitivity syndrome (CAIS), who have a 46 XY karyotype but a female phenotype due to complete androgen resistance, suggesting that these sex differences most likely reflect androgen action, although feminizing effects of estrogens or female-typical socialization cannot be ruled out. By contrast, some male-typical neural characteristics were also observed in women with CAIS suggesting direct effects of sex chromosome genes in the sexual differentiation of the human brain. In conclusion, the sexual differentiation of the human brain is most likely a multifactorial process including both sex hormone and sex chromosome effects, acting in parallel or in combination.
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Hembree WC, Cohen-Kettenis PT, Gooren L, Hannema SE, Meyer WJ, Murad MH, Rosenthal SM, Safer JD, Tangpricha V, T'Sjoen GG. Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 2017; 102:3869-3903. [PMID: 28945902 DOI: 10.1210/jc.2017-01658] [Citation(s) in RCA: 1146] [Impact Index Per Article: 163.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/24/2017] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To update the "Endocrine Treatment of Transsexual Persons: An Endocrine Society Clinical Practice Guideline," published by the Endocrine Society in 2009. PARTICIPANTS The participants include an Endocrine Society-appointed task force of nine experts, a methodologist, and a medical writer. EVIDENCE This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies. CONSENSUS PROCESS Group meetings, conference calls, and e-mail communications enabled consensus. Endocrine Society committees, members and cosponsoring organizations reviewed and commented on preliminary drafts of the guidelines. CONCLUSION Gender affirmation is multidisciplinary treatment in which endocrinologists play an important role. Gender-dysphoric/gender-incongruent persons seek and/or are referred to endocrinologists to develop the physical characteristics of the affirmed gender. They require a safe and effective hormone regimen that will (1) suppress endogenous sex hormone secretion determined by the person's genetic/gonadal sex and (2) maintain sex hormone levels within the normal range for the person's affirmed gender. Hormone treatment is not recommended for prepubertal gender-dysphoric/gender-incongruent persons. Those clinicians who recommend gender-affirming endocrine treatments-appropriately trained diagnosing clinicians (required), a mental health provider for adolescents (required) and mental health professional for adults (recommended)-should be knowledgeable about the diagnostic criteria and criteria for gender-affirming treatment, have sufficient training and experience in assessing psychopathology, and be willing to participate in the ongoing care throughout the endocrine transition. We recommend treating gender-dysphoric/gender-incongruent adolescents who have entered puberty at Tanner Stage G2/B2 by suppression with gonadotropin-releasing hormone agonists. Clinicians may add gender-affirming hormones after a multidisciplinary team has confirmed the persistence of gender dysphoria/gender incongruence and sufficient mental capacity to give informed consent to this partially irreversible treatment. Most adolescents have this capacity by age 16 years old. We recognize that there may be compelling reasons to initiate sex hormone treatment prior to age 16 years, although there is minimal published experience treating prior to 13.5 to 14 years of age. For the care of peripubertal youths and older adolescents, we recommend that an expert multidisciplinary team comprised of medical professionals and mental health professionals manage this treatment. The treating physician must confirm the criteria for treatment used by the referring mental health practitioner and collaborate with them in decisions about gender-affirming surgery in older adolescents. For adult gender-dysphoric/gender-incongruent persons, the treating clinicians (collectively) should have expertise in transgender-specific diagnostic criteria, mental health, primary care, hormone treatment, and surgery, as needed by the patient. We suggest maintaining physiologic levels of gender-appropriate hormones and monitoring for known risks and complications. When high doses of sex steroids are required to suppress endogenous sex steroids and/or in advanced age, clinicians may consider surgically removing natal gonads along with reducing sex steroid treatment. Clinicians should monitor both transgender males (female to male) and transgender females (male to female) for reproductive organ cancer risk when surgical removal is incomplete. Additionally, clinicians should persistently monitor adverse effects of sex steroids. For gender-affirming surgeries in adults, the treating physician must collaborate with and confirm the criteria for treatment used by the referring physician. Clinicians should avoid harming individuals (via hormone treatment) who have conditions other than gender dysphoria/gender incongruence and who may not benefit from the physical changes associated with this treatment.
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Affiliation(s)
- Wylie C Hembree
- New York Presbyterian Hospital, Columbia University Medical Center, New York, New York 10032
| | | | - Louis Gooren
- VU University Medical Center, 1007 MB Amsterdam, Netherlands
| | | | - Walter J Meyer
- University of Texas Medical Branch, Galveston, Texas 77555
| | - M Hassan Murad
- Mayo Clinic Evidence-Based Practice Center, Rochester, Minnesota 55905
| | - Stephen M Rosenthal
- University of California San Francisco, Benioff Children's Hospital, San Francisco, California 94143
| | - Joshua D Safer
- Boston University School of Medicine, Boston, Massachusetts 02118
| | - Vin Tangpricha
- Emory University School of Medicine and the Atlanta VA Medical Center, Atlanta, Georgia 30322
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Meagher T, Filzmaier K. The Medical Underwriting of Transgender Individuals. J Insur Med 2017; 47:43-49. [PMID: 28836906 DOI: 10.17849/insm-47-01-43-49.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
As more transgender individuals apply for life insurance, it is important to understand the many health issues that are particular to this population. This article reviews the pathophysiology, diagnosis and treatment of gender dysphoria- the dominant medical problem of transgender individuals. It also reviews the frequent co-morbidities in the transgender population and finishes with a review of the small number of studies that have examined long-term mortality.
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Affiliation(s)
- Timothy Meagher
- Meagher- Vice-President and Medical Director, Munich Re, Montréal; Associate Professor of Medicine, McGill University, Montréal, Québec; Filzmaier- Head of Center of Competence Medical Research & Consulting, Munich Re, Munich, Germany
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36
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Yang F, Zhu XH, Zhang Q, Sun NX, Ji YX, Ma JZ, Xiao B, Ding HX, Sun SH, Li W. Genomic Characteristics of Gender Dysphoria Patients and Identification of Rare Mutations in RYR3 Gene. Sci Rep 2017; 7:8339. [PMID: 28827537 PMCID: PMC5567086 DOI: 10.1038/s41598-017-08655-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/14/2017] [Indexed: 11/26/2022] Open
Abstract
Gender dysphoria (GD) is characterized by an incongruence between the gender assigned at birth and the gender with which one identifies. The biological mechanisms of GD are unclear. While common genetic variants are associated with GD, positive findings have not always been replicated. To explore the role of rare variants in GD susceptibility within the Han Chinese population, whole-genome sequencing of 9 Han female-to-male transsexuals (FtMs) and whole-exome sequencing of 4 Han male-to-female transsexuals (MtFs) were analyzed using a pathway burden analysis in which variants are first collapsed at the gene level and then by Gene Ontology terms. Novel nonsynonymous variants in ion transport genes were significantly enriched in FtMs (P- value, 2.41E-10; Fold enrichment, 2.8) and MtFs (P- value, 1.04E-04; Fold enrichment, 2.3). Gene burden analysis comparing 13 GD cases and 100 controls implicated RYR3, with three heterozygous damaging mutations in unrelated FtMs and zero in controls (P = 0.001). Importantly, protein structure modeling of the RYR3 mutations indicated that the R1518H mutation made a large structural change in the RYR3 protein. Overall, our results provide information about the genetic basis of GD.
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Affiliation(s)
- Fu Yang
- Department of Medical Genetics, Second Military Medical University, Shanghai, 200433, China.
| | - Xiao-Hai Zhu
- Department of Plastic Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, 200433, China
| | - Qing Zhang
- Center of Reproductive Medicine, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Ning-Xia Sun
- Center of Reproductive Medicine, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Yi-Xuan Ji
- Center of Reproductive Medicine, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Jin-Zhao Ma
- Department of Medical Genetics, Second Military Medical University, Shanghai, 200433, China
| | - Bang Xiao
- Department of Medical Genetics, Second Military Medical University, Shanghai, 200433, China
| | - Hai-Xia Ding
- Center of Reproductive Medicine, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China
| | - Shu-Han Sun
- Department of Medical Genetics, Second Military Medical University, Shanghai, 200433, China.
| | - Wen Li
- Center of Reproductive Medicine, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, 200003, China.
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37
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Irwig MS. Testosterone therapy for transgender men. Lancet Diabetes Endocrinol 2017; 5:301-311. [PMID: 27084565 DOI: 10.1016/s2213-8587(16)00036-x] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 01/02/2016] [Accepted: 01/18/2016] [Indexed: 01/03/2023]
Abstract
Testosterone therapy is a cornerstone of medical treatment for transgender men who choose to undergo it. The goal of testosterone therapy is usually to achieve serum testosterone concentrations in the male reference range. Testosterone has several desired effects as well as undesired and unknown effects. The desired effects include increased facial and body hair, increased lean mass and strength, decreased fat mass, deepening of the voice, increased sexual desire, cessation of menstruation, clitoral enlargement, and reductions in gender dysphoria, perceived stress, anxiety, and depression. Achievement of these goals comes with potential undesired effects and risks including acne, alopecia, reduced HDL cholesterol, increased triglycerides, and a possible increase in systolic blood pressure. An additional benefit of testosterone therapy (with or without mastectomy) is a reduced risk of breast cancer. Most of the effects of testosterone start to develop within several months of starting therapy, although facial hair and alopecia continue to develop after 1 year. A major limitation in the study of testosterone therapy for transgender men is a paucity of high-quality data due to a shortage of randomised controlled trials (partly because of ethical issues), few prospective and long-term studies, the use of suboptimum control groups, loss to follow-up, and difficulties in recruitment of representative samples of transgender populations.
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Affiliation(s)
- Michael S Irwig
- Center for Andrology and Division of Endocrinology, George Washington University, Washington, DC, USA.
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Genotypes and Haplotypes of the Estrogen Receptor α Gene ( ESR1 ) Are Associated With Female-to-Male Gender Dysphoria. J Sex Med 2017; 14:464-472. [DOI: 10.1016/j.jsxm.2016.12.234] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 12/16/2016] [Accepted: 12/21/2016] [Indexed: 11/23/2022]
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Abstract
In many countries throughout the world, increasing numbers of gender nonconforming/transgender youth are seeking medical services to enable the development of physical characteristics consistent with their experienced gender. Such medical services include use of agents to block endogenous puberty at Tanner stage II with subsequent use of cross-sex hormones, and are based on longitudinal studies demonstrating that those individuals who were first identified as gender dysphoric in early or middle childhood and continue to meet the mental health criteria for being transgender at early puberty are likely to be transgender as adults. This review addresses terms and definitions applicable to gender nonconforming youth, studies that shed light on the biologic determinants of gender identity, current clinical practice guidelines for transgender youth, challenges to optimal care, and priorities for research.
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Affiliation(s)
- Stephen M. Rosenthal
- Division of Pediatric Endocrinology, Child and Adolescent Gender Center, Benioff Children's Hospital, University of California San Francisco, San Francisco, CA, USA
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40
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Fisher AD, Ristori J, Fanni E, Castellini G, Forti G, Maggi M. Gender identity, gender assignment and reassignment in individuals with disorders of sex development: a major of dilemma. J Endocrinol Invest 2016; 39:1207-1224. [PMID: 27287420 DOI: 10.1007/s40618-016-0482-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 05/04/2016] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Disorders of Sex Development (DSD) are a wide range of congenital conditions characterized by an incongruence of components involved in sexual differentiation, including gender psychosexual development. The management of such disorders is complex, and one of the most crucial decision is represented by gender assignment. In fact, the primary goal in DSD is to have a gender assignment consistent with the underlying gender identity in order to prevent the distress related to a forthcoming Gender Dysphoria. Historically, gender assignment was based essentially on surgical outcomes, assuming the neutrality of gender identity at birth. This policy has been challenged in the past decade refocusing on the importance of prenatal and postnatal hormonal and genetic influences on psychosexual development. AIMS (1) to update the main psychological and medical issues that surround DSD, in particular regarding gender identity and gender assignment; (2) to report specific clinical recommendations according to the different diagnosis. METHODS A systematic search of published evidence was performed using Medline (from 1972 to March 2016). Review of the relevant literature and recommendations was based on authors' expertise. RESULTS A review of gender identity and assignment in DSD is provided as well as clinical recommendations for the management of individuals with DSD. CONCLUSIONS Given the complexity of this management, DSD individuals and their families need to be supported by a specialized multidisciplinary team, which has been universally recognized as the best practice for intersexual conditions. In case of juvenile GD in DSD, the prescription of gonadotropin-releasing hormone analogues, following the World Professional Association for Transgender Health and the Endocrine Society guidelines, should be considered. It should always be taken into account that every DSD person is unique and has to be treated with individualized care. In this perspective, international registries are crucial to improve the understanding of these challenging conditions and clinical practice, in providing a better prediction of gender identity.
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Affiliation(s)
- A D Fisher
- Sexual Medicine and Andrology Unit, Department of Experimental, Clinical and Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy
| | - J Ristori
- Sexual Medicine and Andrology Unit, Department of Experimental, Clinical and Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy
| | - E Fanni
- Sexual Medicine and Andrology Unit, Department of Experimental, Clinical and Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy
| | - G Castellini
- Sexual Medicine and Andrology Unit, Department of Experimental, Clinical and Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy
- Psychiatric Unit, Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - G Forti
- Endocrine Unit, "Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies" (DENOThe), Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Careggi Hospital, Florence, Italy
| | - M Maggi
- Sexual Medicine and Andrology Unit, Department of Experimental, Clinical and Biomedical Sciences, University of Florence, Viale Pieraccini 6, 50139, Florence, Italy.
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Abstract
The current review gives an overview of brain studies in transgender people. First, we describe studies into the aetiology of feelings of gender incongruence, primarily addressing the sexual differentiation hypothesis: does the brain of transgender individuals resemble that of their natal sex, or that of their experienced gender? Findings from neuroimaging studies focusing on brain structure suggest that the brain phenotypes of trans women (MtF) and trans men (FtM) differ in various ways from control men and women with feminine, masculine, demasculinized and defeminized features. The brain phenotypes of people with feelings of gender incongruence may help us to figure out whether sex differentiation of the brain is atypical in these individuals, and shed light on gender identity development. Task-related imaging studies may show whether brain activation and task performance in transgender people is sex-atypical. Second, we review studies that evaluate the effects of cross-sex hormone treatment on the brain. This type of research provides knowledge on how changes in sex hormone levels may affect brain structure and function.
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Affiliation(s)
- Baudewijntje P C Kreukels
- a VU University Medical Centre, Department of Medical Psychology, Centre of Expertise on Gender Dysphoria, EMGO Institute for Health and Care Research , Amsterdam , the Netherlands
| | - Antonio Guillamon
- b Universidad Nacional de Educacion a Distancia (UNED) , Departamento de Psicobiologia , Madrid , Spain
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Sasaki S, Ozaki K, Yamagata S, Takahashi Y, Shikishima C, Kornacki T, Nonaka K, Ando J. Genetic and Environmental Influences on Traits of Gender Identity Disorder: A Study of Japanese Twins Across Developmental Stages. ARCHIVES OF SEXUAL BEHAVIOR 2016; 45:1681-1695. [PMID: 27507021 DOI: 10.1007/s10508-016-0821-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 04/28/2016] [Accepted: 07/19/2016] [Indexed: 06/06/2023]
Abstract
The present study examined: (1) gender and age differences of mean gender identity disorder (GID) trait scores in Japanese twins; (2) the validity of the prenatal hormone transfer theory, which predicts that, in dizygotic (DZ) twin pairs, twins with an opposite-gender co-twin more frequently exhibit GID traits than twins with a same-gender co-twin; and (3) the magnitude of genetic and environmental influences on GID traits as a function of age and gender. Data from 1450 male twin pairs, 1882 female twin pairs, and 1022 DZ male-female pairs ranging from 3 to 26 years of age were analyzed. To quantify individual variances in GID traits, each participant completed four questionnaire items based on criteria for GID from the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Our most important findings were: (1) Japanese females exhibited GID traits more frequently than males and Japanese children exhibited GID traits less frequently than adolescents and adults (among females, the prevalence was 1.6 % in children, 10 % in adolescents, and 12 % in adults; among males, the prevalence was 0.5, 2, and 3 %, respectively); (2) the data did not support the prenatal hormone transfer theory for GID traits; and (3) a large part of the variance for GID traits in children was accounted for by familial factors; however, the magnitude was found to be greater in children than in adolescents or adults, particularly among females. This study suggests that although the prevalence is likely to increase, familial effects are likely to decrease as individuals age.
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Affiliation(s)
- Shoko Sasaki
- Department of Contemporary Communication, St. Margaret's Junior College, 4-29-60, Kugayama, Suginami-Ku, Tokyo, 168-8616, Japan.
| | - Koken Ozaki
- Graduate School of Business Sciences, University of Tsukuba, Tokyo, Japan
| | - Shinji Yamagata
- Faculty of Arts and Science, Kyushu University, Fukuoka, Japan
| | | | | | - Tamara Kornacki
- Ontario Institute for Studies in Education, University of Toronto, Toronto, ON, Canada
| | - Koichi Nonaka
- Faculty of Human Sciences, Department of Human and Environmental Well-being, Wako University, Tokyo, Japan
| | - Juko Ando
- Faculty of Letters, Keio University, Tokyo, Japan
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Guillamon A, Junque C, Gómez-Gil E. A Review of the Status of Brain Structure Research in Transsexualism. ARCHIVES OF SEXUAL BEHAVIOR 2016; 45:1615-48. [PMID: 27255307 PMCID: PMC4987404 DOI: 10.1007/s10508-016-0768-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/22/2015] [Accepted: 04/29/2016] [Indexed: 05/22/2023]
Abstract
The present review focuses on the brain structure of male-to-female (MtF) and female-to-male (FtM) homosexual transsexuals before and after cross-sex hormone treatment as shown by in vivo neuroimaging techniques. Cortical thickness and diffusion tensor imaging studies suggest that the brain of MtFs presents complex mixtures of masculine, feminine, and demasculinized regions, while FtMs show feminine, masculine, and defeminized regions. Consequently, the specific brain phenotypes proposed for MtFs and FtMs differ from those of both heterosexual males and females. These phenotypes have theoretical implications for brain intersexuality, asymmetry, and body perception in transsexuals as well as for Blanchard's hypothesis on sexual orientation in homosexual MtFs. Falling within the aegis of the neurohormonal theory of sex differences, we hypothesize that cortical differences between homosexual MtFs and FtMs and male and female controls are due to differently timed cortical thinning in different regions for each group. Cross-sex hormone studies have reported marked effects of the treatment on MtF and FtM brains. Their results are used to discuss the early postmortem histological studies of the MtF brain.
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Affiliation(s)
- Antonio Guillamon
- Departamento de Psicobiología, Universidad Nacional de Educación a Distancia, c/Juand del Rosal, 10, 28040, Madrid, Spain.
- Academia de Psicología de España, Madrid, Spain.
| | - Carme Junque
- Departamento de Psiquiatría y Psicobiología Clínica, Universidad de Barcelona, Barcelona, Spain
- Institute of Biomedical Research August Pi i Sunyer, Barcelona, Spain
| | - Esther Gómez-Gil
- Institute of Biomedical Research August Pi i Sunyer, Barcelona, Spain
- Unidad de Identidad de Género, Hospital Clinic, Barcelona, Spain
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44
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Abstract
OBJECTIVE To review current literature that supports a biologic basis of gender identity. METHODS A traditional literature review. RESULTS Evidence that there is a biologic basis for gender identity primarily involves (1) data on gender identity in patients with disorders of sex development (DSDs, also known as differences of sex development) along with (2) neuroanatomical differences associated with gender identity. CONCLUSIONS Although the mechanisms remain to be determined, there is strong support in the literature for a biologic basis of gender identity.
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Affiliation(s)
- Aruna Saraswat
- Section of Endocrinology, Diabetes and Nutrition, Boston Medical Center, Boston University School of Medicine
| | | | - Joshua D Safer
- Section of Endocrinology, Diabetes and Nutrition, Boston Medical Center, Boston University School of Medicine Section of Endocrinology, Diabetes and Nutrition, Boston University School of Medicine
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45
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Abstract
In this paper we examine the social and legal conditions in which many transgender people (often called trans people) live, and the medical perspectives that frame the provision of health care for transgender people across much of the world. Modern research shows much higher numbers of transgender people than were apparent in earlier clinic-based studies, as well as biological factors associated with gender incongruence. We examine research showing that many transgender people live on the margins of society, facing stigma, discrimination, exclusion, violence, and poor health. They often experience difficulties accessing appropriate health care, whether specific to their gender needs or more general in nature. Some governments are taking steps to address human rights issues and provide better legal protection for transgender people, but this action is by no means universal. The mental illness perspective that currently frames health-care provision for transgender people across much of the world is under scrutiny. The WHO diagnostic manual may soon abandon its current classification of transgender people as mentally disordered. Debate exists as to whether there should be a diagnosis of any sort for transgender children below the age of puberty.
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Affiliation(s)
- Sam Winter
- School of Public Health, Faculty of Health Sciences, Curtin University, Perth, WA, Australia.
| | - Milton Diamond
- Pacific Center for Sex and Society, John A Burns School of Medicine, University of Hawai'i, Manoa, HI, USA
| | - Jamison Green
- California Institute of Integral Studies, San Francisco, CA, USA
| | - Dan Karasic
- Department of Psychiatry, University of California and San Francisco, San Francisco, CA, USA
| | - Terry Reed
- Gender Identity Research and Education Society, Ashtead, UK
| | - Stephen Whittle
- School of Law, Manchester Metropolitan University, Manchester, UK
| | - Kevan Wylie
- Porterbrook Clinic and Royal Hallamshire Hospital, Sheffield, UK
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Pakpoor J, Wotton CJ, Schmierer K, Giovannoni G, Goldacre MJ. Gender identity disorders and multiple sclerosis risk: A national record-linkage study. Mult Scler 2016; 22:1759-1762. [DOI: 10.1177/1352458515627205] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 12/23/2015] [Indexed: 11/17/2022]
Abstract
Background: An altered balance of gonadal hormones in males with gender identity disorders (GIDs) may increase multiple sclerosis (MS) risk both inherently and secondary to treatment in undergoing male-to-female conversion. Objective: We investigated any association between GIDs and MS through analysis of record-linked hospital statistics. Method: Analysis of English Hospital Episode Statistics, 1999–2012. Results: The adjusted rate ratio (RR) of MS following GIDs in males was 6.63 (95% confidence interval (95% CI) = 1.81–17.01, p = 0.0002). The RR of MS following GIDs in females was 1.44 (95% CI = 0.47–3.37, p = 0.58). Conclusion: We report a strong association between GIDs and MS in male-to-females, supporting a potential role for low testosterone and/or feminising hormones on MS risk in males.
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Affiliation(s)
- Julia Pakpoor
- Unit of Health-Care Epidemiology, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Clare J Wotton
- Unit of Health-Care Epidemiology, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Klaus Schmierer
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London, UK; Department of Neurology, Barts Health NHS Trust, The Royal London Hospital, London, UK
| | - Gavin Giovannoni
- Blizard Institute, Barts and The London School of Medicine and Dentistry, Queen Mary, University of London, London, UK; Department of Neurology, Barts Health NHS Trust, The Royal London Hospital, London, UK
| | - Michael J Goldacre
- Unit of Health-Care Epidemiology, Nuffield Department of Population Health, University of Oxford, Oxford, UK
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48
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Abstract
Transgender individuals experience unique challenges with regards to discrimination and access to health care. Further, their unique health-care needs and challenges lead to greater rates of morbidity. This article seeks to review the unique biology of transgender patients and the effects of cross-sex hormone therapy on ophthalmic and non-ophthalmic pathology. Attention is given to topics in neuro-ophthalmology, oculoplastics, and retinal disease.
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Affiliation(s)
- Matthew W Hollar
- a Department of Ophthalmology and Visual Sciences , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Matthew M Zhang
- a Department of Ophthalmology and Visual Sciences , Vanderbilt University Medical Center , Nashville , TN , USA
| | - Louise A Mawn
- a Department of Ophthalmology and Visual Sciences , Vanderbilt University Medical Center , Nashville , TN , USA.,b Department of Neurological Surgery , Vanderbilt University Medical Center , Nashville , TN , USA
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49
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Abstract
Gender dysphoria (GD), a term that denotes persistent discomfort with one's biologic sex or assigned gender, replaced the diagnosis of gender identity disorder in the Diagnostic and Statistical Manual of Mental Disorders in 2013. Subtypes of GD in adults, defined by sexual orientation and age of onset, have been described; these display different developmental trajectories and prognoses. Prevalence studies conclude that fewer than 1 in 10,000 adult natal males and 1 in 30,000 adult natal females experience GD, but such estimates vary widely. GD in adults is associated with an elevated prevalence of comorbid psychopathology, especially mood disorders, anxiety disorders, and suicidality. Causal mechanisms in GD are incompletely understood, but genetic, neurodevelopmental, and psychosocial factors probably all contribute. Treatment of GD in adults, although largely standardized, is likely to evolve in response to the increasing diversity of persons seeking treatment, demands for greater client autonomy, and improved understanding of the benefits and limitations of current treatment modalities.
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Affiliation(s)
- Kenneth J Zucker
- Gender Identity Clinic, Child, Youth, and Family Services, Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada;
| | - Anne A Lawrence
- Department of Psychology, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Baudewijntje P C Kreukels
- Department of Medical Psychology, VU University Medical Center and EMGO Institute for Health and Care Research, Amsterdam 1081 HV, The Netherlands
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50
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Smith ES, Junger J, Derntl B, Habel U. The transsexual brain – A review of findings on the neural basis of transsexualism. Neurosci Biobehav Rev 2015; 59:251-66. [DOI: 10.1016/j.neubiorev.2015.09.008] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 09/18/2015] [Accepted: 09/20/2015] [Indexed: 12/30/2022]
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