Estradiol-driven metabolism in transwomen associates with reduced circulating extracellular vesicle microRNA-224/452

OBJECTIVE

Sex steroid hormones like estrogens have a key role in the regulation of energy homeostasis and metabolism. In transwomen, gender-affirming hormone therapy like estradiol (in combination with antiandrogenic compounds) could affect metabolism as well. Given that the underlying pathophysiological mechanisms are not fully understood, this study assessed circulating estradiol-driven microRNAs (miRs) in transwomen and their regulation of genes involved in metabolism in mice.

METHODS

Following plasma miR-sequencing (seq) in a transwomen discovery (n = 20) and validation cohort (n = 30), we identified miR-224 and miR-452. Subsequent systemic silencing of these miRs in male C57Bl/6 J mice (n = 10) was followed by RNA-seq-based gene expression analysis of brown and white adipose tissue in conjunction with mechanistic studies in cultured adipocytes.

RESULTS

Estradiol in transwomen lowered plasma miR-224 and -452 carried in extracellular vesicles (EVs) while their systemic silencing in mice and cultured adipocytes increased lipogenesis (white adipose) but reduced glucose uptake and mitochondrial respiration (brown adipose). In white and brown adipose tissue, differentially expressed (miR target) genes are associated with lipogenesis (white adipose) and mitochondrial respiration and glucose uptake (brown adipose).

CONCLUSION

This study identified an estradiol-drive post-transcriptional network that could potentially offer a mechanistic understanding of metabolism following gender-affirming estradiol therapy.

17α-ethynylestradiol prevents the natural male-to-female sex change in gilthead seabream (Sparus aurata L.)

Exposure to 17α-ethynylestradiol (EE2, 5 μg/g food) impairs some reproductive events in the protandrous gilthead seabream and a short recovery period does not allow full recovery. In this study, spermiating seabream males in the second reproductive cycle (RC) were fed a diet containing 5 or 2.5 μg EE2/g food for 28 days and then a commercial diet without EE2 for the remaining RC. Individuals were sampled at the end of the EE2 treatment and then at the end of the RC and at the beginning of the third RC, 146 and 333 days after the cessation of treatment, respectively. Increased hepatic transcript levels of the gene coding for vitellogenin (vtg) and plasma levels of Vtg indicated both concentrations of EE2 caused endocrine disruption. Modifications in the histological organization of the testis, germ cell proliferation, plasma levels of the sex steroids and pituitary expression levels of the genes coding for the gonadotropin β-subunits, fshβ and lhβ were detected. The plasma levels of Vtg and most of the reproductive parameters were restored 146 days after treatments. However, although 50% of the control fish underwent sex reversal as expected at the third RC, male-to female sex change was prevented by both EE2 concentrations.

Breast Cancer and Major Deviations of Genetic and Gender-related Structures and Function

We have searched the literature for information on the risk of breast cancer (BC) in relation to gender, breast development, and gonadal function in the following 8 populations: 1) females with the Turner syndrome (45, XO); 2) females and males with congenital hypogonadotropic hypogonadism and the Kallmann syndrome; 3) pure gonadal dysgenesis (PGD) in genotypic and phenotypic females and genotypic males (Swyer syndrome); 4) males with the Klinefelter syndrome (47, XXY); 5) male-to-female transgender individuals; 6) female-to-male transgender individuals; 7) genotypic males, but phenotypic females with the complete androgen insensitivity syndrome, and 8) females with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome (müllerian agenesis). Based on this search, we have drawn 3 major conclusions. First, the presence of a Y chromosome protects against the development of BC, even when female-size breasts and female-level estrogens are present. Second, without menstrual cycles, BC hardly occurs with an incidence comparable to males. There is a strong correlation between the lifetime number of menstrual cycles and the risk of BC. In our populations the BC risk in genetic females not exposed to progesterone (P4) is very low and comparable to males. Third, BC has been reported only once in genetic females with MRKH syndrome who have normal breasts and ovulating ovaries with normal levels of estrogens and P4. We hypothesize that the oncogenic glycoprotein WNT family member 4 is the link between the genetic cause of MRKH and the absence of BC women with MRKH syndrome.

Genetic Link Between Gender Dysphoria and Sex Hormone Signaling

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.

[Is Sexual Identity Optional? A Study of The Genetics of Transsexuality]

Transsexualism in the ICD-10 (International Classification of Diseases, Tenth Revision), Gender Dysphoria in adolescents and adults in the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition), is characterized by a marked incongruence between one's experienced gender and biological sex. The etiology is complex, but some hypotheses suggest that Gender Dysphoria (GD) arises from discrepant cerebral and biological sexual differentiation. Increasing evidence supports the idea of genetic vulnerability. Henningsson et al, (2004) found significant differences when they examined estrogen receptor β (ERβ) in a male-to- female (MtF) population. They suggested that a long ERβ polymorphism is more common in MtFs. Hare et al, (2009) also examined an MtF population and found a significant association between the androgen receptor (AR) and GD. Our group analyzed the same polymorphisms and found an association between ERα, ERβ and AR in GD. Our results suggest a genetic basis of GD in MtF and FtM populations. Our data corroborate the implication of the two estrogen receptors, ERα and β, and the androgen receptor in the genetic basis of GD, and advise the importance of estrogens and androgens in cerebral masculinization. Our data also confirm that sexual identity is not optional, but is determined prenatally by the genes, although it has a very important hormonal component. Therefore, its substrate is cerebral, not ideological.

Hormone and genetic study in male to female transsexual patients

BACKGROUND

Data of the literature demonstrated controversial results of a correlation between transsexualism and genetic mutations.

AIM

To evaluate the hormone and gene profile of male-female (M-F) transsexual.

SUBJECTS AND METHODS

Thirty M-F transsexuals aged 24-39. Seventeen had already undergone sex reassignment surgery, 13 were awaiting. All subjects had been undergoing estrogen and antiandrogen therapy. We studied hormones of the hypothalamus- pituitary-testicular axis, thyroid and adrenal profile, GH basal and after GHRH stimulation, IGF-I. The gene study analyzed SRY, AR, DAX1, SOX9, AZF region of the Y chromosome.

RESULTS

Pre-surgery subjects had elevated PRL, reduced testosterone and gonadotropins. Post-surgery subjects showed reduced androgens, a marked increase in LH and FSH and normal PRL. Cortisol and ACTH were similar to reference values in pre- and post-surgery patients. There was a marked increase in the baseline and post-stimulation GH values in 6 of the 13 pre-surgery patients, peaking at T15. IGF-I was similar to reference values in both groups except for one post-surgery patient, whose level was below the normal range. There were no polymorphisms in the amplified gene region for SOX9, and a single nucleotide synonimous polymorphism for DAX1. No statistically significant differences were seen in the mean of CAG repeats between controls and transsexual subjects. SRY gene was present in all subjects. Qualitative analysis of the AZFa, AZFb, and AZFc regions did not reveal any microdeletions in any subject.

CONCLUSIONS

This gender disorder does not seem to be associated with any molecular mutations of some of the main genes involved in sexual differentiation.

Gene- and environment-dependent neuroendocrine etiogenesis of homosexuality and transsexualism

Sexual brain organization is dependent on sex hormone and neurotransmitter levels occurring during critical developmental periods. The higher the androgen levels during brain organization, caused by genetic and/or environmental factors, the higher is the biological predisposition to bi- and homosexuality or even transsexualism in females and the lower it is in males. Adrenal androgen excess, leading to heterotypical sexual orientation and/or gender role behavior in genetic females, can be caused by 21-hydroxylase deficiency, especially when associated with prenatal stress. The cortisol (F) precursor 21-deoxycortisol (21-DOF) was found to be significantly increased after ACTH stimulation in homosexual as compared to heterosexual females. 21-DOF was increased significantly before and even highly significantly after ACTH stimulation in female-to-male transsexuals. In view of these data, heterozygous and homozygous forms, respectively, of 21-hydroxylase deficiency represent a genetic predisposition to androgen-dependent development of homosexuality and transsexualism in females. Testicular androgen deficiency in prenatal life, giving rise to heterotypical sexual orientation and/or gender role behavior in genetic males, may be induced by prenatal stress and/or maternal or fetal genetic alterations. Most recently, in mothers of homosexual men--following ACTH stimulation--a significantly increased prevalence of high 21-DOF plasma values and 21-DOF/F ratios was found, which surpassed the mean + 1 SD level of heterosexual control women. In homosexual men as well--following ACTH stimulation--most of the 21-DOF plasma values and 21-DOF/F ratios also surpassed the mean + 1 SD level of heterosexual men. In only one out of 9 homosexual males, neither in his blood nor in that of his mother increased 21-DOF values and 21-DOF/F ratios were found after ACTH stimulation. In this homosexual man, however, the plasma dehydroepiandrosterone sulfate (DHEA-S) values and the DHEA-S/1000 x A (A = androstenedione) ratio were increased before and after ACTH stimulation. Furthermore, highly significantly increased basal plasma levels of dehydroepiandrosterone sulfate were found in male-to-female transsexuals as compared to normal males, suggesting partial 3 beta-ol hydroxysteroid dehydrogenase deficiency to be a predisposing factor for the development of male-to-female transsexualism.

Androgen receptor repeat length polymorphism associated with male-to-female transsexualism

BACKGROUND

There is a likely genetic component to transsexualism, and genes involved in sex steroidogenesis are good candidates. We explored the specific hypothesis that male-to-female transsexualism is associated with gene variants responsible for undermasculinization and/or feminization. Specifically, we assessed the role of disease-associated repeat length polymorphisms in the androgen receptor (AR), estrogen receptor beta (ERbeta), and aromatase (CYP19) genes.

METHODS

Subject-control analysis included 112 male-to-female transsexuals and 258 non-transsexual males. Associations and interactions were investigated between CAG repeat length in the AR gene, CA repeat length in the ERbeta gene, and TTTA repeat length in the CYP19 gene and male-to-female transsexualism.

RESULTS

A significant association was identified between transsexualism and the AR allele, with transsexuals having longer AR repeat lengths than non-transsexual male control subjects (p=.04). No associations for transsexualism were evident in repeat lengths for CYP19 or ERbeta genes. Individuals were then classified as short or long for each gene polymorphism on the basis of control median polymorphism lengths in order to further elucidate possible combined effects. No interaction associations between the three genes and transsexualism were identified.

CONCLUSIONS

This study provides evidence that male gender identity might be partly mediated through the androgen receptor.

[Transsexualism as a clinical symptom of true hermaphroditism]

Transsexualism is incorrectly thought to be a disease of sexual centers (zones) of the brain but these sexual centers in the brain operate only in response to action of sexual hormones (androgens or estrogens) which are produced in the gonads and delivered to the brain by blood. In hermaphroditism the brain receives both androgens and estrogens. Transsexualism syndrome develops in cases when all sexual organs develop under the influence of one sex while sexual psychoorientation, sexual autoidentification and sexual behavior form under the influence of hormones of the other sex. Therefore, treatment of this syndrome should not consist of surgical correction of the sex according to psychic behavior of the patient but should be directed to detection of the gonad (or gonadal tissue) causing abnormal behavior and its removal. Gonad corresponding to sexual organs of the patient should be preserved. Of 19 patients with true hermaphroditism and 199 patients with false hermaphroditism observed by the authors 4 patients with true hermaphroditism had transsexualism.

A polymorphism of the CYP17 gene related to sex steroid metabolism is associated with female-to-male but not male-to-female transsexualism

OBJECTIVE

To assess the association between transsexualism and allele and genotype frequencies of the common cytochrome P450 (CYP) 17 -34 T>C single nucleotide polymorphism (SNP).

DESIGN

Case-control study.

SETTING

Academic research institution.

PATIENT(S)

102 male-to-female (MtF) and 49 female-to-male (FtM) transsexuals, 756 male controls, and 915 female controls.

INTERVENTION(S)

Buccal swabs and multiplex polymerase chain reaction on a microarray system.

MAIN OUTCOME MEASURE(S)

Analysis of the CYP17 -34 T>C SNP.

RESULT(S)

CYP17 -34 T>C SNP allele frequencies were statistically significantly different between FtM transsexuals and female controls (CYP17 T: 55/98 [56%] and CYP17 C: 43/98 [44%] versus CYP17 T: 1253/1826 [69%] and CYP17 C: 573/1826 [31%], respectively). In accordance, genotype distributions were also different between FtM transsexuals and female controls using a recessive genotype model (CYP17 T/T+T/C: 39/49 [80%] and C/C 10/49 [20%] vs. CYP17 T/T+T/C: 821/913 [90%] and C/C 92/913 [10%], respectively). The CYP17 -34 T>C allele and genotype distributions were not statistically significantly different between MtF transsexuals and male controls. Of note, the CYP17 -34 T>C allele distribution was gender-specific among controls (CYP17 C: males; 604 of 1512 [40%] vs. females; 573 of 1826 [31%]). The MtF transsexuals had an allele distribution equivalent to male controls, whereas FtM transsexuals did not follow the gender-specific allele distribution of female controls but rather had an allele distribution equivalent to MtF transsexuals and male controls.

CONCLUSION(S)

These data support CYP17 as a candidate gene of FtM transsexualism and indicate that loss of a female-specific CYP17 T -34C allele distribution pattern is associated with FtM transsexualism.

Sexual differentiation of the brain and behavior

During the intrauterine period the human brain develops in the male direction via direct action of a boy's testosterone, and in the female direction through the absence of this hormone in a girl. During this time, gender identity (the feeling of being a man or a woman), sexual orientation, and other behaviors are programmed. As sexual differentiation of the genitals takes places in the first 2 months of pregnancy, and sexual differentiation of the brain starts during the second half of pregnancy, these two processes may be influenced independently of each other, resulting in transsexuality. This also means that in the case of an ambiguous gender at birth, the degree of masculinization of the genitals may not reflect the same degree of masculinization of the brain. Differences in brain structures and brain functions have been found that are related to sexual orientation and gender.

What do the X and Y chromosomes tell us about sex and gender in forensic case analysis?

Sex determination can be particularly crucial in forensic casework such as rape cases or cases of missing persons. Biological traces have to be genetically typed and the classification of the sex is of great importance for further investigations. Lately, several papers were published on reliability of sex determination by genetic typing of amelogenin gene-specific fragments. Problems may arise not only from false detection (or non-detection) of amelogenin-specific fragments, but also in cases of chimerism (bone marrow transplants) or micro chimerism (pregnant women carrying male fetuses), and from the possible discrepancies between the biological gender and the (forensic relevant) legal gender in the personal identity documents. The phenotype based classification of the legal gender may contradict the genetic sex under several conditions as there are genetic diversity, intersex conditions and transsexualism. The forensic relevance of the possible misinterpretation (sex is not necessarily legal gender) should not be underestimated.

Endocrine Treatment of Male-to-Female Transsexuals Using Gonadotropin-Releasing Hormone Agonist

In transsexual people, cross-sex hormone therapy is an important component of medical treatment. In male-to-female transsexuals, feminizing effects should be achieved before irreversible sex reassignment surgery (SRS) is considered. The most common treatment regimen in male-to-female transsexuals is a combination of ethinyl oestradiol and cyproterone acetate, with the exception of transdermal oestradiol-17beta in individuals over the age of 40. The mortality and morbidity rates with this treatment regimen have been reported in more than 800 patients. Typical side effects include venous thrombosis, elevated liver enzymes, symptomatic gallstones, hyperprolactinaemia and depression. Sixty male-to-female transsexuals were treated with monthly injections of gonadotropin-releasing hormone agonist (GnRHa) and oral oestradiol-17beta valerate for 2 years to achieve feminisation until SRS. There was a significant decline in gonadotropins, total testosterone and calculated free testosterone. In general, the treatment regimen was well accepted. An equal increase in breast size was achieved compared to common hormone therapy. Two side effects were documented. One, venous thrombosis, occurred in a patient with a homozygous MTHFR mutation. One patient was found to be suffering from symptomatic preexisting gallstones. No other complications were documented. Liver enzymes, lipids, and prolactin levels were unchanged. Significantly increased oestradiol and SHBG serum levels were detectable. In addition, an increase in bone mass density, in the femoral neck and lumbar spine, was recorded. We conclude that cross-sex hormone treatment of male-to-female transsexuals using GnRHa and oestradiol-17beta valerate is effective, and side effects and complication rates can be reduced using the treatment regimen presented here.

Sex steroid-related genes and male-to-female transsexualism

Transsexualism is characterised by lifelong discomfort with the assigned sex and a strong identification with the opposite sex. The cause of transsexualism is unknown, but it has been suggested that an aberration in the early sexual differentiation of various brain structures may be involved. Animal experiments have revealed that the sexual differentiation of the brain is mainly due to an influence of testosterone, acting both via androgen receptors (ARs) and--after aromatase-catalyzed conversion to estradiol--via estrogen receptors (ERs). The present study examined the possible importance of three polymorphisms and their pairwise interactions for the development of male-to-female transsexualism: a CAG repeat sequence in the first exon of the AR gene, a tetra nucleotide repeat polymorphism in intron 4 of the aromatase gene, and a CA repeat polymorphism in intron 5 of the ERbeta gene. Subjects were 29 Caucasian male-to-female transsexuals and 229 healthy male controls. Transsexuals differed from controls with respect to the mean length of the ERbeta repeat polymorphism, but not with respect to the length of the other two studied polymorphisms. However, binary logistic regression analysis revealed significant partial effects for all three polymorphisms, as well as for the interaction between the AR and aromatase gene polymorphisms, on the risk of developing transsexualism. Given the small number of transsexuals in the study, the results should be interpreted with the utmost caution. Further study of the putative role of these and other sex steroid-related genes for the development of transsexualism may, however, be worthwhile.

Bone mass, bone turnover, vitamin D, and estrogen receptor gene polymorphisms in male to female transsexuals: effects of estrogenic treatment on bone metabolism of the male

The effect of chronic administration of estrogens on bone and mineral metabolism in men is not known. We have studied the effect of chronic administration of estrogens on bone mineral metabolism in a group of transsexual (TS) Canarian men, who were taking estrogens for a minimum of 3 years. This is a cross-sectional study of cases and controls and we studied biochemical markers of bone remodeling, bone mineral density (BMD), and selected biochemical and hormonal features. TS subjects had shorter stature than controls, and after adjusting for height and weight, we found that they had lower values for serum-free testosterone and higher values for BMD, both in the lumbar spine and in femoral neck. Biochemistry, bone remodeling markers, and calcitropic hormone values were similar in both groups. Finally, the distributions of vitamin D receptor (BsmI) and estrogen receptor (ER-Pvu and ER-Xba) polymorphisms were also similar in both groups. We conclude that the chronic administration of estrogens in men may produce an increase in serum estradiol, a decrease in free testosterone levels, and an increase in BMD-both in lumbar spine and in femoral neck. We found no association between the transsexual phenotype and the distribution of vitamin D receptor (BsmI) and estrogen receptor (ER-Pvu and ER-Xba).

Female-to-male transsexual with 47,XXX karyotype

BACKGROUND

There are few reports describing chromosomal abnormalities in transsexuals. In rare cases, transsexualism and sexual chromosomal multiplicity coexist. Six cases of male-to-female transsexuals with 47,XYY chromosomal pattern have been previously reported. We have not encountered any female transsexual cases with 47,XXX karyotype in the literature.

METHODS

A 21-year-old female patient came to our outpatient department with depressive symptoms and suicidal thoughts. On psychiatric interview, she reported that she had feelings of discomfort with her gender identity and had desired to be male since her childhood. Then, we performed cytogenetic investigation using blood culture and G chromosome banding.

RESULTS

Histology and DNA histograms of the patient revealed a chromosomal pattern of 47,XXX.

CONCLUSIONS

We conclude that sexual chromosomal abnormalities in some transsexuals may cause a vulnerability to development of a gender identity disorder.

Transsexualism in female monozygotic twins: a case report

OBJECTIVE

A case report is presented of a gender identity disorder involving a pair of female monozygotic twins who requested sex reassignment. As far as we know, this case is the first in psychiatric literature and supports a genetic aetiology of this disorder.

CLINICAL PICTURE

The patients were two 18-year-old female monozygotic twins who had showed symptoms of transsexualism since early childhood. They had no other physical or psychiatric disorder except borderline mental functioning.

TREATMENT

The patients were referred for sex reassignment.

OUTCOME

They were lost to follow up after initial evaluation.

CONCLUSION

In addition to other possible (yet not confirmed) causes of transsexualism, a genetic basis for this disorder is suggested by this case.

Birth order and ratio of brothers to sisters in transsexuals

BACKGROUND

As previous studies with homosexual males have revealed a later birth order, more older brothers and more brothers than sisters, this research was extended to a large series of transsexual males and females, some of whom are homosexual.

METHODS

The male sample comprised 442 male-to-female transsexuals, subdivided by sexual partner preference: 106 homosexual, 135 heterosexual, 155 bisexual and 46 asexual. One hundred female-to-male transsexuals were also studied: 75 homosexual, 16 bisexual, seven heterosexual and five asexual. Birth order was computed by both Slater's Index and Berglin's Index.

RESULTS

Homosexual male-to-female transsexuals have a later than expected birth order and more older brothers than other subgroups of male-to-female transsexuals. Each older brother increases the odds that a male transsexual is homosexual by 40 %.

CONCLUSIONS

Hypotheses explaining the extension of prior findings to this large sample of transsexual males include a progressive maternal immunization to the male foetus either through the H-Y antigen or protein-bound testosterone or alterations in foetal androgen levels in successive pregnancies, all modifying male psychosexual development. Data on the sexual orientation of younger brothers of homosexual male transsexuals in this study are not consistent with the progressive immunization hypothesis.

The disparate maternal aunt-uncle ratio in male transsexuals: an explanation invoking genomic imprinting

A significant skewing in the sex ratio in favour of females has been reported for the families of homosexual men such that there are fewer maternal uncles than aunts. This finding is repeated for a large series of transsexual families in this study. Four hundred and seventeen male-to-female transsexuals and 96 female-to-male transsexuals were assessed. Male-to-female transsexuals have a significant excess of maternal aunts vs. uncles. No differences from the expected parity were found for female-to-male transsexuals or on the paternal side. A posited explanation for these findings invokes X inactivation and genes on the X chromosome that escape inactivation but may be imprinted. Our hypothesis incorporates the known familial traits in the families of homosexuals and transsexuals by way of retention of the grand parental epigenotype on the X chromosome. Generation one would be characterized by a failure to erase the paternal imprints on the paternal X chromosome. Daughters of this second generation would produce sons that are XpY and XmY. Since XpY expresses Xist, the X chromosome is silenced and half of the sons are lost at the earliest stages of pregnancy because of the normal requirement for paternal X expression in extra-embryonic tissues. Females survive by virtue of inheriting two X chromosomes, and therefore the possibility of X chromosome counting and choice during embryonic development. In generation three, sons inheriting the paternal X after its second passage through the female germline survive, but half would inherit the feminizing Xp imprinted genes. These genes could pre-dispose the sons to feminization and subsequent development of either homosexuality or transsexualism.

Vascular reactivity is impaired in genetic females taking high-dose androgens

OBJECTIVE

To assess the vascular effects of high-dose androgen treatment in genetic females.

BACKGROUND

Male gender is an independent risk factor for coronary artery disease, suggesting either a protective effect of estrogens and/or a deleterious effect of androgens. We have recently demonstrated that androgen deprivation is associated with enhanced vascular reactivity in adult men, however, the effects of androgen excess on vascular function in humans has not been reported previously.

METHODS

We studied vascular reactivity in two groups of genetic females: 12 female-to-male transsexuals receiving long-term high-dose androgens, and 12 healthy female control subjects, matched for age and smoking history. Using external vascular ultrasound, brachial artery diameter was measured at rest, after flow increase (leading to flow-mediated dilatation [FMD], which depends on normal endothelial function) and after sublingual nitroglycerin (NTG), an endothelium-independent dilator.

RESULTS

Testosterone levels were higher (15.2+/-8.7 vs. 1.9+/-1.3 mmol/L, p < 0.001) and high-density lipoprotein cholesterol levels were lower (1.2+/-0.2 vs. 1.6+/-0.4 mmol/L, p=0.02) in the transsexuals compared with the control subjects. In each group, nine of 12 subjects were current or ex-smokers, leading to impaired FMD in both groups (5.1+/-3.7% in the transsexuals vs. 6.9+/-4.1% in controls, p=0.28). The NTG response was significantly decreased in the transsexuals (15.9+/-4.9% vs. 22+/-5.8% in controls, p=0.01), independent of the effects of age, cholesterol or vessel size.

CONCLUSIONS

Long-term treatment with high-dose androgens is associated with impaired vascular reactivity in genetic females, consistent with a deleterious effect of androgen excess on arterial physiology.

[Psychosocial and biological aspects of transsexualism]

This study is an attempt at approximating the question of transsexualism as a psycho-biological and socio-legal problem. The authors point out the role of genetic factors in sex determination and sexual features' differentiation. Social and educational environment plays a great role in forming of a psychical sex. However, the subjective feeling of sex is most probably biologically conditioned. Recognition of the problems connected with transsexualism may contribute to an improvement in quality of life of individuals suffering from disorders of sexual identification.

A critique of the possibility of genetic inheritance of homosexual orientation

Many workers in human sexuality have tried to discover causes of sexual orientation. No one theory has proved to be satisfactory. Studies of monozygotic and dizygotic twins, some of whom have been reared separately and some together, suggest that there may be an inherited component of homosexuality. Other studies, particularly those concerned with the evolution of human sexuality, question such a possibility. A further question arises because a large part of the human population is neither exclusively homosexual nor exclusively heterosexual. This paper will examine the evidence for genetic inheritance presented by twin and family studies. It will explore ways in which a gene favoring a homosexual orientation but not reproduction could continue to exist in a population. The importance of defining terms that refer to sexual orientation will be discussed in the context of determining exactly what may be inherited. Finally, the effects of accepting genetic inheritance as the cause of sexual orientation will be discussed.

Deoxyribonucleic acid histogram of testes in primary transsexualism

The influence of oestrogen on spermatogenesis was evaluated by comparing its effect on the testes of primary male transsexuals and those who had undergone hormone therapy for prostatic carcinoma. Eight primary transsexuals were studied. They had been diagnosed on clinical and psychiatric evidence and had been on oestrogen therapy for several years since puberty. Histological sections of testicular tissue obtained at reassignment surgery from 8 phenotypic male transsexuals (aged 24-32 years) with an XY chromosome complement were studied by light microscopy. The formalin-embedded specimens were analysed by flow cytometry for deoxyribonucleic acid (DNA) histograms. Both the histology and DNA histograms revealed a pattern of maturation arrest in 12 of 16 testes in which the diploid cell compartment occupied most of the spermatogenetic element, followed by tetraploid and monoploid cells. Two testes showed impaired spermatogenesis and 2 were normal. The DNA histograms and pathology were also evaluated in 20 testes after 3 to 8 years of hormone therapy in patients with advanced prostatic carcinoma (aged 60-78 years). No maturation arrest was found in these patients. Sixteen of them had a pattern of fibrosis and atrophy and 4 had impaired spermatogenesis. It was concluded that oestrogen influenced spermatogenesis and affected the maturation of spermatogonia mostly during puberty.

A female monozygotic twin pair discordant for transsexualism. Some theoretical implications

A 13-year-old girl was referred because of sexual identity problems. There was no mental illness or neurological abnormalities. As her twin sister had no sexual identity problems, it appears that transsexualism is not transmitted by a simple genetic mechanism.

A transsexual male with 47,XYY karyotype

Transsexuals are usually found to have a normal chromosome complement. The literature to date documents four transsexuals with 47,XYY pattern. This paper reports a fertile male with major cell line of 47,XYY and a gender identity disorder.

Transsexual sisters

The first documented case of sisters with transsexualism is reported. Given the low incidence of female transsexualism this is a most unlikely event and suggests that familial factors may be of aetological importance.

Two types of cross-gender identity

A revision of the typology of male cross-gender identity was carried out by means of formalized, easily replicable methods. The results suggest (1) that there are two discrete types of cross-gender identity, one heterosexual, the other homosexual; (2) that transvestism, and closely related conditions of cross-gender identity, occur exclusively or almost exclusively in heterosexuals; (3) that of the two types of transsexualism distinguished in this study, type A is, in heterosexuals, very rare or completely nonexistent; (4) that (in the course of time) transvestites or borderline transsexuals (defined below) may develop sustained cross-gender identity, as observed by Stoller (1971); (5) that although, according to Hoenig and Kenna (1974), transsexualism by itself is not an anomalous erotic preference, it is (virtually) always either preceded by transvestism or accompanied by homosexuality or cross-gender fetishism.

[New findings on the importance of the histocompatibility Y antigen for sex differentiation and its role in the origin of developmental disorders of the reproductive organs]

In the differentiation of the male reproductive organs the histocompatibility antigen Y plays an important role, which is formed under physiological conditions under the influence of a gene of the Y-chromosome in the most cell types of male mammals and occurs in the cell membranes. The H-Y is delivered by Sertoli's cells and furthers the development of the testicles. These cells moreover deliver testosterone-binding protein and an inhibiting factor for the development of Müller's ducts. For the effectiveness of testosterone the equipment of the in their function testosterone-depending cell types with androgen-receptor protein is necessary, the formation of which is conditioned by a gene lying on the X-chromosome. For the maturation and preservation of the viability of the oocytes two functioning X-chromosomes are necessary. Several disturbances of the development of the reproductive organs as well as the trans-sexuality are demonstrated taking into consideration recent realizations.

H-Y antigen expression in different tissues from transsexuals

H-Y-antigen expression was analyzed in patients with transsexuality. Peripheral blood lymphocytes and various tissues were examined using the cytotoxicity assay of Goldberg et al. (1971). Peripheral blood lymphocytes from healthy male and female subjects were used as controls as well as tissues from non-transsexual individuals and from male and female C57B1/6J mice. In three female-to-male transsexuals the peripheral blood lymphocytes were H-Y antigen positive. In these patients also their ovaries, uterus, and mammae were found to be H-Y antigen positive. Three male-to-female transsexuals were examined. The peripheral blood lymphocytes in two of these patients were found to be H-Y antigen negative. Their testes were also H-Y antigen negative, as well as the epididymus, the corpus cavernosum penis, and the cremaster muscle which was analyzed in one of them. One male-to-female transsexual had peripheral blood lymphocytes which were H-Y antigen positive; this patient had testis and corpus cavernosum penis which were also H-Y-antigen positive.

Neurobiological approaches in human behavior genetics

An attempt should be made to base analysis of problems in human behavior genetics on existing knowledge of human biochemical genetics and neurobiology. Examples for this approach are studies showing HY antigen patterns of the opposite sex in transsexuality, slight psychological deviations in heterozygotes of recessive metabolic diseases such as phenylketonuria and lipid storage diseases, and psychological studies in healthy individuals with various genetic variants of the normal human electroencephalogram (EEG). Results of such studies will help gradually to replace emotional controversy by rational assessment of facts.

[Chromosome anomalies and their consequences for deviant behavior (author's transl)]

Chromosome anomalies are always accompanied by more or less serious behavior disorders. Yet deviant behavior in autosomal chromosome aberrations, especially the Down syndrome, on account of their severity and considerable reduction of intelligence of those affected, are far less important to the public than the gonosomal aberrations: the Klinefelter syndrome (XXY), the XYY syndrome, gonadal dysgenesis (Turner's syndrome, XO).

[Transsexualism and the H-Y antigen]

First reports about incongruous H-Y antigen status in male-to-female and female-to-male transsexuals have been published by us in 1979. Meanwhile H-Y antigen expression was analyzed with the cytotoxicity assay of Goldberg et al. in 61 transsexuals. In 55 cases H-Y antigen status was found discordant with the anatomical, chromosomal and hormonal sex and corresponded to the gender identity of transsexuals. The relative frequency was 0,91. In 33 male-to-female transsexuals 29 were H-Y negative, one was intermediate, three were H-Y positive. In 28 female-to-male transsexuals 25 were H-Y positive, one was intermediate, two were H-Y negative. The new findings of an incongruous H-Y antigen status in genuine transsexuals may lead to new considerations about the pathogenesis of the disease and about the function of H-Y antigen.

H-Y antigen in transsexuality, and how to explain testis differentiation in H-Y antigen-negative males and ovary differentiation in H-Y antigen-positive females

H-Y antigen was determined in eight transsexual patients. Two of the four male-to-female transsexual patients typed as H-Y antigen-negative, while the other two typed as expected from their phenotypic and gonadal sex, namely H-Y antigen-positive. Of the four female-to-male transsexual patients, three typed as H-Y antigen-positive and one was H-Y antigen-negative, as expected. The presence of normal testes in H-Y antigen-negative males is assumed to result from a mutation of nucleotide sequences of the H-Y structural gene for antigenic determinants. Thus, an H-Y is produced with normal receptor-binding activity which can sustain the testis determination of the bipotent gonadal anlage. In the case of H-Y antigen-positive females with normal ovaries a deletion of the autosomally located H-Y structural gene is assumed. This deletion should affect sequences for repressor-binding (as was suggested for H-Y antigen-positive XX-males) and for receptor-binding activity of the H-Y antigen molecule. The resulting H-Y antigen is unable to bind to the gonadal receptor of the bipotent gonadal anlage. Thus an ovary is determined. The relevance of H-Y antigen for the aetiology of transsexualism is discussed.