Molecular diagnosis of 5α-reductase deficiency in 4 elite young female athletes through hormonal screening for hyperandrogenism

The Biological Basis of Sex Differences in Athletic Performance: Consensus Statement for the American College of Sports Medicine

ABSTRACT

Biological sex is a primary determinant of athletic performance because of fundamental sex differences in anatomy and physiology dictated by sex chromosomes and sex hormones. Adult men are typically stronger, more powerful, and faster than women of similar age and training status. Thus, for athletic events and sports relying on endurance, muscle strength, speed, and power, males typically outperform females by 10%-30% depending on the requirements of the event. These sex differences in performance emerge with the onset of puberty and coincide with the increase in endogenous sex steroid hormones, in particular testosterone in males, which increases 30-fold by adulthood, but remains low in females. The primary goal of this consensus statement is to provide the latest scientific knowledge and mechanisms for the sex differences in athletic performance. This review highlights the differences in anatomy and physiology between males and females that are primary determinants of the sex differences in athletic performance and in response to exercise training, and the role of sex steroid hormones (particularly testosterone and estradiol). We also identify historical and nonphysiological factors that influence the sex differences in performance. Finally, we identify gaps in the knowledge of sex differences in athletic performance and the underlying mechanisms, providing substantial opportunities for high-impact studies. A major step toward closing the knowledge gap is to include more and equitable numbers of women to that of men in mechanistic studies that determine any of the sex differences in response to an acute bout of exercise, exercise training, and athletic performance.

Clinical, Hormonal, and Genetic Characteristics of 5α-Reductase Type 2 Deficiency in 103 Chinese Patients

OBJECTIVE

5α-Reductase type 2 (5α-RD2) deficiency causes variable degrees of undervirilization in patients. The correlation between its genotype and phenotype is unclear.

METHODS

We retrospectively evaluated 103 patients with 46,XY disorders of sex development who were diagnosed with 5α-RD2 deficiency.

RESULTS

The prevalence of female sex assignment (P = .008) and the incidences of cryptorchidism (P = .0003) and bifid scrotum (P = .0002) in the non-p.R227Q variant group were higher, but there were no significant differences in the incidences of hypospadias and isolated microphallus. The external masculinization score in the non-p.R227Q variant group was lower than that in the homozygous p.R227Q variant (P = .019) and compound heterozygous p.R227Q variant groups (P = .013). The level of anti-Mullerian hormone in the non-p.R227Q variant group was lower than that in the homozygous p.R227Q variant (P < .001) and compound heterozygous p.R227Q variant groups (P = .006). The testosterone-to-dihydrotestosterone ratio of the homozygous p.R227Q variant group was higher than that of the non-p.R227Q variant (P = .018) and compound heterozygous p.R227Q variant groups (P = .029). Twenty-three reportedly pathogenic variants and 11 novel steroid 5α-reductase 2 (SRD5A2) variants were identified.

CONCLUSION

Compared with patients without p.R227Q, patients with p.R227Q exhibited higher external masculinization scores and anti-Mullerian hormone expression, a lower prevalence of female sex assignment, and lower incidences of cryptorchidism and bifid scrotum. We identified 23 reportedly pathogenic SRD5A2 variants and 11 novel SRD5A2 variants that led to 5α-RD2 deficiency. We established a genotype-phenotype correlation, and patients with p.R227Q showed a relatively mild phenotype.

Comparing metabolic profiles between female endurance athletes and non-athletes reveals differences in androgen and corticosteroid levels

Endurance training is associated with physiological changes in elite athletes, but little is known about female-specific effects of endurance training. Despite the significant rise in female sports participation, findings from studies performed on male athletes are largely extrapolated to females without taking into consideration sex-specific differences in metabolism. Subsequently, this study aimed to investigate the steroid hormone profiles of elite female endurance athletes in comparison with their non-athletic counterparts. Untargeted metabolomics-based mass spectroscopy combined with ultra-high-performance liquid chromatography was performed on serum samples from 51 elite female endurance athletes and 197 non-athletic females. The results showed that, compared to non-athletic females, certain androgen, pregnenolone, and progestin steroid hormones were reduced in elite female endurance athletes, while corticosteroids were elevated. The most significantly altered steroid hormones were 5alpha-androstan-3alpha,17alpha-diol monosulfate (FDR = 1.90 × 10^-05), androstenediol (3alpha, 17alpha) monosulfate (FDR = 2.93 × 10^-04), and cortisol (FDR = 2.93 × 10^-04). Conclusively, the present study suggests that elite female endurance athletes have a unique steroid hormone profile with implications on their general health and performance.

Primary Amenorrhea Due to Anatomical Abnormalities of the Reproductive Tract: Molecular Insight

Congenital anomalies of the female reproductive tract that present with primary amenorrhea involve Müllerian aplasia, also known as Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS), and cervical and vaginal anomalies that completely obstruct the reproductive tract. Karyotype abnormalities do not exclude the diagnosis of MRKHS. Familial cases of Müllerian anomalies and associated malformations of the urinary and skeletal systems strongly suggest a complex genetic etiology, but so far, the molecular mechanism in the vast majority of cases remains unknown. Primary amenorrhea may also be the first presentation of complete androgen insensitivity syndrome, steroid 5α-reductase type 2 deficiency, 17β-hydroxysteroid dehydrogenase type 3 deficiency, and Leydig cells hypoplasia type 1; therefore, these disorders should be considered in the differential diagnosis of the congenital absence of the uterus and vagina. The molecular diagnosis in the majority of these cases can be established.

Of Athletes, Bodies, and Rules: Making Sense of Caster Semenya

This article aims to systematically deconstruct four distinct narratives derived from the case of Caster Semenya v. IAAF (Court of Arbitration for Sport).

Integrative and Analytical Review of the 5-Alpha-Reductase Type 2 Deficiency Worldwide

Introduction

The conversion of testosterone into dihydrotestosterone is catalyzed by the 5α-reductase type 2 enzyme which plays a crucial role in the external genitalia virilization. It is encoded by the SRD5A2 gene. Allelic variants in this gene cause a 46,XY DSD with no genotype-phenotype relationship. It was firstly reported in the early 70s from isolated clusters. Since then, several cases have been reported. Putting together, it will expand the knowledge on the molecular bases of androgen milieu.

Methods

We searched for SRD5A2 allelic variants (AV) in the literature (PubMed, Embase, MEDLINE) and websites (ensembl, HGMD, ClinVar). Only cases with AV in both alleles, either in homozygous or compound heterozygous were included. The included cases were analyzed according to ethnicity, exon, domain, aminoacid (aa) conservation, age at diagnosis, sex assignment, gender reassignment, external genitalia virilization and functional studies. External genitalia virilization was scored using Sinnecker scale. Conservation analysis was carried out using the CONSURF platform. For categorical variables, we used X2 test and Cramer's V. Continuous variables were analyzed by t test or ANOVA. Concordance was estimated by Kappa.

Results

We identified 434 cases of 5ARD2 deficiencies from 44 countries. Most came from Turkey (23%), China (17%), Italy (9%), and Brazil (7%). Sixty-nine percent were assigned as female. There were 70% of homozygous allelic variants and 30% compound heterozygous. Most were missense variants (76%). However, small indels (11%), splicing (5%) and large deletions (4%) were all reported. They were distributed along with all exons with exon 1 (33%) and exon 4 (25%) predominance. Allelic variants in the exon 4 (NADPH-binding domain) resulted in lower virilization (p<0.0001). The codons 55, 65, 196, 235 and 246 are hotspots making up 25% of all allelic variants. Most of them (76%) were located at conserved aa. However, allelic variants at non-conserved aa were more frequently indels (28% vs 6%; p<0.01). The overall rate of gender change from female to male ranged from 16% to 70%. The lowest rate of gender change from female to male occurred in Turkey and the highest in Brazil. External genitalia virilization was similar between those who changed and those who kept their assigned gender. The gender change rate was significantly different across the countries (V=0.44; p<0.001) even with similar virilization scores.

Conclusion

5ARD2 deficiency has a worldwide distribution. Allelic variants at the NADPH-ligand region cause lower virilization. Genitalia virilization influenced sex assignment but not gender change which was influenced by cultural aspects across the countries. Molecular diagnosis influenced on sex assignment, favoring male sex assignment in newborns with 5α-reductase type 2 deficiency.

Novel Genotype in Two Siblings with 5-α-reductase 2 Deficiency: Different Clinical Course due to the Time of Diagnosis

Steroid 5-α-reductase-2 (5-ARD) deficiency is a result of mutations of the SRD5A2 gene. It causes the disorder of sexual differentiation (DSD) in 46,XY individuals with a variable genital phenotype. We present two siblings with female external genitalia at birth and bilateral inguinal testes, raised as females. These are the first molecularly characterized patients from the Republic of North Macedonia (RN Macedonia) with a different clinical course due to the time of the diagnosis. Diagnosis of Patient 1 was based upon the detection of bilateral inguinal testes and testosterone/dihidrotestosterone ratio. Sex reversal was initiated by testes removal at the age of 20 months. Breast implantation and vaginoplasty were performed in adolescence and the girl is comfortable with the female sex. Her sibling, Patient 2, raised as a girl, was clinically assessed at 11.5 years due to the growth of phalus, deep voice and Adam's apple enlargement. No change of gender was accepted. Complex molecular analysis including multiplex quantitative fluorescent polymerase chain reaction (PCR) screening for sex chromosome aneuploidies and SRY presence, Sanger sequencing combined with multiplex ligation-dependent probe amplification (MLPA), microarray-based comparative genomic hybridization (aCGH), and real-time PCR analysis for detection of exon copy number changes confirmed a novel c.146C>A (p.Ala49Asp) point mutation in the first exon inherited from the mother, and complete deletion of the first exon and adjacent regions inherited from the father. Novel genotype causing 5-ARD is presented. Genetic analysis is useful for the diagnosis and timely gender assignment in patients with 5-ARD. However, final gender assignment is difficult and requires combined medical interventions.

The Interconnected Histories of Endocrinology and Eligibility in Women's Sport

This report illustrates the links between history, sport, endocrinology, and genetics to show the ways in which historical context is key to understanding the current conversations and controversies about who may compete in the female category in elite sport. The International Association of Athletics Federations (IAAF) introduced hyperandrogenemia regulations for women's competitions in 2011, followed by the International Olympic Committee (IOC) for the 2012 Olympics. The policies concern female athletes who naturally produce higher-than-average levels of testosterone and want to compete in the women's category. Hyperandrogenemia guidelines are the current effort in a long series of attempts to determine women's eligibility scientifically. Scientific endeavors to control who may participate as a woman illustrate the impossibility of neatly classifying competitors by sex and discriminate against women with differences of sex development (also called intersex by some).

Large divergence in testosterone concentrations between men and women: Frame of reference for elite athletes in sex-specific competition in sports, a narrative review

OBJECTIVE

The purpose of this narrative review was to summarize available data on testosterone levels in normal, healthy adult males and females, to provide a physiologic reference framework to evaluate testosterone levels reported in males and females with conditions that elevate androgens, such as disorders of sex development (DSD), and to determine the separation or overlap of testosterone levels between normal and affected males and females.

METHODS

A literature review was conducted for published papers, from peer reviewed journals, reporting testosterone levels in healthy males and females, males with 46XY DSD, and females with hyperandrogenism due to polycystic ovary syndrome (PCOS). Papers were selected that had adequate characterization of participants, and description of the methodology for measurement of serum testosterone and reporting of results.

RESULTS

In the healthy, normal males and females, there was a clear bimodal distribution of testosterone levels, with the lower end of the male range being four- to fivefold higher than the upper end of the female range(males 8.8-30.9 nmol/L, females 0.4-2.0 nmol/L). Individuals with 46XY DSD, specifically those with 5-alpha reductase deficiency, type 2 and androgen insensitivity syndrome testosterone levels that were within normal male range. Females with PCOS or congenital adrenal hyperplasia were above the normal female range but still below the normal male range.

CONCLUSIONS

Existing studies strongly support a bimodal distribution of serum testosterone levels in females compared to males. These data should be considered in the discussion of female competition eligibility in individuals with possible DSD or hyperandrogenism.

Pediatric endocrinology: an overview of the last decade

Over the past decade, considerable progress has been made in the field of pediatric endocrinology. However, there is still a long way to go regarding the exploration of novel avenues, such as epigenetics, the changing views on the pathophysiology and derived therapy of specific disorders, and the prevention of prevalent diseases. The next decade will hopefully bring the consolidation of most of those achievements and the development of new pathways for further progress.

Impossible "Choices": The Inherent Harms of Regulating Women's Testosterone in Sport

In April 2018, the International Association of Athletics Federations (IAAF) released new regulations placing a ceiling on women athletes' natural testosterone levels to "ensure fair and meaningful competition." The regulations revise previous ones with the same intent. They require women with higher natural levels of testosterone and androgen sensitivity who compete in a set of "restricted" events to lower their testosterone levels to below a designated threshold. If they do not lower their testosterone, women may compete in the male category, in an intersex category, at the national level, or in unrestricted events. Women may also challenge the regulation, whether or not they have lowered their testosterone, or quit sport. Irrespective of IAAF's stated aims, the options forced by the new regulations are impossible choices. They violate dignity, threaten privacy, and mete out both suspicion and judgement on the sex and gender identity of the athletes regulated.

Do anabolic-androgenic steroids have performance-enhancing effects in female athletes?

Doping with anabolic-androgenic steroids (AAS) is common among both male and female athletes and is a growing public health problem. Review of historical data of systematic state-sponsored doping programs implemented by the German Democratic Republic in elite female athletes and from clinical trials of testosterone administration in non-athlete women suggests that AAS have ergogenic effects in women. The use of AAS in female athletes has been associated with adverse effects that include acne, hirsutism, deepening of the voice and menstrual disturbances; life-threatening adverse effects such as cardiac arrhythmias and sudden death have also been reported. Therefore, detection of AAS abuse in female athletes is important to ensure fairness in competition; at the same time, the athletes should be educated regarding the adverse consequences of AAS use. Although administration of exogenous androgens have been associated with ergogenic effects, it remains unclear whether endogenous hyperandrogenism seen in some medical conditions such as disorders of sexual development (DSD), congenital adrenal hyperplasia and polycystic ovary syndrome, confers any competitive advantage. Well-designed studies are needed to determine the effects of endogenous hyperandrogenism on athletic performance in female athletes.

Effects of short-term DHEA intake on hormonal responses in young recreationally trained athletes: modulation by gender

BACKGROUND

Dehydroepiandrosterone (DHEA) figures on the World Anti-Doping Agency list of prohibited substances in sport because it is assumed that athletes expect a significant increase in testosterone through DHEA administration. The literature on the hormonal effects of DHEA intake nevertheless appears to be very scant in healthy young subjects, especially women.

PURPOSE

We examined the effects of DHEA on adrenal and gonadal hormones, IGF1 and free T3 in healthy young male and female recreationally trained volunteers.

METHODS

The study followed a double-blind, randomized-order crossover design. Lean healthy young men (n = 10) and women (n = 11), with all women using oral contraceptives, were treated daily with 100 mg of DHEA and placebo for 4 weeks. DHEA, DHEA-sulfate (DHEA-S), androstenedione, total testosterone (Tes), dihydrotestosterone (DHT), SHBG, estrone, cortisol, IGF1, and free T3 were measured before, in the middle and at the end of each treatment, as were blood glucose, liver transaminases and lipid status.

RESULTS

We observed a significant increase in DHEA, DHEA-S, androstenedione, Tes, DHT, and estrone in both men and women in the middle and at the end of DHEA treatment, but the increase in Tes was more marked in women (p < 0.001) than men (p < 0.05). No changes were found in the other parameters, irrespective of gender.

CONCLUSION

In young athletes, DHEA administration induces significant blood hormonal changes, some modulated by gender, which can be used as biomarkers of doping.

Sex reversal induces size and performance differences among females of the African pygmy mouse, Mus minutoides

Differences in biological performance, at both intra- and inter-specific levels, have often been linked to morphology but seldom to behavioural or genotypic effects. We tested performance at the intraspecific level by measuring bite force in the African pygmy mouse, Mus minutoides. This species displays an unusual sex determination system, with sex-reversed, X*Y females carrying a feminizing X* chromosome. X*Y females cannot be differentiated from XX females based on external or gonadal morphology; however, they are known to be more aggressive. We found that bite force was higher in X*Y females than in other females and males. We then performed geometric morphometric analyses on their skulls and mandibles and found that the higher performance of X*Y females was mainly explained by a greater overall skull size. The effects of the X* chromosome thus go beyond feminization, and extend to whole-organism performance and morphology. Our results also suggest limited effects of behaviour on bite force.

The 2015 Pediatric Endocrine Society Ethics Symposium: Controversies Regarding 'Gender Verification' of Elite Female Athletes - Sex Testing to Hyperandrogenism

An overview of the Pediatric Endocrine Society's Ethics Symposium held in April 2015 at the annual meeting of the Pediatric Academic Societies is provided by the panel moderators with a summary of efforts by international athletic governing bodies over several decades to 'verify' the eligibility of athletes to compete in female only events, culminating in the hyperandrogenism policies that were the focus of the panel debate. This history was extensively reviewed in the symposium's opening presentation by Alan Rogol, in collaboration with Lindsay Pieper. Two sharply divergent views were then conveyed. David Allen's, in support, is provided in his article which follows. The opposing case, provided by Katrina Karkazis, is extensively summarized herein and reflected in her Science essay with Rebecca Jordan-Young which appeared shortly after the meeting. The subsequent ruling by the international Court of Arbitration for Sport to suspend the hyperandrogenism rule is noted with some speculation regarding the implications if it is upheld.

Genes, Gender, Hormones, and Doping in Sport: A Convoluted Tale

We are writing this piece in the aftermath of the 2016 Olympic Games in Rio de Janeiro, Brazil. Each of the words in the title plays a role(s) in deciding who may compete, especially who may compete as a woman. We shall be careful to disentangle the issues of genes and gender from hormonal levels of the potent androgen testosterone, and very clearly demarcate these natural occurrences from those of doping, for which the World Anti-Doping Agency has established strict guidelines. These elements became conflated in the aftermath of the Court of Arbitration of Sport's decision, now more than 2 years ago, concerning the teenage Indian sprinter, Dutee Chand. Although many people associate hyperandrogenism with doping and gender determination, each is different and has a distinct function.

Determination and regulation of body composition in elite athletes

In 2011, the International Association of Athletics Federations (IAAF) and IOC introduced a ‘hyperandrogenism’ rule that excluded women with a serum testosterone >10 nmol/L from participating in elite sport. This rule was based on the false premise that the greater lean body mass in men was a consequence of their higher serum testosterone. This rule did not have scientific backing and the Court of Arbitration for Sport subsequently rescinded the rule following an appeal from an Indian athlete barred from the Commonwealth Games. This review covers the scientific knowledge about the development and regulation of body composition in humans but also considers the lessons learnt from evolution and breeding in animals. The importance of heredity has been documented in family and twin studies. The roles of growth hormone and sex steroids are reviewed. The Androgen Insensitivity Syndrome (AIS) is considered as a model of the role of testosterone in development of body composition and also as evidence of the importance of other factors carried on the Y-chromosome that are of prime importance but have been systematically ignored. Finally the key factors determining body composition are considered and placed in a suggested order of importance.

What do we do about women athletes with testes?

Elite sport and the measures imposed to prevent 'men' from 'cheating' by posing as women in women's events cast interesting light on notions of sex and gender. Some women have testes, organs that produce testosterone, because they are trans women or they have an intersex state. Testosterone is recognised as a performance-enhancing substance in at least some circumstances, and therefore, women with testes may possess an advantage when competing in some sport against women without testes, though this has never been subjected to rigorous scientific testing. The International Olympic Committee and the International Association of Athletics Federation have decreed that such individuals can compete only if they undergo medical and surgical treatment, which is likely to mean gonadectomy. This might be considered to impose an unethical demand on the individual concerned and constitute an infringement of bodily autonomy for that individual. It also suggests a binary view of sex/gender that is simplistic and not scientifically accurate. I discuss this approach and consider alternative methods of approaching the problem of women with testes in athletics.

Ethics of Regulating Competition for Women with Hyperandrogenism

The International Association for Athletics Federations (IAAF) has been granted 2 years to submit further evidence showing a correlation between higher levels of testosterone and a competitive advantage. This article first presents the case of Caster Semenya, which triggered the drafting by IAAF of the regulations on eligibility of female athletes to compete in the female category in 2011. Then the IAAF regulations are critically analyzed from a scientific and ethical point of view. Finally, the Court of Arbitration for Sport decision to suspend the regulations pending further evidence provided by IAAF, and what this means for the future of sports, is discussed.

Natural selection for genetic variants in sport: the role of Y chromosome genes in elite female athletes with 46,XY DSD

At present, it is widely assumed that hyperandrogenism in female athletes confers an unfair competitive advantage. This view is perpetuated in current regulations governing eligibility of female athletes with hyperandrogenism to compete, which identify testosterone levels in the male range as the critical factor. Detailed evidence is presented here for the first time that genes for stature (and possibly other genes) on the Y chromosome are responsible for the increased frequency of 46,XY disorder of sex development (46,XY DSD) among elite female athletes identified by eligibility tests. In many cases, androgens are non-functional or, alternatively, absent and therefore testosterone cannot be responsible for their athletic success. Genetic variation has a major role in the selection of individuals for training and success in competition; however, this variation is not grounds for determining who should compete in athletic events. There is no convincing evidence to support the view that hyperandrogenism is associated with performance advantage in female athletes. Current time-consuming regulations may lead to the unwelcome resurgence of innuendo in the media and coercion of female athletes into accepting gonadectomy and other treatments to which they might otherwise not have been subjected. These regulations should be withdrawn on the grounds that they are not supported scientifically, are discriminatory towards women and place some female athletes at risk of unnecessary and potentially harmful investigations. Improved understanding about genetic factors that lead to selection in sport should offer reassurance that women with hyperandrogenism possess no physical attribute relevant to athletic performance that is neither attainable, nor present in other women.

Serum androgen levels in elite female athletes

OBJECTIVE

Prior to the implementation of the blood steroidal module of the Athlete Biological Passport, we measured the serum androgen levels among a large population of high-level female athletes as well as the prevalence of biochemical hyperandrogenism and some disorders of sex development (DSD).

METHODS AND RESULTS

In 849 elite female athletes, serum T, dehydroepiandrosterone sulphate, androstenedione, SHBG, and gonadotrophins were measured by liquid chromatography-mass spectrometry high resolution or immunoassay. Free T was calculated. The sampling hour, age, and type of athletic event only had a small influence on T concentration, whereas ethnicity had not. Among the 85.5% that did not use oral contraceptives, 168 of 717 athletes were oligo- or amenorrhoic. The oral contraceptive users showed the lowest serum androgen and gonadotrophin and the highest SHBG concentrations. After having removed five doped athletes and five DSD women from our population, median T and free T values were close to those reported in sedentary young women. The 99th percentile for T concentration was calculated at 3.08 nmol/L, which is below the 10 nmol/L threshold used for competition eligibility of hyperandrogenic women with normal androgen sensitivity. Prevalence of hyperandrogenic 46 XY DSD in our athletic population is approximately 7 per 1000, which is 140 times higher than expected in the general population.

CONCLUSION

This is the first study to establish normative serum androgens values in elite female athletes, while taking into account the possible influence of menstrual status, oral contraceptive use, type of athletic event, and ethnicity. These findings should help to develop the blood steroidal module of the Athlete Biological Passport and to refine more evidence-based fair policies and recommendations concerning hyperandrogenism in female athletes.

Hurdling over sex? Sport, science, and equity

Between 1968 and 1999, the International Olympic Committee (IOC) required all female athletes to undergo genetic testing as part of its sex verification policy, under the assumption that it needed to prevent men from impersonating women and competing in female-only events. After critics convinced officials that genetic testing was scientifically and ethically flawed for this purpose, the IOC replaced the policy in 1999 with a system allowing for medical evaluations of an athlete's sex only in cases of "reasonable suspicion," but this system also created injustice for athletes and stoked international controversies. In 2011, the IOC adopted a new policy on female hyperandrogenism, which established an upper hormonal limit for athletes eligible to compete in women's sporting events. This new policy, however, still leaves important medical and ethical issues unaddressed. We review the history of sex verification policies and make specific recommendations on ways to improve justice for athletes within the bounds of the current hyperandrogenism policy, including suggestions to clarify the purpose of the policy, to ensure privacy and confidentiality, to gain informed consent, to promote psychological health, and to deploy equitable administration and eligibility standards for male and female athletes.