XY Disorders/differences Of Sex Development Research Articles

OR27-01 Combining Clinical and Genetic Approaches in Diagnosing a Large Brazilian Cohort of Patients with 46,XY Differences/Disorders of Sex Development (DSD)

Background: It is recommended a multidisciplinary approach consisted of clinical, hormonal and genetic workups for diagnosing 46,XY DSD. However, no previous study has quantified how useful is this combined approach. Objectives: To retrospectively review the clinical and genetic findings for diagnosing a large cohort of patients with 46,XY DSD from a single Brazilian center. Methods: 247 non-syndromic 46,XY DSD individuals (159 sporadic and 88 familial cases from 39 families) were studied. Clinical and hormonal data were collected from medical files. Testosterone (T), androstenedione (A) were measured by immunoradiometric or immunofluorimetric assays and dihydrotestosterone (DHT) by RIA after celite chromatography or by liquid chromatography tandem mass spectrometry; T/DHT and T/A ratios were calculated. Analysis of sensitivity (SE), specificity (SP) of T/DHT was performed, being the molecular diagnosis considered the gold standard for diagnosing SRD5A2 deficiency. A T/A>0.8 was considered indicative of 17ß-HSDB3 deficiency. The patients were clinically classified into four subgroups: 1) androgen insensitivity syndrome (AIS), 2) gonadal dysgenesis (GD); 3) defects in androgen synthesis (DAS) and 4) DSD of unknown etiology. Molecular studies were performed by Sanger sequencing and/ or massively parallel sequencing (MPS). Results: The median age at first visit was 14 years (range 0.1 to 59 years). The molecular diagnosis was established in 96.5% of the cases with AIS (n=28/29), in 96% of the subjects with DAS (n=46/48), in 36% of the patients with GD (n=21/57) and in 26.7% (n=15/56) with DSD of unknown etiology. The best cut-off for T/DHT in basal state and hCG stimulated was 12.5 (SE=100%; SP=78.57%) and 24 (SE=87.5%; SP=95.7%) respectively. A T/A<0.8 was observed in 13/16 (81%) of the patients with molecular diagnosis of 17ß-HSDB3 deficiency and also in 1/49 patients with other diagnose. Classification according to the phenotype matched with the genetic diagnosis in most cases. The molecular evaluation allowed that 16% (9/56) of the patients that were classified as DSD of unknow etiology had a definitive diagnosis, including six GD cases, two individuals with SRD5A2 deficiency and one with 17ß-HSDB3 deficiency. A clear AIS phenotype of five patients allowed us to consider and prove the pathogenicity of two synonymous and one promoter region variants as the cause of AIS. The combination of clinical and molecular diagnosis led to an increase in 8% the diagnosis in a total of 116 index-cases (58.5%) with a molecular diagnosis. Conclusion: Considering the phenotype heterogeneity, pitfalls of the hormonal assessment and number of genes involved, it is reasonable to consider MPS as a first test for diagnosing patients with 46,XY DSD. However, the combination of clinical and molecular diagnosis is more accurate than either strategies alone in diagnosing 46,XY DSD.

Female hyperandrogenism and elite sport.

Emerging evidence indicates that testosterone, which can increase muscle mass and strength, stimulates erythropoiesis, promotes competitive behaviour, and enhances the physical performance of women. Indeed, the levels of testosterone within the normal female range are related to muscle mass and athletic performance in female athletes. Furthermore, among these athletes, the prevalence of hyperandrogenic conditions, including both polycystic ovary syndrome and rare differences/disorders of sex development (DSD), which may greatly increase testosterone production, are elevated. Thus, if the androgen receptors of an individual with XY DSD are functional, her muscle mass will develop like that of a man. These findings have led to the proposal that essential hyperandrogenism is beneficial for athletic performance and plays a role in the choice by women to compete in athletic activities. Moreover, a recent randomized controlled trial demonstrated a significant increase in the lean mass and aerobic performance by young exercising women when their testosterone levels were enhanced moderately. Circulating testosterone is considered the strongest factor to explain the male advantage in sport performance, ranging between 10 and 20%. It appears to be unfair to allow female athletes with endogenous testosterone levels in the male range (i.e. 10–20 times higher than normal) to compete against those with normal female androgen levels. In 2012, this consideration led international organizations to establish eligibility regulations for the female classification in order to ensure fair and meaningful competition, but the regulations are controversial and have been challenged in court.

Oligogenic Origin of Differences of Sex Development in Humans.

Sex development is a very complex biological event that requires the concerted collaboration of a large network of genes in a spatial and temporal correct fashion. In the past, much has been learned about human sex development from monogenic disorders/differences of sex development (DSD), but the broad spectrum of phenotypes in numerous DSD individuals remains a conundrum. Currently, the genetic cause of less than 50% of DSD individuals has been solved and oligogenic disease has been proposed. In recent years, multiple genetic hits have been found in individuals with DSD thanks to high throughput sequencing. Our group has been searching for additional genetic hits explaining the phenotypic variability over the past years in two cohorts of patients: 46,XY DSD patients carriers of NR5A1 variants and 46,XY DSD and 46,XX DSD with MAMLD1 variants. In both cohorts, our results suggest that the broad phenotypes may be explained by oligogenic origin, in which multiple hits may contribute to a DSD phenotype, unique to each individual. A search for an underlying network of the identified genes also revealed that a considerable number of these genes showed interactions, suggesting that genetic variations in these genes may affect sex development in concert.

Analysis of variants in GATA4 and FOG2/ZFPM2 demonstrates benign contribution to 46,XY disorders of sex development.

BackgroundGATA‐binding protein 4 (GATA4) and Friend of GATA 2 protein (FOG2, also known as ZFPM2) form a heterodimer complex that has been shown to influence transcription of genes in a number of developmental systems. Recent evidence has also shown these genes play a role in gonadal sexual differentiation in humans. Previously we identified four variants in GATA4 and an unexpectedly large number of variants in ZFPM2 in a cohort of individuals with 46,XY Differences/Disorders of Sex Development (DSD) (Eggers et al, Genome Biology, 2016; 17: 243).MethodHere, we review variant curation and test the functional activity of GATA4 and ZFPM2 variants. We assess variant transcriptional activity on gonadal specific promoters (Sox9 and AMH) and variant protein–protein interactions.ResultsOur findings support that the majority of GATA4 and ZFPM2 variants we identified are benign in their contribution to 46,XY DSD. Indeed, only one variant, in the conserved N‐terminal zinc finger of GATA4, was considered pathogenic, with functional analysis confirming differences in its ability to regulate Sox9 and AMH and in protein interaction with ZFPM2.ConclusionsOur study helps define the genetic factors contributing to 46,XY DSD and suggests that the majority of variants we identified in GATA4 and ZFPM2/FOG2 are not causative.

The gene encoding the ketogenic enzyme HMGCS2 displays a unique expression during gonad development in mice.

Disorders/differences of sex development (DSD) cause profound psychological and reproductive consequences for the affected individuals, however, most are still unexplained at the molecular level. Here, we present a novel gene, 3-hydroxy-3-methylglutaryl coenzyme A synthase 2 (HMGCS2), encoding a metabolic enzyme in the liver important for energy production from fatty acids, that shows an unusual expression pattern in developing fetal mouse gonads. Shortly after gonadal sex determination it is up-regulated in the developing testes following a very similar spatial and temporal pattern as the male-determining gene Sry in Sertoli cells before switching to ovarian enriched expression. To test if Hmgcs2 is important for gonad development in mammals, we pursued two lines of investigations. Firstly, we generated Hmgcs2-null mice using CRISPR/Cas9 and found that these mice had gonads that developed normally even on a sensitized background. Secondly, we screened 46,XY DSD patients with gonadal dysgenesis and identified two unrelated patients with a deletion and a deleterious missense variant in HMGCS2 respectively. However, both variants were heterozygous, suggesting that HMGCS2 might not be the causative gene. Analysis of a larger number of patients in the future might shed more light into the possible association of HMGCS2 with human gonadal development.

Pathogenic variants in the DEAH-box RNA helicase DHX37 are a frequent cause of 46,XY gonadal dysgenesis and 46,XY testicular regression syndrome

PurposeXY individuals with disorders/differences of sex development (DSD) are characterized by reduced androgenization caused, in some children, by gonadal dysgenesis or testis regression during fetal development. The genetic etiology for most patients with 46,XY gonadal dysgenesis and for all patients with testicular regression syndrome (TRS) is unknown. MethodsWe performed exome and/or Sanger sequencing in 145 individuals with 46,XY DSD of unknown etiology including gonadal dysgenesis and TRS. ResultsThirteen children carried heterozygous missense pathogenic variants involving the RNA helicase DHX37, which is essential for ribosome biogenesis. Enrichment of rare/novel DHX37 missense variants in 46,XY DSD is highly significant compared with controls (P value = 5.8 × 10−10). Five variants are de novo (P value = 1.5 × 10−5). Twelve variants are clustered in two highly conserved functional domains and were specifically associated with gonadal dysgenesis and TRS. Consistent with a role in early testis development, DHX37 is expressed specifically in somatic cells of the developing human and mouse testis. ConclusionDHX37 pathogenic variants are a new cause of an autosomal dominant form of 46,XY DSD, including gonadal dysgenesis and TRS, showing that these conditions are part of a clinical spectrum. This raises the possibility that some forms of DSD may be a ribosomopathy.

Assembling the jigsaw puzzle: CBX2 isoform 2 and its targets in disorders/differences of sex development

Background One of the defining moments of human life occurs early during embryonic development, when individuals sexually differentiate into either male or female. Perturbation of this process can lead to disorders/differences of sex development (DSD). Chromobox protein homolog 2 (CBX2) has two distinct isoforms, CBX2.1 and CBX2.2: the role of CBX2.1 in DSD has been previously established, yet to date the function of the smaller isoform CBX2.2 remains unknown. Methods The genomic DNA of two 46,XY DSD patients was analysed using whole exome sequencing. Furthermore, protein/DNA interaction studies were performed using DNA adenine methyltransferase identification (DamID) to identify putative binding partners of CBX2. Finally, in vitro functional studies were used to elucidate the effect of wild-type and variant CBX2.2 on selected downstream targets. Results Here, we describe two patients with features of DSD i.e. atypical external genitalia, perineal hypospadias and no palpable gonads, each patient carrying a distinct CBX2.2 variant, p.Cys132Arg (c.394T>C) and p.Cys154fs (c.460delT). We show that both CBX2.2 variants fail to regulate the expression of genes essential for sexual development, leading to a severe 46,XY DSD defect, likely because of a defective expression of EMX2 in the developing gonad. Conclusion Our study indicates a distinct function of the shorter form of CBX2 and by identifying several of its unique targets, can advance our understanding of DSD pathogenesis and ultimately DSD diagnosis and management.

Broad Phenotypes of Disorders/Differences of Sex Development in MAMLD1 Patients Through Oligogenic Disease.

Disorders/differences of sex development (DSD) are the result of a discordance between chromosomal, gonadal, and genital sex. DSD may be due to mutations in any of the genes involved in sex determination and development in general, as well as gonadal and/or genital development specifically. MAMLD1 is one of the recognized DSD genes. However, its role is controversial as some MAMLD1 variants are present in normal individuals, several MAMLD1 mutations have wild-type activity in functional studies, and the Mamld1-knockout male mouse presents with normal genitalia and reproduction. We previously tested nine MAMLD1 variants detected in nine 46,XY DSD patients with broad phenotypes for their functional activity, but none of the mutants, except truncated L210X, had diminished transcriptional activity on known target promoters CYP17A1 and HES3. In addition, protein expression of MAMLD1 variants was similar to wild-type, except for the truncated L210X. We hypothesized that MAMLD1 variants may not be sufficient to explain the phenotype in 46,XY DSD individuals, and that further genetic studies should be performed to search for additional hits explaining the broad phenotypes. We therefore performed whole exome sequencing (WES) in seven of these 46,XY patients with DSD and in one 46,XX patient with ovarian insufficiency, who all carried MAMLD1 variants. WES data were filtered by an algorithm including disease-tailored lists of MAMLD1-related and DSD-related genes. Fifty-five potentially deleterious variants in 41 genes were identified; 16/55 variants were reported in genes in association with hypospadias, 8/55 with cryptorchidism, 5/55 with micropenis, and 13/55 were described in relation with female sex development. Patients carried 1-16 variants in 1-16 genes together with their MAMLD1 variation. Network analysis of the identified genes revealed that 23 genes presented gene/protein interactions with MAMLD1. Thus, our study shows that the broad phenotypes of individual DSD might involve multiple genetic variations contributing towards the complex network of sexual development.

Sex Assignment and Diagnostics in Infants with Ambiguous Genitalia - A Single-Center Retrospective Study

Ambiguous genitalia affect 1 in 5,000 live births. Diagnostic procedures can be time-consuming, and often the etiology cannot be established in this group of individuals with differences/disorders of sex development (DSD). We aimed to evaluate the clinical presentation, sex assignment, and diagnostic workup in these patients. In this retrospective observational study, we included infants who presented with ambiguous genitalia from 2006 to 2016 at the Radboudumc (Radboud University Medical Center) DSD expert center. Relevant data were collected from patient records. Sixty-two 46,XY and fourteen 46,XX individuals were included. Sex was assigned in the first days of life and based on the combination of presence or absence of a uterus on ultrasound, AMH level, palpable gonads, and the karyotype (corresponded in 96% of the patients). In 86% of the 46,XX DSD subjects, a diagnosis was made, whereas in only 15/62 (24%) of the 46,XY DSD individuals, etiology was determined. In 52 individuals, genetic testing was performed resulting in a diagnosis in 24 patients (46%). AMH, hCG-stimulated testosterone, and dihydrotestosterone levels contributed to determining etiology, whilst basal testosterone and basal dihydrotestosterone did not. Establishing a diagnosis in infants with ambiguous genitalia is complex and challenging; this study aids to enhance this process and improve current practice.

Management of 46,XY Differences/Disorders of Sex Development (DSD) Throughout Life.

Differences/disorders of sex development (DSD) are a heterogeneous group of congenital conditions that result in discordance between an individual's sex chromosomes, gonads, and/or anatomic sex. Advances in the clinical care of patients and families affected by 46,XY DSD have been achieved since publication of the original Consensus meeting in 2006. The aims of this paper are to review what is known about morbidity and mortality, diagnostic tools and timing, sex of rearing, endocrine and surgical treatment, fertility and sexual function, and quality of life in people with 46,XY DSD. The role for interdisciplinary health care teams, importance of establishing a molecular diagnosis, and need for research collaborations using patient registries to better understand long-term outcomes of specific medical and surgical interventions are acknowledged and accepted. Topics that require further study include prevalence and incidence, understanding morbidity and mortality as these relate to specific etiologies underlying 46,XY DSD, appropriate and optimal options for genitoplasty, long-term quality of life, sexual function, involvement with intimate partners, and optimizing fertility potential.

Genetic Evidence of the Association of DEAH-Box Helicase 37 Defects With 46,XY Gonadal Dysgenesis Spectrum.

46,XY Gonadal dysgenesis (GD) is a heterogeneous group of disorders with a wide phenotypic spectrum, including embryonic testicular regression syndrome (ETRS). To report a gene for 46,XY GD etiology, especially for ETRS. Screening of familial cases of 46,XY GD using whole-exome sequencing and sporadic cases by target gene-panel sequencing. Tertiary Referral Center for differences/disorders of sex development (DSD). We selected 87 patients with 46,XY DSD (17 familial cases from 8 unrelated families and 70 sporadic cases); 55 patients had GD (among them, 10 patients from 5 families and 8 sporadic cases had ETRS), and 32 patients had 46,XY DSD of unknown etiology. We identified four heterozygous missense rare variants, classified as pathogenic or likely pathogenic in the Asp-Glu-Ala-His-box (DHX) helicase 37 (DHX37) gene in five families (n = 11 patients) and in six sporadic cases. Two variants were recurrent: p.Arg308Gln (in two families and in three sporadic cases) and p.Arg674Trp (in two families and in two sporadic cases). The variants were specifically associated with ETRS (7/14 index cases; 50%). The frequency of rare, predicted-to-be-deleterious DHX37 variants in this cohort (14%) is significantly higher than that observed in the Genome Aggregation Database (0.4%; P < 0.001). Immunohistochemistry analysis in human testis showed that DHX37 is mainly expressed in germ cells at different stages of testis maturation, in Leydig cells, and rarely in Sertoli cells. This strong genetic evidence identifies DHX37 as a player in the complex cascade of male gonadal differentiation and maintenance.

Female hyperandrogenism and elite sport

Emerging evidence indicates that testosterone, which can increase muscle mass and strength, stimulates erythropoiesis, promotes competitive behaviour, and enhances the physical performance of women. Indeed, the levels of testosterone within the normal female range are related to muscle mass and athletic performance in female athletes. Furthermore, among these athletes, the prevalence of hyperandrogenic conditions, including both polycystic ovary syndrome and rare differences/disorders of sex development (DSD), which may greatly increase testosterone production, are elevated. Thus, if the androgen receptors of an individual with XY DSD are functional, her muscle mass will develop like that of a man. These findings have led to the proposal that essential hyperandrogenism is beneficial for athletic performance and plays a role in the choice by women to compete in athletic activities. Moreover, a recent randomized controlled trial demonstrated a significant increase in the lean mass and aerobic performance by young exercising women when their testosterone levels were enhanced moderately. Circulating testosterone is considered the strongest factor to explain the male advantage in sport performance, ranging between 10 and 20%. It appears to be unfair to allow female athletes with endogenous testosterone levels in the male range (i.e. 10-20 times higher than normal) to compete against those with normal female androgen levels. In 2012, this consideration led international organizations to establish eligibility regulations for the female classification in order to ensure fair and meaningful competition, but the regulations are controversial and have been challenged in court.

Functional analysis of novel desert hedgehog gene variants improves the clinical interpretation of genomic data and provides a more accurate diagnosis for patients with 46,XY differences of sex development

BackgroundDesert hedgehog (DHH) gene variants are known to cause 46,XY differences/disorders of sex development (DSD). We have identified six patients with 46,XY DSD with seven novel DHH gene variants. Many...

Assembling the jigsaw puzzle: CBX2 isoform 2 and its targets in disorders/differences of sex development

BackgroundOne of the defining moments of human life occurs early during embryonic development, when individuals sexually differentiate into either male or female. Perturbation of this process can lead to disorders/differences of sex development (DSD). Chromobox protein homolog 2 (CBX2) has two distinct isoforms, CBX2.1 and CBX2.2: the role of CBX2.1 in DSD has been previously established, yet to date the function of the smaller isoform CBX2.2 remains unknown.MethodsThe genomic DNA of two 46,XY DSD patients was analysed using whole exome sequencing. Furthermore, protein/DNA interaction studies were performed using DNA adenine methyltransferase identification (DamID) to identify putative binding partners of CBX2. Finally, in vitro functional studies were used to elucidate the effect of wild‐type and variant CBX2.2 on selected downstream targets.ResultsHere, we describe two patients with features of DSD i.e. atypical external genitalia, perineal hypospadias and no palpable gonads, each patient carrying a distinct CBX2.2 variant, p.Cys132Arg (c.394T>C) and p.Cys154fs (c.460delT). We show that both CBX2.2 variants fail to regulate the expression of genes essential for sexual development, leading to a severe 46,XY DSD defect, likely because of a defective expression of EMX2 in the developing gonad.ConclusionOur study indicates a distinct function of the shorter form of CBX2 and by identifying several of its unique targets, can advance our understanding of DSD pathogenesis and ultimately DSD diagnosis and management.

Participation of adults with disorders/differences of sex development (DSD) in the clinical study dsd-LIFE: design, methodology, recruitment, data quality and study population

Backgrounddsd-LIFE is a comprehensive cross-sectional clinical outcome study of individuals with disorders/differences of sex development (DSD). This study focuses on various rare genetic conditions characterized by impaired gonadal or adrenal functionality.Methods/DesignThe study aims to assess quality of life (QoL) as a measure of psychosocial adaptation, psychosexual and mental health aspects as major outcomes. Health status and functioning, medical and surgical therapies, participants’ views on health care, psychological and social support, sociodemographic factors and their interrelations will be investigated as factors associated with the outcomes. In addition, ethical considerations in the field of DSD are addressed and previous experiences with health care were gathered. One thousand and forty participants with different DSD conditions were recruited by 14 study centres in 6 European countries (France, Germany, the Netherlands, Poland, Sweden and the United Kingdom) from February 2014 until September 2015. The conditions included were: Turner syndrome (n = 301); 45,X0/46,XY conditions (n = 45); Klinefelter syndrome (n = 218); 47,XYY (n = 1); 46,XY gonadal dysgenesis/ovotestes (n = 63); complete androgen insensitivity (CAIS) (n = 71); partial androgen insensitivity (PAIS) (n = 35) and androgen synthesis disorders (n = 20); severe hypospadias (n = 25); other or non-classified 46,XY DSD (n = 8); 46,XX congenital adrenal hyperplasia (CAH) (n = 226); 46,XX gonadal dysgenesis/ovotestis (n = 21); and 46,XX in males (n = 6). For an add-on study, 121 46,XY male-assigned individuals with CAH due to 21-hydroxylase deficiency were recruited. Mean age of participants’ was 32.4 (+/− 13.6 years).DiscussionParticipation was high in conditions not commonly described as DSD, such as Turner and Klinefelter syndromes or CAH. Recruitment of individuals with XY DSD conditions proved to be more difficult. The data collection of PROs resulted in high data quality. Within medical and physical examination data, more missings and/or inaccurate data were found than expected. The European dsd-LIFE study recruited and evaluated the largest cross-sectional sample of individuals with different conditions classified under the term DSD. The data from this large sample will provide a sufficient basis for evidence-based recommendations for improvement of clinical care of individuals affected by a DSD condition.Trial registrationGerman Clinical Trials Register DRKS00006072.

Health-related quality of life and psychological well-being in adults with differences/disorders of sex development.

Rare congenital conditions with incongruence of chromosomal, gonadal and phenotypic sex have been classified as differences/disorders of sex development (DSD). Included in DSD are conditions with diverse genetic aetiology, varying levels of prenatal androgen effects, phenotypes and, subsequently, different medical treatments. Quality of life (QoL) and psychological well-being are indicators of successful psychosocial adaptation to the conditions. We sought to investigate the HRQoL and psychological well-being in this population. This multicentre clinical evaluation study was part of a German network related to DSD funded by the German Ministry of Science and Education (BMBF 2003 to 2007). To assess health-related quality of life (HRQoL), we used the Short Form Health Survey (SF-36), and for psychological well-being, the Brief Symptom Inventory (BSI). Participants were classified into five groups: females with CAH, females with XY DSD conditions where there is a partial androgen effect (partial androgen insensitivity, mixed/partial gonadal dysgenesis, disorders of androgen biosynthesis), females with XY DSD without androgen effect (complete androgen insensitivity, complete gonadal dysgenesis), males with XY DSD, and individuals with DSD conditions and other gender. Participants included 110 adults with DSD (age range 17-62). We found a trend of lowered mental HRQoL and significant higher physical HRQoL for participants as compared to the norm. The high physical HRQoL especially applied to females with androgen effect and XY karyotype. Participants reported significant higher psychological distress compared to the norm. Forty-seven participants (42·7%) reported distress in a clinically relevant range on the BSI. Although we did not find significant impairments in overall HRQoL, participants reported significant impaired psychological well-being. Specialized interdisciplinary care should focus in particular on psychological issues to ensure good overall health and well-being.