NR5A1 is a novel disease gene for 46,XX testicular and ovotesticular disorders of sex development

Identification of a novel homozygous NR5A1 variant in a patient with a 46,XY disorders of sex development

OBJECTIVES

Nuclear receptor subfamily 5 group A member 1 (NR5A1) is a transcription factor critical for the development of various organs. Pathogenic variants in NR5A1 are associated with a spectrum of disorders of sex development (DSD).

CASE PRESENTATION

A 15-month-old baby, raised as a girl, was referred for genital swelling and ambiguous genitalia. Born to healthy consanguineous parents, the baby had a phallus, perineal hypospadias, labial fusion, and a hypoplastic scrotum. Hormonal evaluation showed normal levels, and ultrasonography revealed small gonads and absence of Müllerian derivatives. Post-human chorionic gonadotropin (hCG) testing indicated an adequate testosterone response. The karyotype was 46,XY, and in it was found a homozygous NR5A1 variant (c.307 C>T, p.Arg103Trp) in a custom 46 XY DSD gene panel. Notably, the patient exhibited complete sex reversal, hyposplenia, and no adrenal insufficiency.

CONCLUSIONS

Previously, NR5A1 pathogenic variants were considered to be dominantly inherited, and homozygous cases were thought to be associated with adrenal insufficiency. Despite the homozygous pathogenic variant, our patient showed hyposplenism with normal adrenal function; this highlights the complexity of NR5A1 genotype-phenotype correlations. These patients should be monitored for adrenal insufficiency and DSD as well as splenic function.

46,XX Differences of Sex Development outside congenital adrenal hyperplasia: pathogenesis, clinical aspects, puberty, sex hormone replacement therapy and fertility outcomes

The term 'differences of sex development' (DSD) refers to a group of congenital conditions that are associated with atypical development of chromosomal, gonadal, and/or anatomical sex. DSD in individuals with a 46,XX karyotype can occur due to fetal or postnatal exposure to elevated amount of androgens or maldevelopment of internal genitalia. Clinical phenotype could be quite variable and for this reason these conditions could be diagnosed at birth, in newborns with atypical genitalia, but also even later in life, due to progressive virilization during adolescence, or pubertal delay. Understand the physiological development and the molecular bases of gonadal and adrenal structures is crucial to determine the diagnosis and best management and treatment for these patients. The most common cause of DSD in 46,XX newborns is congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, determining primary adrenal insufficiency and androgen excess. In this review we will focus on the other rare causes of 46,XX DSD, outside CAH, summarizing the most relevant data on genetic, clinical aspects, puberty and fertility outcomes of these rare diseases.

Diagnosis and management of non-CAH 46,XX disorders/differences in sex development

Prenatal-onset androgen excess leads to abnormal sexual development in 46,XX individuals. This androgen excess can be caused endogenously by the adrenals or gonads or by exposure to exogenous androgens. The most common cause of 46,XX disorders/differences in sex development (DSD) is congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, comprising >90% of 46,XX DSD cases. Deficiencies of 11β-hydroxylase, 3β-hydroxysteroid dehydrogenase, and P450-oxidoreductase (POR) are rare types of CAH, resulting in 46,XX DSD. In all CAH forms, patients have normal ovarian development. The molecular genetic causes of 46,XX DSD, besides CAH, are uncommon. These etiologies include primary glucocorticoid resistance (PGCR) and aromatase deficiency with normal ovarian development. Additionally, 46,XX gonads can differentiate into testes, causing 46,XX testicular (T) DSD or a coexistence of ovarian and testicular tissue, defined as 46,XX ovotesticular (OT)-DSD. PGCR is caused by inactivating variants in NR3C1, resulting in glucocorticoid insensitivity and the signs of mineralocorticoid and androgen excess. Pathogenic variants in the CYP19A1 gene lead to aromatase deficiency, causing androgen excess. Many genes are involved in the mechanisms of gonadal development, and genes associated with 46,XX T/OT-DSD include translocations of the SRY; copy number variants in NR2F2, NR0B1, SOX3, SOX9, SOX10, and FGF9, and sequence variants in NR5A1, NR2F2, RSPO1, SOX9, WNT2B, WNT4, and WT1. Progress in cytogenetic and molecular genetic techniques has significantly improved our understanding of the etiology of non-CAH 46,XX DSD. Nonetheless, uncertainties about gonadal function and gender outcomes may make the management of these conditions challenging. This review explores the intricate landscape of diagnosing and managing these conditions, shedding light on the unique aspects that distinguish them from other types of DSD.

Role of NR5A1 Gene Mutations in Disorders of Sex Development: Molecular and Clinical Features

Disorders/differences of sex development (DSDs) are defined as broad, heterogenous groups of congenital conditions characterized by atypical development of genetic, gonadal, or phenotypic sex accompanied by abnormal development of internal and/or external genitalia. NR5A1 gene mutation is one of the principal genetic alterations implicated in causing DSD. This review outlines the role of NR5A1 gene during the process of gonadal development in humans, provides an overview of the molecular and functional characteristics of NR5A1 gene, and discusses potential clinical phenotypes and additional organ diseases due to NR5A1 mutations. NR5A1 mutations were analyzed in patients with 46,XY DSD and 46,XX DSD both during the neonatal and pubertal periods. Loss of function of the NR5A1 gene causes several different phenotypes, including some associated with disease in additional organs. Clinical phenotypes may vary, even among patients carrying the same NR5A1 variant, indicating that there is no specific genotype-phenotype correlation. Genetic tests are crucial diagnostic tools that should be used early in the diagnostic pathway, as early as the neonatal period, when gonadal dysgenesis is the main manifestation of NR5A1 mutation. NR5A1 gene mutations could be mainly associated with amenorrhea, ovarian failure, hypogonadism, and infertility during puberty. Fertility preservation techniques should be considered as early as possible.

Spleen function is reduced in individuals with NR5A1 variants with or without a difference of sex development: a cross-sectional study

OBJECTIVE

NR5A1 is a key regulator of sex differentiation and has been implicated in spleen development through transcription activation of TLX1. Concerns exist about hypo- or asplenism in individuals who have a difference of sex development (DSD) due to an NR5A1 disease-causing variant. We aimed to assess spleen anatomy and function in a clinical cohort of such individuals and in their asymptomatic family member carriers.

DESIGN

Cross-sectional assessment in 22 patients with a DSD or primary ovarian insufficiency and 5 asymptomatic carriers from 18 families, harboring 14 different NR5A1 variants.

METHODS

Spleen anatomy was assessed by ultrasound, spleen function by peripheral blood cell count, white blood cell differentiation, percentage of nonswitched memory B cells, specific pneumococcal antibody response, % pitted red blood cells, and Howell-Jolly bodies.

RESULTS

Patients and asymptomatic heterozygous individuals had significantly decreased nonswitched memory B cells compared to healthy controls, but higher than asplenic patients. Thrombocytosis and spleen hypoplasia were present in 50% of heterozygous individuals. Four out of 5 individuals homozygous for the previously described p.(Arg103Gln) variant had asplenia.

CONCLUSIONS

Individuals harboring a heterozygous NR5A1 variant that may cause DSD have a considerable risk for functional hyposplenism, irrespective of their gonadal phenotype. Splenic function should be assessed in these individuals, and if affected or unknown, prophylaxis is recommended to prevent invasive encapsulated bacterial infections. The splenic phenotype associated with NR5A1 variants is more severe in homozygous individuals and is, at least for the p.(Arg103Gln) variant, associated with asplenism.

Clinical and genetic characteristics of a large international cohort of individuals with rare NR5A1/SF-1 variants of sex development

BACKGROUND

Steroidogenic factor 1 (SF-1/NR5A1) is essential for human sex development. Heterozygous NR5A1/SF-1 variants manifest with a broad range of phenotypes of differences of sex development (DSD), which remain unexplained.

METHODS

We conducted a retrospective analysis on the so far largest international cohort of individuals with NR5A1/SF-1 variants, identified through the I-DSD registry and a research network.

FINDINGS

Among 197 individuals with NR5A1/SF-1 variants, we confirmed diverse phenotypes. Over 70% of 46, XY individuals had a severe DSD phenotype, while 90% of 46, XX individuals had female-typical sex development. Close to 100 different novel and known NR5A1/SF-1 variants were identified, without specific hot spots. Additionally, likely disease-associated variants in other genes were reported in 32 individuals out of 128 tested (25%), particularly in those with severe or opposite sex DSD phenotypes. Interestingly, 48% of these variants were found in known DSD or SF-1 interacting genes, but no frequent gene-clusters were identified. Sex registration at birth varied, with <10% undergoing reassignment. Gonadectomy was performed in 30% and genital surgery in 58%. Associated organ anomalies were observed in 27% of individuals with a DSD, mainly concerning the spleen. Intrafamilial phenotypes also varied considerably.

INTERPRETATION

The observed phenotypic variability in individuals and families with NR5A1/SF-1 variants is large and remains unpredictable. It may often not be solely explained by the monogenic pathogenicity of the NR5A1/SF-1 variants but is likely influenced by additional genetic variants and as-yet-unknown factors.

FUNDING

Swiss National Science Foundation (320030-197725) and Boveri Foundation Zürich, Switzerland.

A Novel Variant in NR5A1 Presenting as 46,XY Difference of Sex Development

Differences of sex development (DSDs) are a spectrum of congenital clinical conditions involving the development of gonadal, chromosomal, and anatomical sex. The physical presentation provides incomplete clues because underlying etiologies may present with similar findings. We describe an 8-year-old boy from the Dominican Republic originally diagnosed with congenital adrenal hyperplasia (CAH). He was prescribed oral hydrocortisone and fludrocortisone, with irregular adherence. During infancy, he had human chorionic gonadotropin injections to stimulate phallic growth. After migrating to the United States, medications became depleted but without adrenal crisis. Laboratory testing with high-dose adrenocorticotropin stimulation study ruled out CAH. Careful examination noted an underdeveloped bifid scrotum, bilaterally undescended testicles, a 2-cm phallus, severe penoscrotal hypospadias, and chordee. Subsequently, he had a 2-stage bilateral orchiopexy and surgical repair of penoscrotal hypospadias and chordee. Genetic testing for 46,XY DSD revealed a novel, dominant, heterozygous, likely pathogenic variant (c.102 + 1G > C) in the NR5A1 gene associated with severe phenotype of undervirilized male. This case illustrates the crucial role of molecular genetic testing for the diagnosis of 46,XY DSDs and a novel NR5A1 gene variant.

Nuclear Receptor Gene Variants Underlying Disorders/Differences of Sex Development through Abnormal Testicular Development

Gonadal development is the first step in human reproduction. Aberrant gonadal development during the fetal period is a major cause of disorders/differences of sex development (DSD). To date, pathogenic variants of three nuclear receptor genes (NR5A1, NR0B1, and NR2F2) have been reported to cause DSD via atypical testicular development. In this review article, we describe the clinical significance of the NR5A1 variants as the cause of DSD and introduce novel findings from recent studies. NR5A1 variants are associated with 46,XY DSD and 46,XX testicular/ovotesticular DSD. Notably, both 46,XX DSD and 46,XY DSD caused by the NR5A1 variants show remarkable phenotypic variability, to which digenic/oligogenic inheritances potentially contribute. Additionally, we discuss the roles of NR0B1 and NR2F2 in the etiology of DSD. NR0B1 acts as an anti-testicular gene. Duplications containing NR0B1 result in 46,XY DSD, whereas deletions encompassing NR0B1 can underlie 46,XX testicular/ovotesticular DSD. NR2F2 has recently been reported as a causative gene for 46,XX testicular/ovotesticular DSD and possibly for 46,XY DSD, although the role of NR2F2 in gonadal development is unclear. The knowledge about these three nuclear receptors provides novel insights into the molecular networks involved in the gonadal development in human fetuses.

Genetic control of typical and atypical sex development

Sex development relies on the sex-specific action of gene networks to differentiate the bipotential gonads of the growing fetus into testis or ovaries, followed by the differentiation of internal and external genitalia depending on the presence or absence of hormones. Differences in sex development (DSD) arise from congenital alterations during any of these processes, and are classified depending on sex chromosomal constitution as sex chromosome DSD, 46,XY DSD or 46,XX DSD. Understanding the genetics and embryology of typical and atypical sex development is essential for diagnosing, treating and managing DSD. Advances have been made in understanding the genetic causes of DSD over the past 10 years, especially for 46,XY DSD. Additional information is required to better understand ovarian and female development and to identify further genetic causes of 46,XX DSD, besides congenital adrenal hyperplasia. Ongoing research is focused on the discovery of further genes related to typical and atypical sex development and, therefore, on improving diagnosis of DSD.

A Novel NR5A1 Mutation in a Thai Boy with 46, XY DSD

Disorders of sex development (DSD) can be classified as 46,XX DSD, 46,XY DSD, and sex chromosome DSD. Several underlying causes including associated genes have been reported. Steroidogenic factor-1 is encoded by the NR5A1 gene, a crucial regulator of steroidogenesis in the growth of the adrenal and gonadal tissues. It has been discovered to be responsible for 10 to 20% of 46, XY DSD cases. Here, we described a 2-month-old infant who had ambiguous genitalia and 46, XY. Using whole exome sequencing followed by polymerase chain reaction–Sanger sequencing, a novel heterozygous nonsense c.1249C > T (p.Gln417Ter) variant in the NR5A1 gene was identified. It is present in his mother but absent in his father and maternal aunt and uncle. At the age of 7 months, the patient received a monthly intramuscular injection of low-dose testosterone for 3 months in a row. His penile length and diameter increased from 1.8 to 3 cm and from 0.8 to 1.3 cm, respectively. The patient also had normal adrenal reserve function by adrenocorticotropic hormone stimulation test. This study identified a novel causative p.Q417X (c.1249C > T) variant in NR5A1 causing 46,XY DSD in a Thai boy which is inherited from his unaffected mother.

A Rare Differences of Sex Development: Male Sex Reversal Syndrome (NonSyndromic 46, XX with Negative Sex-Determining Region of Y Chromosome Gene)

46, XX testicular differences of sex development (DSD) is a rare cause of DSD presenting as a phenotypical male with chromosomal sex of 46, XX. Sex-determining region of the Y chromosome (SRY)-positive 46, XX DSDs have a well-characterized pathogenetic mechanism, whereas in SRY-negative 46, XX DSDs, the pathogenesis is not clearly delineated. Herein, we present a case of a 3½-year-old child who presented with ambiguous genitalia and bilateral palpable gonads. On the basis of a karyotype and fluorescent in situ hybridization, we arrived at a diagnosis of SRY-negative 46, XX testicular DSD. Basal serum estradiol and human menopausal gonadotrophin stimulated estradiol levels and inhibin A blood levels were against the presence of any ovarian tissue. Imaging of the gonads showed bilateral normal-looking testis. A clinical exome sequencing revealed a heterozygous missense variant NR5A1:c275G>A (p. Arg92gln) located at exon 4 in the affected child. Protein structure analysis was further performed, and the variant was found to be highly conserved. Sanger's sequencing showed that the mother was heterozygous for the variant detected in the child. This case highlights the rarity of SRY-negative 46, XX testicular DSD with a unique variant. Largely under characterized, this group of DSDs needs to be reported and analyzed to add to the spectrum of presentation and genetic characteristics. Our case is expected to add to the database, knowledge, and approach to cases of 46, XX testicular DSD.

Becoming female: Ovarian differentiation from an evolutionary perspective

Differentiation of the bipotential gonadal primordium into ovaries and testes is a common process among vertebrate species. While vertebrate ovaries eventually share the same functions of producing oocytes and estrogens, ovarian differentiation relies on different morphogenetic, cellular, and molecular cues depending on species. The aim of this review is to highlight the conserved and divergent features of ovarian differentiation through an evolutionary perspective. From teleosts to mammals, each clade or species has a different story to tell. For this purpose, this review focuses on three specific aspects of ovarian differentiation: ovarian morphogenesis, the evolution of the role of estrogens on ovarian differentiation and the molecular pathways involved in granulosa cell determination and maintenance.

Rare forms of genetic steroidogenic defects affecting the gonads and adrenals

Pathogenic variants have been found in all genes involved in the classic pathways of human adrenal and gonadal steroidogenesis. Depending on their function and severity, they cause characteristic disorders of corticosteroid and/or sex hormone deficiency, may result in atypical sex development at birth and/or puberty, and mostly lead to sexual dysfunction and infertility. Genetic disorders of steroidogenesis are all inherited in an autosomal recessive fashion. Loss of function mutations lead to typical phenotypes, while variants with partial activity may manifest with milder, non-classic, late-onset disorders that share similar phenotypes. Thus, these disorders of steroidogenesis are diagnosed by comprehensive phenotyping, steroid profiling and genetic testing using next generation sequencing techniques. Treatment comprises of steroid replacement therapies, but these are insufficient in many aspects. Therefore, studies are currently ongoing towards newer approaches such as lentiviral transmitted enzyme replacement therapy and reprogrammed stem cell-based gene therapy.

Monogenic forms of DSD: An update

DSD encompasses a wide range of pathologies that impact gonad formation, development and function in both 46,XX and 46,XY individuals. The majority of these conditions are considered to be monogenic, although the expression of the phenotype may be influenced by genetic modifiers. Although considered monogenic, establishing the genetic etiology in DSD has been difficult compared to other congenital disorders for a number of reasons including the absence of family cases for classical genetic association studies and the lack of evolutionary conservation of key genetic factors involved in gonad formation. In recent years, the widespread use of genomic sequencing technologies has resulted in multiple genes being identified and proposed as novel monogenic causes of 46,XX and/or 46,XY DSD. In this review, we will focus on the main genomic findings of recent years, which consists of new candidate genes or loci for DSD as well as new reproductive phenotypes associated with genes that are well established to cause DSD. For each gene or loci, we summarise the data that is currently available in favor of or against a role for these genes in DSD or the contribution of genomic variants within well-established genes to a new reproductive phenotype. Based on this analysis we propose a series of recommendations that should aid the interpretation of genomic data and ultimately help to improve the accuracy and yield genetic diagnosis of DSD.

Genetics of human sexual development and related disorders

PURPOSE OF REVIEW

The aim of this study was to provide a basic overview on human sex development with a focus on involved genes and pathways, and also to discuss recent advances in the molecular diagnostic approaches applied to clinical workup of individuals with a difference/disorder of sex development (DSD).

RECENT FINDINGS

Rapid developments in genetic technologies and bioinformatics analyses have helped to identify novel genes and genomic pathways associated with sex development, and have improved diagnostic algorithms to integrate clinical, hormonal and genetic data. Recently, massive parallel sequencing approaches revealed that the phenotype of some DSDs might be only explained by oligogenic inheritance.

SUMMARY

Typical sex development relies on very complex biological events, which involve specific interactions of a large number of genes and pathways in a defined spatiotemporal sequence. Any perturbation in these genetic and hormonal processes may result in atypical sex development leading to a wide range of DSDs in humans. Despite the huge progress in the understanding of molecular mechanisms underlying DSDs in recent years, in less than 50% of DSD individuals, the genetic cause is currently solved at the molecular level.

MAMLD1 and Differences/Disorders of Sex Development: An Update

MAMLD1 (alias CXorf6) was first documented in 2006 as a causative gene of 46,XY differences/disorders of sex development (DSD). MAMLD1/Mamld1 is expressed in the fetal testis and is predicted to enhance the expression of several Leydig cell-specific genes. To date, hemizygous MAMLD1 variants have been identified in multiple 46,XY individuals with hypomasculinized external genitalia. Pathogenic MAMLD1 variants are likely to cause genital abnormalities at birth and are possibly associated with age-dependent deterioration of testicular function. In addition, some MAMLD1 variants have been identified in 46,XX individuals with ovarian dysfunction. However, recent studies have raised the possibility that MAMLD1 variants cause 46,XY DSD and ovarian dysfunction as oligogenic disorders. Unsolved issues regarding MAMLD1 include the association between MAMLD1 variants and 46,XX testicular DSD, gene-gene interactions in the development of MAMLD1-mediated DSD, and intracellular functions of MAMLD1.

Towards improved genetic diagnosis of human differences of sex development

Despite being collectively among the most frequent congenital developmental conditions worldwide, differences of sex development (DSD) lack recognition and research funding. As a result, what constitutes optimal management remains uncertain. Identification of the individual conditions under the DSD umbrella is challenging and molecular genetic diagnosis is frequently not achieved, which has psychosocial and health-related repercussions for patients and their families. New genomic approaches have the potential to resolve this impasse through better detection of protein-coding variants and ascertainment of under-recognized aetiology, such as mosaic, structural, non-coding or epigenetic variants. Ultimately, it is hoped that better outcomes data, improved understanding of the molecular causes and greater public awareness will bring an end to the stigma often associated with DSD.

Ovotesticular Difference of Sex Development: Genetic Background, Histological Features, and Clinical Management

BACKGROUND

Ovotesticular disorder/difference of sex development (DSD) refers to the co-presence of testicular and ovarian tissue in one individual. Childhood management is challenging as there are many uncertainties regarding etiology, gonadal function, and gender outcome.

SUMMARY

Ovotesticular DSD should mainly be considered in 46,XX children with atypical genitalia and normal adrenal steroid profiles. Various underlying genetic mechanisms have been described. Histological assessment of ovotestes requires expert revision and has many pitfalls. Neonatal sex assignment is essential, but as gender outcome is unpredictable, this should be regarded as provisional until a stable gender identity has developed. Therefore, it is crucial not to perform any irreversible medical or surgical procedure in affected individuals until adolescents can give their full informed consent. Gonadal function mostly allows for spontaneous pubertal development; however, fertility is compromised, especially in boys. Specific long-term outcome data for ovotesticular DSD are lacking but can be extrapolated from studies in other DSD populations. Key Messages: Management of ovotesticular DSD has changed in recent years, prioritizing the child's future right for autonomy and self-determination. The benefits and pitfalls of this new approach have not been documented yet and require intensive monitoring on an international scale.

Constitutive expression of Steroidogenic factor-1 (NR5A1) disrupts ovarian functions, fertility, and metabolic homeostasis in female mice

Steroid hormones regulate various aspects of physiology, from reproductive functions to metabolic homeostasis. Steroidogenic factor-1 (NR5A1) plays a central role in the development of steroidogenic tissues and their ability to produce steroid hormones. Inactivation of Nr5a1 in the mouse results in a complete gonadal and adrenal agenesis, absence of gonadotropes in the pituitary and impaired development of ventromedial hypothalamus, which controls glucose and energy metabolism. In this study, we set out to examine the consequences of NR5A1 overexpression (NR5A1+) in the NR5A1-positive cell populations in female mice. Ovaries of NR5A1+ females presented defects such as multi-oocyte follicles and an accumulation of corpora lutea. These females were hyperandrogenic, had irregular estrous cycles with persistent metestrus and became prematurely infertile. Furthermore, the decline in fertility coincided with weight gain, increased adiposity, hypertriglyceridemia, hyperinsulinemia, and impaired glucose tolerance, indicating defects in metabolic functions. In summary, excess NR5A1 expression causes hyperandrogenism, disruption of ovarian functions, premature infertility, and disorders of metabolic homeostasis. This NR5A1 overexpression mouse provides a novel model for studying not only the molecular actions of NR5A1, but also the crosstalk between endocrine, reproductive, and metabolic systems.

Characteristics and possible mechanisms of 46, XY differences in sex development caused by novel compound variants in NR5A1 and MAP3K1

Background

Dozens of genes are involved in 46, XY differences in sex development (DSD). Notably, about 3/4 of patients cannot make a clear etiology diagnosis and single gene variant identified cannot fully explain the clinical heterogeneity of 46, XY DSD.

Materials and methods

We conducted a systematic clinical analysis of a 46, XY DSD patient, and applied whole-exome sequencing for the genetic analysis of this pedigree. The identified variants were analyzed by bioinformatic analysis and in vitro studies were performed in human embryonic kidney 293T (HEK-293T) cells which were transiently transfected with wild type or variant NR5A1 and MAP3K1 plasmid. Furthermore, protein production of SRY-box transcription factor 9 (SOX9) was analyzed in cell lysates.

Results

A novel NR5A1 variant (c.929A > C, p. His310Pro) and a rare MAP3K1 variant (c.2282T > C, p. Ile761Thr) were identified in the proband, whereas the proband's mother and sister who only carry rare MAP3K1 variant have remained phenotypically healthy to the present. These two variants were predicted to be pathogenic by bioinformatic analysis. In vitro, NR5A1 variant decreased the SOX9 production by 82.11% compared to wild type NR5A1, while MAP3K1 variant had little effect on the SOX9 production compared to wild type MAP3K1. Compared to wild type NR5A1 transfection, the SOX9 production of cells transfected with both wild type plasmids decreased by about 17.40%. Compared to variant NR5A1 transfection, the SOX9 production of cells transfected with both variant plasmids increased by the 36.64%.

Conclusions

Our findings suggested the novel compound variants of NR5A1 and MAP3K1 can alter the expression of SOX9 and ultimately lead to abnormality of sex development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01908-z.

Cellular fate of intersex differentiation

Infertile ovotestis (mixture of ovary and testis) often occurs in intersex individuals under certain pathological and physiological conditions. However, how ovotestis is formed remains largely unknown. Here, we report the first comprehensive single-cell developmental atlas of the model ovotestis. We provide an overview of cell identities and a roadmap of germline, niche, and stem cell development in ovotestis by cell lineage reconstruction and a uniform manifold approximation and projection. We identify common progenitors of germline stem cells with two states, which reveal their bipotential nature to differentiate into both spermatogonial stem cells and female germline stem cells. Moreover, we found that ovotestis infertility was caused by degradation of female germline cells via liquid-liquid phase separation of the proteasomes in the nucleus, and impaired histone-to-protamine replacement in spermatid differentiation. Notably, signaling pathways in gonadal niche cells and their interaction with germlines synergistically determined distinct cell fate of both male and female germlines. Overall, we reveal a cellular fate map of germline and niche cell development that shapes cell differentiation direction of ovotestis, and provide novel insights into ovotestis development.

Iprodione and chlorpyrifos induce testicular damage, oxidative stress, apoptosis and suppression of steroidogenic- and spermatogenic-related genes in immature male albino rats

The fungicide iprodione (IPR) and the insecticide chlorpyrifos (CPF) are concurrently applied for early disease control in fruits and other crops. However, there are no available data about the impacts of their co-exposure. Additionally, IPR and CPF are known as endocrine disruptors that can cause reproductive toxicity. The outcomes of their co-exposure on the development of male reproductive organs are still unknown. Therefore, this study aimed to assess the risk of exposure to these pesticides, particularly on the postnatal development of the male albino rat reproductive system from postnatal days 23-60. The results revealed that a single IPR or CPF exposure has harmful consequences on the reproductive development and function manifested by reduced testicular weight, serious changes in sperm characteristics, reproductive hormone level imbalance, testicular enzymes, oxidative stress and apoptosis-related enzymes, which correlated with transcription levels of steroidogenic- and spermatogenic-related genes. Histopathologically, both compounds caused severe damage in the testis and accessory glands architecture. Notably, co-exposure to IPR and CPF in rats caused more serious damage, indicative of an additive effect than individual exposure, so concurrent exposure should be avoided as it is more hazardous, especially on male fertility.

Identification and functional analysis of fourteen NR5A1 variants in patients with the 46 XY disorders of sex development

Human sex determination and differentiation is a complex process, during which NR5A1 plays a central role via the transcriptional regulation of key modulators involved in steroidogenesis. Approximately 8-15% of 46,XY DSD are caused by variants in the NR5A1 gene. Therefore, screening for variants in the NR5A1 gene was performed in a Chinese cohort of sixty-two 46,XY DSD patients with no AR or SRD5A2 variants via next-generation sequencing (NGS). Fourteen variants in the NR5A1 gene were identified in 16 patients from 14 unrelated families, including nine novel variants. These variants included eight heterozygote missense variants, two heterozygote frameshift variants, two heterozygote nonsense variants, one heterozygote nonframeshift deletion-insertion variant, and one homozygous missense variant. Functional assays showed that the transcriptional activity of the 11 variants was significantly reduced. In this study, 11 NR5A1 pathogenic variants were identified. These novel variants further expand the existing spectrum of the NR5A1 variants associated with 46,XY DSD, which will, in turn, assist in the molecular diagnosis of DSD.

Sex determination, gonadal sex differentiation, and plasticity in vertebrate species

A diverse array of sex determination (SD) mechanisms, encompassing environmental to genetic, have been found to exist among vertebrates, covering a spectrum from fixed SD mechanisms (mammals) to functional sex change in fishes (sequential hermaphroditic fishes). A major landmark in vertebrate SD was the discovery of the SRY gene in 1990. Since that time, many attempts to clone an SRY ortholog from nonmammalian vertebrates remained unsuccessful, until 2002, when DMY/dmrt1by was discovered as the SD gene of a small fish, medaka. Surprisingly, however, DMY/dmrt1by was found in only 2 species among more than 20 species of medaka, suggesting a large diversity of SD genes among vertebrates. Considerable progress has been made over the last 3 decades, such that it is now possible to formulate reasonable paradigms of how SD and gonadal sex differentiation may work in some model vertebrate species. This review outlines our current understanding of vertebrate SD and gonadal sex differentiation, with a focus on the molecular and cellular mechanisms involved. An impressive number of genes and factors have been discovered that play important roles in testicular and ovarian differentiation. An antagonism between the male and female pathway genes exists in gonads during both sex differentiation and, surprisingly, even as adults, suggesting that, in addition to sex-changing fishes, gonochoristic vertebrates including mice maintain some degree of gonadal sexual plasticity into adulthood. Importantly, a review of various SD mechanisms among vertebrates suggests that this is the ideal biological event that can make us understand the evolutionary conundrums underlying speciation and species diversity.

Similar Cause, Different Phenotype: SOX9 Enhancer Duplication in a Family

INTRODUCTION

46,XX ovotesticular disorder of sex development (DSD), as defined by the Chicago consensus in 2006, is characterized by histologically confirmed testicular and ovarian tissue in an individual with a 46,XX karyotype and a wide phenotypic spectrum from female to male appearance.

CASE PRESENTATION

We report the case of two 46,XX sex determining region Y (SRY) gene-negative siblings and their 46,XY father with an approximately 150 kilobase pair (kbp) duplication upstream of SOX9 (SRY-box 9) gene's transcriptional start site on chromosome 17 (chr17), which involved SOX9's minimal critical 46,XX sex reversal region. This duplication is sufficient to trigger male development in the absence of Y-chromosomal material and can lead to various degrees of masculinization in 46,XX individuals by overexpression of SOX9. Based on anamnestic information and pedigree analysis, another possible carrier of this copy number variation (CNV) could have been the father's sister.

DISCUSSION

By comparing the duplications of our two sibling patients and previously reported similar cases, we suggest that the small differences between their breakpoints could alternatively modify the inner structure and functioning of SOX9'stopologically associated domain (TAD) due to the differing fine TAD arrangements. Our data support the phenotypic modularity impact - incomplete penetrance and variable expressivity - of very similar but non-identical CNVs, which are possibly inherited across three generations.

High Molecular Diagnosis Rate in Undermasculinized Males with Differences in Sex Development Using a Stepwise Approach

Differences of sex development (DSDs) are a constellation of conditions that result in genital ambiguity or complete sex reversal. Although determining the underlying genetic variants can affect clinical management, fewer than half of undermasculinized males ever receive molecular diagnoses. Next-generation sequencing (NGS) technology has improved diagnostic capabilities in several other diseases, and a few small studies suggest that it may improve molecular diagnostic capabilities in DSDs. However, the overall diagnostic rate that can be achieved with NGS for larger groups of patients with DSDs remains unknown. In this study, we aimed to implement a tiered approach to genetic testing in undermasculinized males seen in an interdisciplinary DSD clinic to increase the molecular diagnosis rate in this group. We determined the diagnosis rate in patients undergoing all clinically available testing. Patients underwent a stepwise approach to testing beginning with a karyotype and progressing through individual gene testing, microarray, panel testing, and then to whole-exome sequencing (WES) if no molecular cause was found. Deletion/duplication studies were also done if deletions were suspected. Sixty undermasculinized male participants were seen in an interdisciplinary DSD clinic from 2008 to 2016. Overall, 37/60 (62%) of patients with Y chromosomes and 46% of those who were 46XY received molecular diagnoses. Of the 46,XY patients who underwent all available genetic testing, 18/28 (64%) achieved molecular diagnoses. This study suggests that the addition of WES testing can result in a higher rate of molecular diagnoses compared to genetic panel testing.

Under-reported aspects of diagnosis and treatment addressed in the Dutch-Flemish guideline for comprehensive diagnostics in disorders/differences of sex development

We present key points from the updated Dutch-Flemish guideline on comprehensive diagnostics in disorders/differences of sex development (DSD) that have not been widely addressed in the current (inter)national literature. These points are of interest to physicians working in DSD (expert) centres and to professionals who come across persons with a DSD but have no (or limited) experience in this area. The Dutch-Flemish guideline is based on internationally accepted principles. Recent initiatives striving for uniform high-quality care across Europe, and beyond, such as the completed COST action 1303 and the European Reference Network for rare endocrine conditions (EndoERN), have generated several excellent papers covering nearly all aspects of DSD. The Dutch-Flemish guideline follows these international consensus papers and covers a number of other topics relevant to daily practice. For instance, although next-generation sequencing (NGS)-based molecular diagnostics are becoming the gold standard for genetic evaluation, it can be difficult to prove variant causality or relate the genotype to the clinical presentation. Network formation and centralisation are essential to promote functional studies that assess the effects of genetic variants and to the correct histological assessment of gonadal material from DSD patients, as well as allowing for maximisation of expertise and possible cost reductions. The Dutch-Flemish guidelines uniquely address three aspects of DSD. First, we propose an algorithm for counselling and diagnostic evaluation when a DSD is suspected prenatally, a clinical situation that is becoming more common. Referral to ultrasound sonographers and obstetricians who are part of a DSD team is increasingly important here. Second, we pay special attention to healthcare professionals not working within a DSD centre as they are often the first to diagnose or suspect a DSD, but are not regularly exposed to DSDs and may have limited experience. Their thoughtful communication to patients, carers and colleagues, and the accessibility of protocols for first-line management and efficient referral are essential. Careful communication in the prenatal to neonatal period and the adolescent to adult transition are equally important and relatively under-reported in the literature. Third, we discuss the timing of (NGS-based) molecular diagnostics in the initial workup of new patients and in people with a diagnosis made solely on clinical grounds or those who had earlier genetic testing that is not compatible with current state-of-the-art diagnostics.

A missense mutation in NR5A1 causing female to male sex reversal: A case report

Testicular disorder of sex development (TDSD) is a rare condition, characterised by a female karyotype, male phenotype, small testes and cryptorchidism. Only a few studies have investigated the genetic causes of male sex reversal. This is the clinical report of an Iranian 46,XX patient presented with TDSD and associated with hypospadias. Whole-exome sequencing (WES) of the patient ascertained the heterozygous missense variant (c.274C>T) in the NR5A1 gene, resulting in a substitution of arginine with tryptophan. The arginine 92 residue was located in a highly conserved region of steroidogenic factor 1 (SF1), which is crucial for its interaction with DNA. Our finding is in line with previous reports, which highlighted the role of p.(Arg92Trp) variant in TDSD individuals. As far as we are aware, this is the first report of TDSD with p.(Arg92Trp) variant in the Iranian population.

Disorders of Sex Development-Novel Regulators, Impacts on Fertility, and Options for Fertility Preservation

Disorders (or differences) of sex development (DSD) are a heterogeneous group of congenital conditions with variations in chromosomal, gonadal, or anatomical sex. Impaired gonadal development is central to the pathogenesis of the majority of DSDs and therefore a clear understanding of gonadal development is essential to comprehend the impacts of these disorders on the individual, including impacts on future fertility. Gonadal development was traditionally considered to involve a primary 'male' pathway leading to testicular development as a result of expression of a small number of key testis-determining genes. However, it is increasingly recognized that there are several gene networks involved in the development of the bipotential gonad towards either a testicular or ovarian fate. This includes genes that act antagonistically to regulate gonadal development. This review will highlight some of the novel regulators of gonadal development and how the identification of these has enhanced understanding of gonadal development and the pathogenesis of DSD. We will also describe the impact of DSDs on fertility and options for fertility preservation in this context.

Functional study of a novel c.630delG (p.Y211Tfs*85) mutation in NR5A1 gene in a Chinese boy with 46,XY disorders of sex development

PURPOSE

This study aimed to present the clinical features and gene mutation characteristics of a child with 46,XY disorders of sex development (DSD) caused by a novel heterozygous mutation in the NR5A1 gene to determine the potential association between this heterozygous mutation and the pathogenesis of 46,XY DSD.

METHODS

We present the case of a Chinese child with ambiguous genitalia at birth but a normal adrenal gland. Targeted next-generation sequencing, comprising 163 candidate genes involved in sexual differentiation and development, was performed, followed by the functional evaluation of the novel NR5A1 mutation.

RESULT

The patient had a novel heterozygous mutation in the NR5A1 gene, c.630delG (p.Y211Tfs*85). Results revealed that overexpression of p.Y211Tfs*85 impaired steroidogenic factor-1 (SF-1) protein synthesis. Immunofluorescence analysis revealed that both SF-1 wild-type and p.Y211Tfs*85 mutation proteins were localized in the cell nucleus. Furthermore, dual-luciferase reporter assay results revealed that the p.Y211Tfs*85 mutation could effectively downregulate the transcriptional activation of anti-Müllerian hormone and steroidogenic acute regulatory protein genes (P < 0.01). Additionally, the p.Y211Tfs*85 mutation changed three-dimensional conformation of SF-1, and three conformations could be constructed with the mutated amino acid sequences. Therefore, the novel frameshift mutation could result in decreased protein expression of SF-1.

CONCLUSION

We described a novel mutation in NR5A1 and showed that it might affect protein structure, thereby seriously compromising the role of SF-1 in regulating gonadal development. The novel p.Y211Tfs*85 mutation in the NR5A1 gene enriches the boy of information available regarding the mutation spectrum of this gene in the Chinese population.

Primary adrenal insufficiency: New genetic causes and their long-term consequences

Primary adrenal insufficiency (PAI) is a potentially life-threatening condition that requires urgent diagnosis and treatment. Whilst the most common causes are congenital adrenal hyperplasia (CAH) in childhood and autoimmune adrenal insufficiency in adolescence and adulthood, more than 30 other physical and genetics cause of PAI have been reported. Reaching a specific diagnosis can have implications for management and for monitoring associated features, as well as for counselling families about recurrence risk in siblings and relatives. Here, we describe some recent insights into the genetics of adrenal insufficiency and associated molecular mechanisms. We discuss (a) the role of the nuclear receptors DAX-1 (NR0B1) and steroidogenic factor-1 (SF-1, NR5A1) in human adrenal and reproductive dysfunction; (b) multisystem growth restriction syndromes due to gain-of-function in the growth repressors CDKN1C (IMAGE syndrome) and SAMD9 (MIRAGE syndrome), or loss of POLE1; (c) nonclassic forms of STAR and P450scc/CYP11A1 insufficiency that present with a delayed-onset adrenal phenotype and represent a surprisingly prevalent cause of undiagnosed PAI; and (d) a new sphingolipidosis causing PAI due to defects in sphingosine-1-phosphate lyase-1 (SGPL1). Reaching a specific diagnosis can have life-long implications for management. In some situations, milder or nonclassic forms of these conditions can first present in adulthood and may have been labelled, "Addison's disease."

Male Hypogonadism and Disorders of Sex Development

Disorders of Sex Development (DSD) are congenital anomalies in which there is a discordance between chromosomal, genetic, gonadal, and/or internal/external genital sex. In XY individuals, the process of fetal sex differentiation can be disrupted at the stage of gonadal differentiation, resulting in gonadal dysgenesis, a form of early fetal-onset primary hypogonadism characterized by insufficient androgen and anti-Müllerian hormone (AMH) production, which leads to the development of ambiguous or female genitalia. The process of sex differentiation can also be disrupted at the stage of genital differentiation, due to isolated defects in androgen or AMH secretion, but not both. These are forms of fetal-onset hypogonadism with dissociated gonadal dysfunction. In this review, we present a perspective on impaired testicular endocrine function, i.e., fetal-onset male hypogonadism, resulting in incomplete virilization at birth.

In cases of familial primary ovarian insufficiency and disorders of gonadal development, consider NR5A1/SF-1 sequence variants

RESEARCH QUESTION

Primary ovarian insufficiency (POI) is defined as the early exhaustion of ovarian function, before the age of 40 years. Its origin is genetic in 20-25% of cases. In rare cases, sequence variants of the NR5A1/SF-1 gene may result in POI, or in various disorders of gonadal development (DGD) or adrenal insufficiency.

DESIGN

This study describes the cases of two families in which the association of DGD and POI enabled a diagnosis of NR5A1 deleterious variations. Their clinical, hormonal, ultrasound and genetic characteristics are reported.

RESULTS

The mothers of the affected children were 21 and 29 years when POI was diagnosed. Each nonetheless had two spontaneous pregnancies. The children have different phenotypes and different forms of DGD. None of the affected family members had adrenal insufficiency. A new sequence variant of the NR5A1 gene was identified in one family: p.Cys283Phe (c.848G>T), and the NR5A1 sequence variant c.86G>C was found in the other family.

CONCLUSION

Sequence variation of the NR5A1 gene is a possibility that must be considered when a woman with POI or a diminished ovarian reserve has a family member or child with DGD. If a variant is identified, genetic counselling is essential for the patient and his/her family.

Molecular Characterization of XX Maleness

Androgens and anti-Müllerian hormone (AMH), secreted by the foetal testis, are responsible for the development of male reproductive organs and the regression of female anlagen. Virilization of the reproductive tract in association with the absence of Müllerian derivatives in the XX foetus implies the existence of testicular tissue, which can occur in the presence or absence of SRY. Recent advancement in the knowledge of the opposing gene cascades driving to the differentiation of the gonadal ridge into testes or ovaries during early foetal development has provided insight into the molecular explanation of XX maleness.

The transcriptional regulator CBX2 and ovarian function: A whole genome and whole transcriptome approach

The chromobox homolog 2 (CBX2) was found to be important for human testis development, but its role in the human ovary remains elusive. We conducted a genome-wide analysis based on DNA adenine methyltransferase identification (DamID) and RNA sequencing strategies to investigate CBX2 in the human granulosa cells. Functional analysis revealed that CBX2 was upstream of genes contributing to ovarian function like folliculogenesis and steroidogenesis (i.e. ESR1, NRG1, AKR1C1, PTGER2, BMP15, BMP2, FSHR and NTRK1/2). We identified CBX2 regulated genes associated with polycystic ovary syndrome (PCOS) such as TGFβ, MAP3K15 and DKK1, as well as genes implicated in premature ovarian failure (POF) (i.e. POF1B, BMP15 and HOXA13) and the pituitary deficiency (i.e. LHX4 and KISS1). Our study provided an excellent opportunity to identify genes surrounding CBX2 in the ovary and might contribute to the understanding of ovarian physiopathology causing infertility in women.

Molecular cytogenetic analysis and genetic counseling: a case report of eight 46,XX males and a literature review

Background

46,XX male syndrome is a rare disorder that usually causes infertility. This study was established to identify the genetic causes of this condition in a series of 46,XX males through the combined application of cytogenetic and molecular genetic techniques.

Case presentation

We identified eight azoospermic 46,XX males who underwent infertility-related consultations at our center. They all presented normal male phenotypes. In seven of the eight 46,XX males (87.5%), translocation of the SRY gene to the terminal short arm of the X chromosome was clearly involved in their condition, which illustrated that this translocation is the main mechanism of 46,XX sex reversal, in line with previous reports. However, one patient presented a homozygous DAX1 mutation (c.498G > A, p.R166R), which was not previously reported in SRY-negative XX males.

Conclusions

We proposed that this synonymous DAX1 mutation in case 8 might not be associated with the activation of the male sex-determining pathway, and the male phenotype in this case might be regulated by some unidentified genetic or environmental factors. Hence, the detection of genetic variations associated with sex reversal in critical sex-determining genes should be recommended for SRY-negative XX males. Only after comprehensive cytogenetic and molecular genetic analyses can genetic counseling be offered to 46,XX males.

A clinical algorithm to diagnose differences of sex development

The diagnosis and management of children born with ambiguous genitalia is challenging for clinicians. Such differences of sex development (DSDs) are congenital conditions in which chromosomal, gonadal, or anatomical sex is atypical. The aetiology of DSDs is very heterogenous and a precise diagnosis is essential for management of genetic, endocrine, surgical, reproductive, and psychosocial issues. In this Review, we outline a step-by-step approach, compiled in a diagnostic algorithm, for the clinical assessment and molecular diagnosis of a patient with ambiguity of the external genitalia on initial presentation. We appraise established and emerging technologies and their effect on diagnosis, and discuss current controversies.

Translating genomics to the clinical diagnosis of disorders/differences of sex development

The medical and psychosocial challenges faced by patients living with Disorders/Differences of Sex Development (DSD) and their families can be alleviated by a rapid and accurate diagnostic process. Clinical diagnosis of DSD is limited by a lack of standardization of anatomical and endocrine phenotyping and genetic testing, as well as poor genotype/phenotype correlation. Historically, DSD genes have been identified through positional cloning of disease-associated variants segregating in families and validation of candidates in animal and in vitro modeling of variant pathogenicity. Owing to the complexity of conditions grouped under DSD, genome-wide scanning methods are better suited for identifying disease causing gene variant(s) and providing a clinical diagnosis. Here, we review a number of established genomic tools (karyotyping, chromosomal microarrays and exome sequencing) used in clinic for DSD diagnosis, as well as emerging genomic technologies such as whole-genome (short-read) sequencing, long-read sequencing, and optical mapping used for novel DSD gene discovery. These, together with gene expression and epigenetic studies can potentiate the clinical diagnosis of DSD diagnostic rates and enhance the outcomes for patients and families.

A Follow-Up from Infancy to Puberty in a Japanese Male with SRY-Negative 46,XX Testicular Disorder of Sex Development Carrying a p.Arg92Trp Mutation in NR5A1

SRY-negative 46,XX testicular disorders of sex development (DSD) are very rare conditions. Recently, we identified a novel heterozygous NR5A1 mutation, p.Arg92Trp (c.274C>T, p.R92W), in 2 unrelated cases of 46,XX testicular/ovotesticular DSD. We report the clinical course from infancy to puberty in a Japanese male with SRY-negative 46,XX testicular DSD, carrying this p.Arg92Trp mutation in NR5A1. The patient naturally acquired the development of a penis and pubic hair during puberty. However, hypergonadotropic hypogonadism subsequently developed. More clinical cases will be needed to fully understand the effects of the p.Arg92Trp mutation on the ability to maintain testosterone secretion in 46,XX testicular DSD.

Genetic evaluation of disorders of sex development: current practice and novel gene discovery

PURPOSE OF REVIEW

As the pace of genetic discovery accelerates, genetic sequencing is increasingly applied to rare disease such as DSD (differences or disorders of sex development,) which has led to an increase in the number of novel variant-containing candidate genes identified. In this review, we will discuss several candidate genes which have recently been proposed as causative of DSD, as well as novel work in understanding gene regulation in the mouse gonad that may have implications for the DSD phenotype in humans.

RECENT FINDINGS

We performed a comprehensive search of PubMed through August 2018 to identify relevant peer-reviewed publications from 2017 to 2018 on DSD genetics.

SUMMARY

Seminal work has identified a critical gonadal enhancer of Sox9 in a mouse model. This enhancer is located in a region which had previously been implicated in both XX and XY DSD, though the specific enhancer and its role in Sox9 gene expression had not been defined. Novel candidate genes in XY gonadal dysgenesis (SOX8, ESR2) and XX ovotesticular DSD (NR2F2) have been described.

Natural sex change in fish

Sexual fate can no longer be considered an irreversible deterministic process that once established during early embryonic development, plays out unchanged across an organism's life. Rather, it appears to be a dynamic process, with sexual phenotype determined through an ongoing battle for supremacy between antagonistic male and female developmental pathways. That sexual fate is not final and is actively regulated via the suppression or activation of opposing genetic networks creates the potential for flexibility in sexual phenotype in adulthood. Such flexibility is seen in many fish, where sex change is a usual and adaptive part of the life cycle. Many fish are sequential hermaphrodites, beginning life as one sex and changing sometime later to the other. Sequential hermaphrodites include species capable of female-to-male (protogynous), male-to-female (protandrous), or bidirectional (serial) sex change. These natural forms of sex change involve coordinated transformations across multiple biological systems, including behavioral, anatomical, neuroendocrine and molecular axes. Here we review the biological processes underlying this amazing transformation, focusing particularly on the molecular aspects, where new genomic technologies are beginning to help us understand how sex change is initiated and regulated at the molecular level.

Mutational and functional studies on NR5A1 gene in 46,XY disorders of sex development: identification of six novel loss of function mutations

OBJECTIVE

To study the functional properties of six novel missense mutations of the NR5A1 gene encoding the steroidogenic factor 1 (SF-1) identified in six patients with 46,XY disorders of sex development (DSD) and to describe their relative phenotype-genotype relationship.

DESIGN

Genetic and functional studies.

SETTING

University department.

PATIENT(S)

Six 46,XY DSD patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Sanger sequencing and multiplex ligation-dependent probe amplification analysis to identify the mutations or deletions/duplications of the NR5A1 gene. Functional studies by transactivation assays to predict the impact of mutations on molecular function.

RESULT(S)

NR5A1 exons sequencing identified in six 46,XY DSD patients six novel mutations: p.T40R, p.T47C, p.G328W, p.A351E, p.R427W, and p.Q460R. Five missense variants were heterozygous, and one was homozygous (p.R427W). Functional analysis revealed a significant loss of DNA-binding and transactivation ability for all variants, except for p.Q460R, which showed a modest reduced activity compared with that of the wild-type protein. Phenotypes associated with these mutations varied from males with spontaneous puberty, substantial T production, and possible fertility, to females with and without müllerian structures and primary amenorrhea.

CONCLUSION(S)

We describe six novel mutations in NR5A1 gene and showed that they might affect protein structure, therefore compromising seriously the SF-1 role in regulating gonadal development. Clinically, we suggest that NR5A1 analysis should be performed whenever atypical sex organs are evidenced or there is an abnormal sexual development, to have proper diagnosis and better management of patients.

Spontaneous virilization around puberty in NR5A1-related 46,XY sex reversal: additional case and a literature review

A heterozygous NR5A1 mutation is one of the most frequent causes of 46,XY DSD (disorders of sex development). We here reported a NR5A1-related 46,XY DSD patient, who first received endocrinological attention at 10 years of age for clitoromegaly. The patient had been reared as a girl, and no signs of virilization had been detected before. On examination, her clitoris was 35 mm long and 10 mm wide, with Tanner 3° pubic hair. Urogenital sinus and labial fusion was absent, while her uterus was found to be severely hypoplastic. Her basal testosterone level was 94.8 ng/dL, suggesting the presence of functioning Leydig cells. Gonadal histology revealed bilateral dysplastic testes consisting of mostly Sertoli cell-only tubules and Leydig cell hyperplasia. Novel heterozygous Arg313Leu substitution in NR5A1 was identified in the patient. Literature search confirmed twelve other cases of this scenario, namely, severe under-virilization in utero followed by spontaneous virilization around puberty in NR5A1-related 46,XY DSD. Of interest, Leydig cell hyperplasia was documented in 6 out of 9 patients for whom testicular histology was available. To keep in mind about the possible restoration of Leydig cell function around puberty, even in patients without discernible in utero androgen effect, may be of clinical significance, because it will give a great impact on the judgement about sex assignment.

NR5A1 gene variants repress the ovarian-specific WNT signaling pathway in 46,XX disorders of sex development patients

Several recent reports have described a missense variant in the gene NR5A1 (c.274C>T; p.Arg92Trp) in a significant number of 46,XX ovotesticular or testicular disorders of sex development (DSDs) cases. The affected residue falls within the DNA‐binding domain of the NR5A1 protein, however the exact mechanism by which it causes testicular development in 46,XX individuals remains unclear. We have screened a cohort of 26 patients with 46,XX (ovo)testicular DSD and identified three unrelated individuals with this NR5A1 variant (p.Arg92Trp), as well as one patient with a novel NR5A1 variant (c.779C>T; p.Ala260Val). We examined the functional effect of these changes, finding that while protein levels and localization were unaffected, variant NR5A1 proteins repress the WNT signaling pathway and have less ability to upregulate the anti‐testis gene NR0B1. These findings highlight how NR5A1 variants impact ovarian differentiation across multiple pathways, resulting in a switch from ovarian to testis development in genetic females.

Phenotype and Molecular Characterizations of 30 Children From China With NR5A1 Mutations

Background: Patients harboring NR5A1 mutations have a wide spectrum of phenotypes.

Objective: To investigate the phenotype of patients with NR5A1 gene mutations from a 30 Chinese patient cohort.

Methods: We reported the clinical features of children with NR5A1 gene mutations and compared them between two groups of patients with social genders of male (boys group) and female (girls group).

Results: Thirty patients with NR5A1 mutations ranging from 2 months to 17 years of age were studied. There were 11 boys and 19 girls who were identified when they visited the hospital. The patients were verified as having testes without a uterus and ovaries by B-mode ultrasound. There was no difference between boys and girls in terms of the Prader stage (p = 0.086), but the position of the testes was higher in girls than in boys (p = 0.013). The patients’ average height is −0.43 SDS according to the normal boys’ height with SDS (while their average target height was 0.07 SDS). However, there was no such difference between boys and girls (p > 0.05). Although the basal LH and post-hCG testosterone (T) levels were not different (p > 0.05), but the basal FSH level, LH/FSH ratio, and INHB level were decreased in girls (p = 0.002; p = 0.001; p = 0.006). All of the mothers of the patients reported to have normal pregnancies. We found 24 patients (80%) with de novo mutations in the NR5A1 gene; 5 patients had inherited mutations from their mothers, and one inherited from the father. Only the mothers of patients 16 and 18 showed premature ovarian failure at the time of reporting. Among 26 disease associated mutations, 14 novel mutations that have been reported the first time and p.R87C is the most common Among the other 12 had had been reported,the p.R313C is the most common.

Conclusion: Patients with 46, XY NR5A1 mutations presented a wide spectrum of external genitalia characteristics and severe Sertoli cell impairment. The p.R87C and p.R313C mutations appeared to be common (10%) in this group, and 14 new mutations were identified, improving our understanding the genotype phenotype correlations.

Early-Onset Complete Ovarian Failure and Lack of Puberty in a Woman With Mutated Estrogen Receptor β (ESR2)

CONTEXT

Estrogen resistance due to mutations in the estrogen receptor α gene (ESR1) has been described in men and women and is characterized by osteoporosis, delayed bone age and continuous growth in adulthood, and delayed puberty and multiple ovarian cysts in women. Although mutations in the estrogen receptor β gene ESR2 were found in 46, XY patients with differences of sex development, no genetic variants of ESR2 were linked to gonadal defects in women.

SETTINGS AND PATIENT

Here we describe a 16-year-old female patient who came to our tertiary care hospital with complete lack of estrogen action, as demonstrated by absent breast development, primary amenorrhea, and osteoporosis, resembling patients with ESR1 mutation. However, her gonads were clearly abnormal (streak), a finding not observed in ESR1-deficient patients.

DESIGN

To gain insights into the molecular consequences of the ESR2 defect, whole exome sequencing and extensive functional transactivation studies in ovarian, bone, and breast cells were conducted, with or without the natural activator of estrogen receptors, 17β-estradiol.

RESULTS

We identified a loss-of-function heterozygous mutation of a highly conserved residue in ESR2 that disrupts estradiol-dependent signaling and has a dominant negative effect, most likely due to failure to interact with its coactivator, nuclear coactivator 1.

CONCLUSIONS

This is a report of a loss-of-function mutation in the estrogen receptor β in a young woman with complete ovarian failure, suggesting that ESR2 is necessary for human ovarian determination and/or maintenance and that ESR1 is not sufficient to sustain ovarian function in humans.

GENETICS IN ENDOCRINOLOGY: Approaches to molecular genetic diagnosis in the management of differences/disorders of sex development (DSD): position paper of EU COST Action BM 1303 ‘DSDnet’

The differential diagnosis of differences or disorders of sex development (DSD) belongs to the most complex fields in medicine. It requires a multidisciplinary team conducting a synoptic and complementary approach consisting of thorough clinical, hormonal and genetic workups. This position paper of EU COST (European Cooperation in Science and Technology) Action BM1303 ‘DSDnet’ was written by leading experts in the field and focuses on current best practice in genetic diagnosis in DSD patients. Ascertainment of the karyotpye defines one of the three major diagnostic DSD subclasses and is therefore the mandatory initial step. Subsequently, further analyses comprise molecular studies of monogenic DSD causes or analysis of copy number variations (CNV) or both. Panels of candidate genes provide rapid and reliable results. Whole exome and genome sequencing (WES and WGS) represent valuable methodological developments that are currently in the transition from basic science to clinical routine service in the field of DSD. However, in addition to covering known DSD candidate genes, WES and WGS help to identify novel genetic causes for DSD. Diagnostic interpretation must be performed with utmost caution and needs careful scientific validation in each DSD case.

Non-Syndromic 46,XY Disorders of Sex Development

Non-syndromic 46,XY DSD (disorders of sex development) represent a phenotypically diversiform group of disorders. We focus on the association between gene variants and the most frequent types of non-syndromic 46,XY DSD, options of molecular genetic testing which has surely taken its place in diagnostics of DSD in the past couple of years. We emphasize the need of molecular genetic testing in individuals with non-syndromic 46,XY DSD in Slovak Republic.