The spectrum of phenotypes associated with mutations in steroidogenic factor 1 (SF-1, NR5A1, Ad4BP) includes severe penoscrotal hypospadias in 46,XY males without adrenal insufficiency

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.

NR5A1-related 46,XY partial gonadal dysgenesis: A case report and literature review

RATIONALE

Disorders/differences of sex development (DSD) include a diverse group of congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is discordant. It involves several variant genes, and one of them is NR5A1. NR5A1 encodes a signal transduction regulator in the hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal pathway, and pathogenic mutation in this gene is a cause of 46,XY DSD.

PATIENT CONCERNS

A 12-year-old individual raised as a girl was admitted to the hospital due to hirsutism and a deep voice that began at 11 years old. The individual exhibited testicular hypoplasia, clitoral hypertrophy, and female external genitalia.

DIAGNOSES

The patient was diagnosed 46,XY partial gonadal dysgenesis. The cytogenetics revealed a 46,XY karyotype and DNA sequencing shown a variant in NR5A1. Pelvic magnetic resonance imaging showed absence of uterus and ovaries. The abdominopelvic ultrasound revealed bilateral testicle in bilateral groin. Pathology confirmed testes dysgenesis.

INTERVENTIONS

The patient underwent bilateral orchiectomy at age 12 years and was given a feminizing hormonal treatment of 0.5 mg/day of estradiol valerate tablets.

OUTCOMES

The patient recovered well after surgery and hormonal treatment and had a regression in hirsutism and clitoromegaly.

LESSONS

46,XY DSD is a rare disease that the development of chromosomal, gonadal, or anatomical sex is discordant, when diagnosed 46,XY DSD, the identification of an NR5A1 variant should be considered.

An extra-genital cell population contributes to urethra closure during mouse penis development

Hypospadias, or incomplete closure of the urethra along the penis, is the second most common birth defect in the United States. We discovered a population of extra-genital mesenchymal cells that are essential for proper penile urethra closure in mouse embryos. This extra-genital population first appeared in the mesenchyme posterior to the hindlimb of the fetus after the onset of penis formation. These extra-genital cells, which transiently express a lineage marker Nr5a1, migrated centrally and colonized the penis bilateral to the urethra epithelium. Removal of the Nr5a1+ extra-genital cells, using a cell-type specific ablation model, resulted in severe hypospadias. The absence of extra-genital cells had the most significant impacts on another mesenchymal cells, the peri-urethra that were immediately adjacent to the Nr5a1+ extra-genital cells. Single cell mRNA sequencing revealed that the extra-genital cells extensively interact with the peri-urethra, particularly through Neuregulin 1, an epidermal Growth Factor (EGF) ligand. Disruption of Neuregulin 1 signaling in the ex-vivo slice culture system led to failure of urethra closure, recapitulating the phenotypes of extra-genital cell ablation. These results demonstrate that the Nr5a1+ extra-genital mesenchymal cells from outside of the fetal penis are indispensable for urethra closure through their interaction with the peri-urethra mesenchymal cells. This discovery provides a new entry point to understand the biology of penis formation and potential causes of hypospadias in humans.

Whole-exome sequencing study of hypospadias

Hypospadias results from the impaired urethral development, which is influenced by androgens, but its genetic etiology is still unknown. Through whole exome sequencing analysis, we identified NR5A1, SRD5A2, and AR as mutational hotspots in the etiology of severe hypospadias, as these genes are related to androgen signaling. Additionally, rare damaging variants in cilia-related outer dynein arm heavy chain (ODNAH) genes (DNAH5, DNAH8, DNAH9, DNAH11, and DNAH17) (p = 8.5 × 10-47) were significantly enriched in hypospadias cases. The Dnah8 KO mice exhibited significantly decreased testosterone levels, which had an impact on urethral development and disrupted steroid biosynthesis. Combined with trios data, transcriptomic, and phenotypical and proteomic characterization of a mouse model, our work links ciliary genes with hypospadias. Overall, a panel of ODNAH genes with rare damaging variants was identified in 24% of hypospadias patients, providing significant insights into the underlying pathogenesis of hypospadias as well as genetic counseling.

Comprehensive multidisciplinary phenotyping of patients with hypospadias. A pilot study

INTRODUCTION

Hypospadias is an abnormal formation of the urethra, ventral skin, and corporal bodies. Location of the urethral meatus has historically been the phenotypic landmark that defines hypospadias. Nonetheless, classifications following location of the urethral meatus fail to consistently predict outcomes and have no correlation with the genotype. Description of the urethral plate is very subjective and difficult to reproduce. We hypothesize that the use of digital pixel cluster analysis and correlation to histological analysis can provide a novel method to describe the phenotype of patients with hypospadias.

METHODS

A standardized hypospadias phenotyping protocol was developed. 1. Digital images of the anomaly, 2. Anthropometric assessment of penile dimensions (penile length, urethral plate length and width, glans width, ventral curvature), 3. Classification using the GMS score, 4. Tissue sampling (foreskin, glans, urethral plate, periurethral ventral skin) and H&E analysis by a blinded pathologist. A k-means colorimetric pixel cluster analysis was performed following the same anatomical landmark distribution as the histology samples. Analysis was performed using MATLAB v R2021b 9.11.0.1769968.

RESULTS

A total of 24 patients prospectively enrolled with a standard protocol. Mean age at surgery was 16.25 months Urethral meatus was distal shaft in 7 patients, 8 coronal, 4 glanular, 3 midshaft, 2 penoscrotal. Average GMS score was 7.14 (±1.58). Average glans size was 15.71 mm (±2.33) and urethral plate width 5.57 mm (±2.06). Eleven patients underwent Thiersch-Duplay repair, 7 TIP, 5 MAGPI, and 1 a first stage preputial flap. Mean follow-up was 14.25 months ( ± 3.7 months). Two (8.3%) postoperative complications (1 urethrocutaneous fistula and 1 ventral skin wound dehiscence) were reported in the study period. Eleven (52.3%) patients with histological analysis had an abnormal pathology report. Of those, 6 (54%) had reported abnormal lymphocyte infiltration interpreted as chronic inflammation at the urethral plate. The second most common finding was hyperkeratosis visualized in the urethral plate in 4 (36.3%) and one with reported fibrosis in the urethral plate. K-means pixel analysis demonstrated a k1 mean of 64.2 for reported urethral plate inflammation vs 53.1 for non-reported urethral plate inflammation (p = 0.002) CONCLUSIONS: Current phenotyping of hypospadias using only anthropometric variables can be expanded including histological and pixel analysis correlation. Pixel clustering has a potential for a priori prediction of urethral plate quality beyond the current subjective assessment. A larger cohort will allow identification of possible predictive associations that might impact intraoperative decision-making and surgical outcomes.

Deep learning based automated quantification of urethral plate characteristics using the plate objective scoring tool (POST)

INTRODUCTION

The plate objective scoring tool (POST) was recently introduced as a reproducible and precise approach to quantifying urethral plate (UP) characteristics and guide to selecting particular surgical techniques. However, defining the landmarks mandatory for the POST score from captured images can potentially leads to variability. Although artificial intelligence (AI) is yet to be wholly accepted and explored in hypospadiology, it has certainly brought new possibilities to light.

OBJECTIVES

To explore the capacity of deep learning algorithm to further streamline and optimize UP characteristics appraisal on 2D images using the POST, aiming to increase the objectivity and reproducibility of UP appraisal in hypospadias repair.

METHODS

The five key POST landmarks were marked by specialists in a 691-image dataset of prepubertal boys undergoing primary hypospadias repair. This dataset was then used to develop and validate a deep learning-based landmark detection model. The proposed framework begins with glans localization and detection, where the input image is cropped using the predicted bounding box. Next, a deep convolutional neural network (CNN) architecture is used to predict the coordinates of the five POST landmarks. These predicted landmarks are then used to assess UP characteristics in distal hypospadias.

RESULTS

The proposed model accurately localized the glans area, with a mean average precision (mAP) of 99.5% and an overall sensitivity of 99.1%. A normalized mean error (NME) of 0.07152 was achieved in predicting the coordinates of the landmarks, with a mean squared error (MSE) of 0.001 and a 2.5% failure rate at a threshold of 0.2 NME.

DISCUSSION

Our results support the possibility of further standardizing UP assessment from captured hypospadias images, and the use of machine learning algorithms and image recognition shows that these novel artificial intelligence technologies are useful for scoring hypospadias. External validation can provide valuable information on the generalizability and reliability of deep learning algorithms, which can aid in assessments, decision-making and predictions for surgical outcomes.

CONCLUSIONS

This deep learning application shows robustness and high precision in using POST to appraise UP characteristics. Further assessment using international multi-centre image-based databases is ongoing.

Phenotype and genetic characteristics in 20 Chinese patients with 46,XY disorders of sex development

PURPOSE

46,XY disorders of sex development (DSD) is the most complicated and common type of DSD. To date, more than 30 genes have been identified associated with 46,XY DSD. However, the mutation spectrum of 46,XY DSD is incomplete owing to the high genetic and clinical heterogeneity. This study aims to provide clinical and mutational characteristics of 18 Chinese patients with 46,XY DSD.

METHODS

A total of 20 unrelated individuals with 46,XY DSD were recruited. Whole-exome sequencing (WES) or custom-panel sequencing combined Sanger sequencing were performed to detect the pathogenic mutations. The pathogenicity of the variant was assessed according to the American College of Medical Genetics and Genomics (ACMG) guidance and technical standards recommended by the ACMG and the Clinical Genome Resource (ClinGen).

RESULTS

Six patients harbored NR5A1 mutations; two patients harbored NR0B1 mutations; six patients harbored SRD5A2 mutations; six patients harbored AR mutations. Six novel genetic variants were identified involved in three genes (NR5A1, NR0B1, and AR).

CONCLUSION

We determined the genetic etiology for all enrolled patients. Our study expanded the mutation spectrum of 46,XY DSD and provided diagnostic evidence for patients with the same mutation in the future.

Recurrent ventral curvature after corporoplasty with tunica vaginalis flap

INTRODUCTION AND OBJECTIVE

Optimal means to correct ventral curvature (VC) is debated. Our preferred technique for curvature greater than 45° is corporoplasty using tunica vaginalis flap (TVF). We describe our complications with TVF for ventral lengthening.

METHODS

Forty-four boys who underwent ventral lengthening with a corporoplasty with TVF were identified in a prospective database for proximal hypospadias repair by a single surgeon from 2008 to 2021. Corporotomy was performed by incising the tunica albuginea of the corpora cavernosa transversely at the point of maximum curvature. Harvested TVF was tailored to the size of the corporotomy and anastomosed to the edges of the tunica albuginea and on laid to the corporal defect with the mesothelial side of the TVF abutting the erectile tissue.

RESULTS

Median age at surgery was 1.0 years (IQR 0.72-1.82). Median follow-up time was 4.9 years (IQR 2.6-8.0). Thirteen patients (27%) were older than 10 years of age at last follow up (median 13.3, range 10-20). Twenty-two boys (50%) received preoperative testosterone. The most common location of the meatus after degloving was penoscrotal (41%). Median VC after degloving was 90° (IQR 80-100). The urethral plate was transected in 43/44 (98%) of boys, improving median VC to 60° (IQR 40-60). After corporotomy, the median longitudinal distracted distance was 15 mm (IQR 12-17). Urethral reconstruction was most commonly achieved with the transverse island preputial flap technique or its modifications (39/44; 89%). Erections were reported in 42 boys (95%). None developed corporal diverticula, and two patients (4.5%) had ascended testis associated with TVF harvest. Seven percent of boys had recurrent ventral curvature (RVC; 3/44). Median RVC was 30° (IQR 30-45). One patient had RVC at the penoscrotal junction (not at site of prior corporoplasty) identified 11 years post operatively at age 15, and underwent dorsal plication. The other 2 patients were diagnosed less than 1 year post operatively. Both patients received testosterone due to small glans size, had double-face tubularized transverse island preputial flap as urethral and ventral skin coverage, and had endocrine and genetic consultation. Both had scarring of the preputial flap and of the corporoplasty. Scar excision and superficial transverse incisions on the tunica albuginea corrected RVC.

CONCLUSIONS

The five-year outcome of ventral penile lengthening using TVF for corporoplasty is favorable with 7% of boys with RVC, and 4.5% with ascended testes associated with TVF harvest. None developed corporal diverticula.

The Use of Genetics for Reaching a Diagnosis in XY DSD

Reaching a firm diagnosis is vital for the long-term management of a patient with a difference or disorder of sex development (DSD). This is especially the case in XY DSD where the diagnostic yield is particularly low. Molecular genetic technology is playing an increasingly important role in the diagnostic process, and it is highly likely that it will be used more often at an earlier stage in the diagnostic process. In many cases of DSD, the clinical utility of molecular genetics is unequivocally clear, but in many other cases there is a need for careful exploration of the benefit of genetic diagnosis through long-term monitoring of these cases. Furthermore, the incorporation of molecular genetics into the diagnostic process requires a careful appreciation of the strengths and weaknesses of the evolving technology, and the interpretation of the results requires a clear understanding of the wide range of conditions that are associated with DSD.

SRY and NR5A1 gene mutation in Algerian children and adolescents with DSD and testicular dysgenesis

Background

In humans, sex determination and differentiation is genetically controlled. Disorders of sex development (DSD) result in anomalies of the development of the external and internal genitalia. Variants in transcription factors such as SRY, NR5A1 and SOX9, can cause changes in gonadal development often associated with ambiguity of the external genitalia.

Objectives

This study has been conducted to determine the frequency, types and associated genetic alterations in patients with DSD in the Algerian population.

Methods

Thirty patients were included. Based on their clinical presentation, thirteen patients presented with ambiguous external genitalia, thirteen patients presented with hypospadias and four patients presented with bilateral undescended testes. Karyotype analysis was performed on peripheral blood lymphocytes using standard R-banding. DNA was isolated from blood leukocytes for PCR reaction and mutational analysis of SRY and NR5A1 was done by direct sequencing.

Results

Most patients with ambiguous genitalia had a 46,XY karyotype. One patient had a deletion of SRY, otherwise no point mutations in SRY or NR5A1 genes were identified. However, a single NR5A1 polymorphism (p.Gly146Ala) in patient with 46,XX DSD has been detected.

Conclusions

The absence of mutations in these genes suggests that there are others genes playing an important role in sex development and differentiation.

NR5A1 c.991-1G > C splice-site variant causes familial 46,XY partial gonadal dysgenesis with incomplete penetrance

OBJECTIVE

The study aimed to identify the genetic basis of partial gonadal dysgenesis (PGD) in a non-consanguineous family from Estonia.

PATIENTS

Cousins P (proband) 1 (12 years; 46,XY) and P2 (18 years; 46,XY) presented bilateral cryptorchidism, severe penoscrotal hypospadias, low bitesticular volume and azoospermia in P2. Their distant relative, P3 (30 years; 46,XY), presented bilateral cryptorchidism and cryptozoospermia.

DESIGN

Exome sequencing was targeted to P1-P3 and five unaffected family members.

RESULTS

P1-P2 were identified as heterozygous carriers of NR5A1 c.991-1G > C. NR5A1 encodes the steroidogenic factor-1 essential in gonadal development and specifically expressed in adrenal, spleen, pituitary and testes. Together with a previous PGD case from Belgium (Robevska et al 2018), c.991-1G > C represents the first recurrent NR5A1 splice-site mutation identified in patients. The majority of previous reports on NR5A1 mutation carriers have not included phenotype-genotype data of the family members. Segregation analysis across three generations showed incomplete penetrance (<50%) and phenotypic variability among the carriers of NR5A1 c.991-1G > C. The variant pathogenicity was possibly modulated by rare heterozygous variants inherited from the other parent, OTX2 p.P134R (P1) or PROP1 c.301_302delAG (P2). For P3, the pedigree structure supported a distinct genetic cause. He carries a previously undescribed likely pathogenic variant SOS1 p.Y136H. SOS1, critical in Ras/MAPK signalling and foetal development, is a strong novel candidate gene for cryptorchidism.

CONCLUSIONS

Detailed genetic profiling facilitates counselling and clinical management of the probands, and supports unaffected mutation carriers in the family for their reproductive decision making.

Etiology of Hypospadias: A Comparative Review of Genetic Factors and Developmental Processes Between Human and Animal Models

Hypospadias is a congenital anomaly of the penis with an occurrence of approximately 1 in 200 boys, but the etiology of the majority of hypospadias has remained unknown. Numerous genes have been reported as having variants in hypospadias patients, and many studies on genetic deletion of key genes in mouse genital development have also been published. Until now, no comparative analysis in the genes related literature has been reported. The basic knowledge of penile development and hypospadias is mainly obtained from animal model studies. Understanding of the differences and similarities between human and animal models is crucial for studies of hypospadias. In this review, mutations and polymorphisms of hypospadias-related genes have been compared between humans and mice, and differential genotype–phenotype relationships of certain genes between humans and mice have been discussed using the data available in PubMed and MGI online databases, and our analysis only revealed mutations in seven out of 43 human hypospadias related genes which have been reported to show similar phenotypes in mutant mice. The differences and similarities in the processes of penile development and hypospadias malformation among human and commonly used animal models suggest that the guinea pig may be a good model to study the mechanism of human penile development and etiology of hypospadias.

[Clinical and molecular characteristics of patients with 46,XY DSD due to NR5A1 gene mutations]

Steroidogenic factor 1 (SF1, NR5A1) is a nuclear receptor that regulates multiple genes involved in adrenal and gonadal development, steroidogenesis, and the reproductive axis. Human mutations in SF1 were initially found in patients with severe gonadal dysgenesis and primary adrenal failure. However, more recent case reports have suggested that heterozygous mutations in SF1 may also be found in patients with 46,XY partial gonadal dysgenesis and underandrogenization but normal adrenal function. We have analyzed the gene encoding SF1 (NR5A1) in a cohort of 310 Russian patients with 46,XY disorders of sex development (DSD). Heterozygous SF1 variants were found in 36 out of 310 (11.6%) of cases, among them 15 were not previously described. We have not found any phenotype-genotype correlations and any clinical and laboratory markers that would allow to suspect this type of before conducting molecular genetic analysis.

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."

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.

[Di (2-ethylhexyl) phthalate-induced hypospadias in SD rats is related with Mafb expression: a transcriptome profiling-based study]

OBJECTIVE

To investigate the transcriptome profile of genital tubercles (GTs) in male SD rats and explore the mechanism of hypospadias induced by Di (2-ethylhexyl) phthalate (DEHP).

METHODS

Forty time-pregnant SD rats were randomly divided into 4 equal groups, namely GD16 group and GD19 group (in which the male GTs were collected on gestation day[GD]16 and GD19 for RNA-seq, respectively), control group and DEHP exposure group (with administration of oil and 750 mg/kg DEHP by gavage from GD12 to GD19, respectively).In the control and DEHP exposure groups, the GTs were collected from the male fetuses on GD19.5, and scanning electron microscopy and HE staining were used to observe the morphological changes.The differentially expressed genes (DEGs) in the GTs were screened using lllumina HiSeq 2000 followed by GO and KEGG enrichment analyses to characterize the transcriptome profile.Immunofluorescence assay was performed to verify the DEGs (Mafb) identified by RNA-seq results.Immunofluorescence assay and Western blotting were used to examine the expression levels of Mafb in the penile tissue.

RESULTS

A total of 1360 DEGs were detected in the GTs between GD16 group and GD19 group by RNA-seq.Among these genes, 797 were up-regulated and 563 were down-regulated.These DEGs were mainly enriched in the cell adhesion plaque signaling pathway, axon guidance signaling pathway, and extracellular matrix receptor signaling pathway.Compared with that in GD16 group, Mafb was significantly up-regulated in GD19 group, which was consistent with the sequencing results.Mafb and β-catenin were significantly down-regulated in DEHP-exposed group compared with the control group (P &lt; 0.01).

CONCLUSIONS

Mafb expression increases progressively with the development of GTs in male SD rats.DEHP exposure causes significant down-regulation of Mafb and β-catenin, suggesting that β-catenin signaling pathway that affects Mafb is related to DEHP-induced hypospadias in SD rats.

The Orphan Nuclear Receptors Steroidogenic Factor-1 and Liver Receptor Homolog-1: Structure, Regulation, and Essential Roles in Mammalian Reproduction

Nuclear receptors are intracellular proteins that act as transcription factors. Proteins with classic nuclear receptor domain structure lacking identified signaling ligands are designated orphan nuclear receptors. Two of these, steroidogenic factor-1 (NR5A1, also known as SF-1) and liver receptor homolog-1 (NR5A2, also known as LRH-1), bind to the same DNA sequences, with different and nonoverlapping effects on targets. Endogenous regulation of both is achieved predominantly by cofactor interactions. SF-1 is expressed primarily in steroidogenic tissues, LRH-1 in tissues of endodermal origin and the gonads. Both receptors modulate cholesterol homeostasis, steroidogenesis, tissue-specific cell proliferation, and stem cell pluripotency. LRH-1 is essential for development beyond gastrulation and SF-1 for genesis of the adrenal, sexual differentiation, and Leydig cell function. Ovary-specific depletion of SF-1 disrupts follicle development, while LRH-1 depletion prevents ovulation, cumulus expansion, and luteinization. Uterine depletion of LRH-1 compromises decidualization and pregnancy. In humans, SF-1 is present in endometriotic tissue, where it regulates estrogen synthesis. SF-1 is underexpressed in ovarian cancer cells and overexpressed in Leydig cell tumors. In breast cancer cells, proliferation, migration and invasion, and chemotherapy resistance are regulated by LRH-1. In conclusion, the NR5A orphan nuclear receptors are nonredundant factors that are crucial regulators of a panoply of biological processes, across multiple reproductive tissues.

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.

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.

Genetic testing of XY newborns with a suspected disorder of sex development

PURPOSE OF REVIEW

The current review focuses on the neonatal presentation of disorders of sex development, summarize the current approach to the evaluation of newborns and describes recent advances in understanding of underlying genetic aetiology of these conditions.

RECENT FINDINGS

Several possible candidate genes as well as other adverse environmental factors have been described as contributing to several clinical subgroups of 46,XY DSDs. Moreover, registry-based studies showed that infants with suspected DSD may have extragenital anomalies and in 46,XY cases, being small for gestational age (SGA), cardiac and neurological malformations are the commonest concomitant conditions.

SUMMARY

Considering that children and adults with DSD may be at risk of several comorbidities a clear aetiological diagnosis will guide further management. To date, a firm diagnosis is not reached in over half of the cases of 46,XY DSD. Whilst it is likely that improved diagnostic resources will bridge this gap in the future, the next challenge to the clinical community will be to show that such advances will result in an improvement in clinical care.

Functional characterization of novel NR5A1 variants reveals multiple complex roles in disorders of sex development

Variants in the NR5A1 gene encoding SF1 have been described in a diverse spectrum of disorders of sex development (DSD). Recently, we reported the use of a targeted gene panel for DSD where we identified 15 individuals with a variant in NR5A1, nine of which are novel. Here, we examine the functional effect of these changes in relation to the patient phenotype. All novel variants tested had reduced trans‐activational activity, while several had altered protein level, localization, or conformation. In addition, we found evidence of new roles for SF1 protein domains including a region within the ligand binding domain that appears to contribute to SF1 regulation of Müllerian development. There was little correlation between the severity of the phenotype and the nature of the NR5A1 variant. We report two familial cases of NR5A1 deficiency with evidence of variable expressivity; we also report on individuals with oligogenic inheritance. Finally, we found that the nature of the NR5A1 variant does not inform patient outcomes (including pubertal androgenization and malignancy risk). This study adds nine novel pathogenic NR5A1 variants to the pool of diagnostic variants. It highlights a greater need for understanding the complexity of SF1 function and the additional factors that contribute.

Genetic Screening of Iranian Patients with 46,XY Disorders of Sex Development

BACKGROUND

Disorders of sex development (DSDs) belong to uncommon pathologies and result from abnormalities during gonadal determination and differentiation. Various gene mutations involved in gonadal determination and differentiation have been associated with gonadal dysgenesis. Despite advances in exploration of genes and mechanisms involved in sex disorders, most children with severe 46,XY DSDs have no definitive etiological diagnoses; therefore, the possibility that other genes or loci might play important roles in these disorders needs to be explored.

METHODS

Patients (37) clinically suspicious for 46,XY gonadal dysgenesis (46,XY GD) of unknown etiology were studied. SRY, encoding the sex-determining region Y protein, NR5A1, encoding a transcription factor called steroidogenic factor 1, and DHH, encoding the desert hedgehog protein, were directly sequenced. Multiplex ligation-dependent probe amplification (MLPA) was used to detect deletions in NR0B1, encoding the DAX1 protein, and WNT4, encoding the WNT4 protein, and real-time PCR (qPCR) confirmed the MLPA data. Other potential loci have been investigated in the complete genome using Array-Comparative Genomic Hybridization, (Array CGH).

RESULTS

The SRY deletion was found in five patients. One each of previously described NR5A1, DHH, and AR (androgen receptor) allelic variants were identified. A pathogenic c.2522G>A AR mutation was found in two affected brothers. A heterozygous partial deletion was found in NR5A1 and heterozygous partial duplications were found in WNT4. These deletions and duplications (del/dup) were confirmed by qPCR. The Array CGH result demonstrated one partial deletion in SOX2-OT, which encodes a member of the SOX family of transcription factors, and the exact region of the rearrangements.

CONCLUSION

According to our study, del/dup mutations could be checked prior to point mutations, SOX2-OT has a potential role in gonadal dysgenesis, and Array CGH has a prominent role in gonadal dysgenesis diagnosis.

Wide spectrum of NR5A1-related phenotypes in 46,XY and 46,XX individuals

Steroidogenic factor 1 (NR5A1, SF‐1, Ad4BP) is a transcriptional regulator of genes involved in adrenal and gonadal development and function. Mutations in NR5A1 have been among the most frequently identified genetic causes of gonadal development disorders and are associated with a wide phenotypic spectrum. In 46,XY individuals, NR5A1‐related phenotypes may range from disorders of sex development (DSD) to oligo/azoospermia, and in 46,XX individuals, from 46,XX ovotesticular and testicular DSD to primary ovarian insufficiency (POI). The most common 46,XY phenotype is atypical or female external genitalia with clitoromegaly, palpable gonads, and absence of Müllerian derivatives. Notably, an undervirilized external genitalia is frequently seen at birth, while spontaneous virilization may occur later, at puberty. In 46,XX individuals, NR5A1 mutations are a rare genetic cause of POI, manifesting as primary or secondary amenorrhea, infertility, hypoestrogenism, and elevated gonadotropin levels. Mothers and sisters of 46,XY DSD patients carrying heterozygous NR5A1 mutations may develop POI, and therefore require appropriate counseling. Moreover, the recurrent heterozygous p.Arg92Trp NR5A1 mutation is associated with variable degrees of testis development in 46,XX patients. A clear genotype‐phenotype correlation is not seen in patients bearing NR5A1 mutations, suggesting that genetic modifiers, such as pathogenic variants in other testis/ovarian‐determining genes, may contribute to the phenotypic expression. Here, we review the published literature on NR5A1‐related disease, and discuss our findings at a single tertiary center in Brazil, including ten novel NR5A1 mutations identified in 46,XY DSD patients. The ever‐expanding phenotypic range associated with NR5A1 variants in XY and XX individuals confirms its pivotal role in reproductive biology, and should alert clinicians to the possibility of NR5A1 defects in a variety of phenotypes presenting with gonadal dysfunction. Birth Defects Research (Part C) 108:309–320, 2016. © 2016 The Authors Birth Defects Research Part C: Embryo Today: Reviews Published by Wiley Periodicals, Inc.

New NR5A1 mutations and phenotypic variations of gonadal dysgenesis

Mutations in NR5A1 have been reported as a frequent cause of 46,XY disorders of sex development (DSD) associated to a broad phenotypic spectrum ranging from infertility, ambiguous genitalia, anorchia to gonadal dygenesis and female genitalia. Here we present the clinical follow up of four 46,XY DSD patients with three novel heterozygous mutations in the NR5A1 gene leading to a p.T40P missense mutation and a p.¹⁸DKVSG²²del nonframeshift deletion in the DNA-binding domain and a familiar p.Y211Tfs*83 frameshift mutation. Functional analysis of the missense and nonframeshift mutation revealed a deleterious character with loss of DNA-binding and transactivation capacity. Both, the mutations in the DNA-binding domain, as well as the familiar frameshift mutation are associated with highly variable endocrine values and phenotypic appearance. Phenotypes vary from males with spontaneous puberty, substantial testosterone production and possible fertility to females with and without Müllerian structures and primary amenorrhea. Exome sequencing of the sibling’s family revealed TBX2 as a possible modifier of gonadal development in patients with NR5A1 mutations.

A Case with late onset of ambiguous genitalia

BACKGROUND

Ambiguous genitalia is an uncommon situation that happens between 1 and 2 per every 1000 live births and falls under the umbrella diagnosis of disorders of sexual development.

CASE

In this article, we report a case of male pseudohermaphroditism with ambiguous genitalia. The proband was a 12 yr old girl without any uterus or ovarian tissues. Karyotype of the case is 46, XY. Genes involved in sexual differentiation such as AR, SRD5A2, LH, LHR, FSH, 17 B HSD and SRY genes were sequenced in both directions. No mutations were found in these genes either.

CONCLUSION

It seems advisable to be cautious in similar cases, and revise protocol for tracing the genes involved in the patients.

Disorders of sex development (DSD): not only babies with ambiguous genitalia. A practical guide for surgeons

INTRODUCTION AND METHODS

In this review, we describe the common clinical scenarios that may be present to a paediatric surgeon when a patient has a disorder of sex development (DSD). Our aim was to prepare surgeons so that they can respond with correct approaches to diagnose and manage the given situations.

RESULTS

DSD present in three distinct clinical situations: in the neonate with some abnormality of the external genitalia; in the child undergoing surgical treatment for inguinal hernia or during open or laparoscopic orchidopexy or during hypospadias correction; and at or after puberty, which may be precocious or delayed or in an adolescent girl with masculinisation at puberty. We describe the clinical features, likely diagnoses and the recommended management pathway in these scenarios.

SF-1 deficiency causes lipid accumulation in Leydig cells via suppression of STAR and CYP11A1

Genetic mutations of steroidogenic factor 1 (also known as Ad4BP or Nr5a1) have increasingly been reported in patients with 46,XY disorders of sex development (46,XY disorders of sex development). However, because the phenotype of 46,XY disorders of sex development with a steroidogenic factor 1 mutation is wide-ranging, its precise diagnosis remains a clinical problem. We previously reported the frequent occurrence of lipid accumulation in Leydig cells among patients with 46,XY disorders of sex development with a steroidogenic factor 1 mutation, an observation also reported by other authors. To address the mechanism of lipid accumulation in this disease, we examined the effects of steroidogenic factor 1 deficiency on downstream targets of steroidogenic factor 1 in in vitro and in vivo. We found that lipid accumulation in Leydig cells was enhanced after puberty in heterozygous steroidogenic factor 1 knockout mice compared with wild-type mice, and was accompanied by a significant decrease in steroidogenic acute regulatory protein and CYP11A1 expression. In mouse Leydig cell lines, steroidogenic factor 1 knockdown induced a remarkable accumulation of neutral lipids and cholesterol with reduced androgen levels. Steroidogenic factor 1 knockdown reduced the expression of steroidogenic acute regulatory protein and CYP11A1, both of which are transcriptional targets of steroidogenic factor 1 and key molecules for steroidogenesis from cholesterol in the mitochondria. Knockdown of either steroidogenic acute regulatory protein or CYP11A1 also induced lipid accumulation, and knockdown of both had an additive effect. Our data suggested that lipid accumulation in the Leydig cells of the 46,XY disorders of sex development phenotype with a steroidogenic factor 1 mutation is due, at least in part, to the suppression of steroidogenic acute regulatory protein and CYP11A1, and a resulting increase in unmetabolized cholesterol.

Functional Characterization of c.870+3_6delGAGT Splice Site Mutation in NR5A1

BACKGROUND

To date, more than 100 mutations of NR5A1 have been reported; however, mutations affecting the splice site are rare, with only two reported mutations.

OBJECTIVE

To characterize the c.870+3_6delGAGT splice mutation of NR5A1 through molecular analyses.

RESULTS

The reverse transcription polymerase chain reaction (RT-PCR) study revealed that c.870+3_6delGAGT resulted in p.A82fs*95. Mutant NR5A1 showed a reduced transactivation on the CYP11A1 and STAR promoters without a dominant negative effect.

CONCLUSION

To the best of our knowledge, this is the first report of the NR5A1 splice site mutation, which was proven to be deleterious by the RT-PCR method.

Two Unrelated Undervirilized 46,XY Males with Inherited NR5A1 Variants Identified by Whole-Exome Sequencing

BACKGROUND

Undervirilized 46,XY males with bifid scrotum often pose a diagnostic challenge, and the majority of cases typically do not receive a genetic diagnosis. NR5A1 mutations can be seen in 10-20% of the cases and are a relatively common cause of undervirilization.

METHODS

Whole-exome sequencing was utilized to study 10 undervirilized 46,XY subjects with bifid scrotum.

RESULTS

Exome sequencing identified novel NR5A1 variants, both affecting exon 7, in 2 of the 10 subjects with bifid scrotum. Subject 1 had a heterozygous frameshift variant, c.1150delC, p.Leu384fsTer1, within the ligand-binding domain inherited from his unaffected father. Subject 2 had a novel splice-site variant c.1139-2T>C, affecting the canonical splice acceptor site for exon 7 and also disrupting the ligand-binding domain. Both subjects had serum testosterone levels within the normal range as infants.

CONCLUSIONS

We describe two novel NR5A1 variants, demonstrating mutations in this gene as a common cause of milder cases of 46,XY undervirilization. Whole-exome sequencing results yielded the diagnosis in 2 out of 10 cases without a previous diagnosis, supporting the value of this approach. Significant genotype-phenotype variability was also noted with Subject 1's paternal inheritance from his unaffected father.

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

PURPOSE

We aimed to identify the genetic cause in a cohort of 11 unrelated cases and two sisters with 46,XX SRY-negative (ovo)testicular disorders of sex development (DSD).

METHODS

Whole-exome sequencing (n = 9), targeted resequencing (n = 4), and haplotyping were performed. Immunohistochemistry of sex-specific markers was performed on patients' gonads. The consequences of mutation were investigated using luciferase assays, localization studies, and RNA-seq.

RESULTS

We identified a novel heterozygous NR5A1 mutation, c.274C>T p.(Arg92Trp), in three unrelated patients. The Arg92 residue is highly conserved and located in the Ftz-F1 region, probably involved in DNA-binding specificity and stability. There were no consistent changes in transcriptional activation or subcellular localization. Transcriptomics in patient-derived lymphocytes showed upregulation of MAMLD1, a direct NR5A1 target previously associated with 46,XY DSD. In gonads of affected individuals, ovarian FOXL2 and testicular SRY-independent SOX9 expression observed.

CONCLUSIONS

We propose NR5A1, previously associated with 46,XY DSD and 46,XX primary ovarian insufficiency, as a novel gene for 46,XX (ovo)testicular DSD. We hypothesize that p.(Arg92Trp) results in decreased inhibition of the male developmental pathway through downregulation of female antitestis genes, thereby tipping the balance toward testicular differentiation in 46,XX individuals. In conclusion, our study supports a role for NR5A1 in testis differentiation in the XX gonad.Genet Med 19 4, 367-376.

A recurrent p.Arg92Trp variant in steroidogenic factor-1 (NR5A1) can act as a molecular switch in human sex development

Cell lineages of the early human gonad commit to one of the two mutually antagonistic organogenetic fates, the testis or the ovary. Some individuals with a 46,XX karyotype develop testes or ovotestes (testicular or ovotesticular disorder of sex development; TDSD/OTDSD), due to the presence of the testis-determining gene, SRY Other rare complex syndromic forms of TDSD/OTDSD are associated with mutations in pro-ovarian genes that repress testis development (e.g. WNT4); however, the genetic cause of the more common non-syndromic forms is unknown. Steroidogenic factor-1 (known as NR5A1) is a key regulator of reproductive development and function. Loss-of-function changes in NR5A1 in 46,XY individuals are associated with a spectrum of phenotypes in humans ranging from a lack of testis formation to male infertility. Mutations in NR5A1 in 46,XX women are associated with primary ovarian insufficiency, which includes a lack of ovary formation, primary and secondary amenorrhoea as well as early menopause. Here, we show that a specific recurrent heterozygous missense mutation (p.Arg92Trp) in the accessory DNA-binding region of NR5A1 is associated with variable degree of testis development in 46,XX children and adults from four unrelated families. Remarkably, in one family a sibling raised as a girl and carrying this NR5A1 mutation was found to have a 46,XY karyotype with partial testicular dysgenesis. These unique findings highlight how a specific variant in a developmental transcription factor can switch organ fate from the ovary to testis in mammals and represents the first missense mutation causing isolated, non-syndromic 46,XX testicular/ovotesticular DSD in humans.

Novel Heterozygous Mutations of NR5A1 and Their Functional Characteristics in Patients with 46,XY Disorders of Sex Development without Adrenal Insufficiency

BACKGROUND/AIMS

Heterozygous mutations of NR5A1, which encodes steroidogenic factor 1 (SF1), were identified in patients with 46,XY disorders of sex development (DSD) with normal adrenal function. This study was aimed to identify and functionally characterize mutations of NR5A1 in patients with 46,XY DSD.

METHODS

This study included 51 patients from 49 unrelated families with 46,XY DSD. Genomic DNA was extracted from peripheral blood leukocytes, and direct sequencing of all coding exons and their flanking introns of NR5A1 was performed. Transient transfections and dual-luciferase® reporter assays were performed to evaluate the effect of NR5A1 variants on transcriptional activity.

RESULTS

Four of 49 patients (8.2%) harbored a novel heterozygous sequence variant of NR5A1: c.80G>C (p.G26A), c.847T>C (p.C283R), c.1151del (p.L384Rfs*7), and c.1333G>T (p.E445*). They presented with female external genitalia with clitoromegaly in infancy or childhood, or primary amenorrhea in adolescence. In vitro functional studies of SF1 activity determined that each variant, except p.E445*, led to a reduced expression of downstream target genes and disturbed the regulation of gonadal development.

CONCLUSIONS

Loss-of-function mutations of NR5A1 are a relatively common cause of 46,XY DSD. Therefore, genetic defects of NR5A1 should be considered as an etiology in subjects with 46,XY DSD without adrenal insufficiency.

The Genetic and Environmental Factors Underlying Hypospadias

Hypospadias results from a failure of urethral closure in the male phallus and affects 1 in 200-300 boys. It is thought to be due to a combination of genetic and environmental factors. The development of the penis progresses in 2 stages: an initial hormone-independent phase and a secondary hormone-dependent phase. Here, we review the molecular pathways that contribute to each of these stages, drawing on studies from both human and mouse models. Hypospadias can occur when normal development of the phallus is disrupted, and we provide evidence that mutations in genes underlying this developmental process are causative. Finally, we discuss the environmental factors that may contribute to hypospadias and their potential immediate and transgenerational epigenetic impacts.

Steroidogenic factor 1 differentially regulates fetal and adult leydig cell development in male mice

The nuclear receptor steroidogenic factor 1 (SF-1, AD4BP, NR5A1) is a key regulator of the endocrine axes and is essential for adrenal and gonad development. Partial rescue of Nr5a1(-/-) mice with an SF-1-expressing transgene caused a hypomorphic phenotype that revealed its roles in Leydig cell development. In contrast to controls, all male rescue mice (Nr5a1(-/-);tg(+/0)) showed varying signs of androgen deficiency, including spermatogenic arrest, cryptorchidism, and poor virilization. Expression of various Leydig cell markers measured by immunohistochemistry, Western blot analysis, and RT-PCR indicated fetal and adult Leydig cell development were differentially impaired. Whereas fetal Leydig cell development was delayed in Nr5a1(-/-);tg(+/0) embryos, it recovered to control levels by birth. In contrast, Sult1e1, Vcam1, and Hsd3b6 transcript levels in adult rescue testes indicated complete blockage in adult Leydig cell development. In addition, between Postnatal Days 8 and 12, peritubular cells expressing PTCH1, SF-1, and CYP11A1 were observed in control testes but not in rescue testes, indicating SF-1 is needed for either survival or differentiation of adult Leydig cell progenitors. Cultured prepubertal rat peritubular cells also expressed SF-1 and PTCH1, but Cyp11a1 was expressed only after treatment with cAMP and retinoic acid. Together, data show SF-1 is needed for proper development of fetal and adult Leydig cells but with distinct primary functions; in fetal Leydig cells, it regulates differentiation, whereas in adult Leydig cells it regulates progenitor cell formation and/or survival.

DAX-1 (NR0B1) and steroidogenic factor-1 (SF-1, NR5A1) in human disease

DAX-1 (NR0B1) and SF-1 (NR5A1) are two nuclear receptor transcription factors that play a key role in human adrenal and reproductive development. Loss of DAX-1 function is classically associated with X-linked adrenal hypoplasia congenita. This condition typically affects boys and presents as primary adrenal insufficiency in early infancy or childhood, hypogonadotropic hypogonadism at puberty and impaired spermatogenesis. Late onset forms of this condition and variant phenotypes are increasingly recognized. In contrast, disruption of SF-1 only rarely causes adrenal insufficiency, usually in combination with testicular dysgenesis. Variants in SF-1/NR5A1 more commonly cause a spectrum of reproductive phenotypes ranging from 46,XY DSD (partial testicular dysgenesis or reduced androgen production) and hypospadias to male factor infertility or primary ovarian insufficiency. Making a specific diagnosis of DAX-1 or SF-1 associated conditions is important for long-term monitoring of endocrine and reproductive function, appropriate genetic counselling for family members, and for providing appropriate informed support for young people.

Adrenocortical growth and cancer

The adrenal gland consists of two distinct parts, the cortex and the medulla. Molecular mechanisms controlling differentiation and growth of the adrenal gland have been studied in detail using mouse models. Knowledge also came from investigations of genetic disorders altering adrenal development and/or function. During embryonic development, the adrenal cortex acquires a structural and functional zonation in which the adrenal cortex is divided into three different steroidogenic zones. Significant progress has been made in understanding adrenal zonation. Recent lineage tracing experiments have accumulated evidence for a centripetal differentiation of adrenocortical cells from the subcapsular area to the inner part of the adrenal cortex. Understanding of the mechanism of adrenocortical cancer (ACC) development was stimulated by knowledge of adrenal gland development. ACC is a rare cancer with a very poor overall prognosis. Abnormal activation of the Wnt/β-catenin as well as the IGF2 signaling plays an important role in ACC development. Studies examining rare genetic syndromes responsible for familial ACT have played an important role in identifying genetic alterations in these tumors (like TP53 or CTNNB1 mutations as well as IGF2 overexpression). Recently, genomic analyses of ACT have shown gene expression profiles associated with malignancy as well as chromosomal and methylation alterations in ACT and exome sequencing allowed to describe the mutational landscape of these tumors. This progress leads to a new classification of these tumors, opening new perspectives for the diagnosis and prognostication of ACT. This review summarizes current knowledge of adrenocortical development, growth, and tumorigenesis.

NR5A1 gene mutations: clinical, endocrine and genetic features in two girls with 46,XY disorder of sex development

BACKGROUND

Steroidogenic factor 1, encoded by the NR5A1 gene, is a key regulator of endocrine function within the hypothalamic-pituitary-steroidogenic axis. Both homozygous, compound heterozygous and heterozygous mutations in the NR5A1 gene may determine 46,XY disorders of sex development (DSD).

PATIENTS AND METHODS

NR5A1 gene sequencing was performed in a cohort of 6 patients with 46,XY DSD without specific diagnosis.

RESULTS

Heterozygous NR5A1 gene mutations were found in 2 girls, aged 0.5 years and 14 years. The older girl harbored the c.250C>T transition in exon 4 (p.Arg84Cys), previously reported in a Japanese girl. The younger girl presented a de novo novel exon 6 heterozygous frameshift mutation (c.1074dupG) in codon 359 associated with the p.Gly146Ala polymorphism the latter inherited from her father. This baby showed severe impairment of androgen secretion from the first months of life. Overt adrenal insufficiency did not occur, but the older girl showed subnormal cortisol peak after ACTH stimulation.

CONCLUSIONS

NR5A1 gene mutations are a relatively frequent cause of 46,XY DSD in humans. Clear indications for management of these individuals remain elusive, mainly when diagnosis is made in infancy. Long-term monitoring of adrenal function should be recommended.

Extensive clinical, hormonal and genetic screening in a large consecutive series of 46,XY neonates and infants with atypical sexual development

Background

One in 4500 children is born with ambiguous genitalia, milder phenotypes occur in one in 300 newborns. Conventional time-consuming hormonal and genetic work-up provides a genetic diagnosis in around 20-40% of 46,XY cases with ambiguous genitalia. All others remain without a definitive diagnosis. The investigation of milder cases, as suggested by recent reports remains controversial.

Methods

Integrated clinical, hormonal and genetic screening was performed in a sequential series of 46, XY children, sex-assigned male, who were referred to our pediatric endocrine service for atypical genitalia (2007–2013).

Results

A consecutive cohort of undervirilized 46,XY children with external masculinization score (EMS) 2–12, was extensively investigated. In four patients, a clinical diagnosis of Kallmann syndrome or Mowat-Wilson syndrome was made and genetically supported in 2/3 and 1/1 cases respectively. Hormonal data were suggestive of a (dihydro)testosterone biosynthesis disorder in four cases, however no HSD17B3 or SRD5A2 mutations were found. Array-CGH revealed a causal structural variation in 2/6 syndromic patients. In addition, three novel NR5A1 mutations were found in non-syndromic patients. Interestingly, one mutation was present in a fertile male, underlining the inter- and intrafamilial phenotypic variability of NR5A1-associated phenotypes. No AR, SRY or WT1 mutations were identified.

Conclusion

Overall, a genetic diagnosis could be established in 19% of non-syndromic and 33% of syndromic cases. There is no difference in diagnostic yield between patients with more or less pronounced phenotypes, as expressed by the external masculinisation score (EMS). The clinical utility of array-CGH is high in syndromic cases. Finally, a sequential gene-by-gene approach is time-consuming, expensive and inefficient. Given the low yield and high expense of Sanger sequencing, we anticipate that massively parallel sequencing of gene panels and whole exome sequencing hold promise for genetic diagnosis of 46,XY DSD boys with an undervirilized phenotype.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-014-0209-2) contains supplementary material, which is available to authorized users.

Intrauterine growth restriction and hypospadias: is there a connection?

Hypospadias is one of the most common congenital malformations of the genitourinary tract in males. It is an incomplete fusion of urethral folds early in fetal development and may be associated with other malformations of the genital tract. The etiology is poorly understood and may be hormonal, genetic, or environmental, but most often is idiopathic or multifactorial. Among many possible risk factors identified, of particular importance is low birth weight, which is defined in various ways in the literature. No mechanism has been identified for the association of low birth weight and hypospadias, but some authors propose placental insufficiency as a common inciting factor. Currently, there is no standardized approach for evaluating children with hypospadias in the setting of intrauterine growth restriction. We reviewed the available published literature on the association of hypospadias and growth restriction to determine whether it should be considered a separate entity within the category of disorders of sexual differentiation.

DSDs: genetics, underlying pathologies and psychosexual differentiation

Mammalian sex determination is the unique process whereby a single organ, the bipotential gonad, undergoes a developmental switch that promotes its differentiation into either a testis or an ovary. Disruptions of this complex genetic process during human development can manifest as disorders of sex development (DSDs). Sex development can be divided into two distinct processes: sex determination, in which the bipotential gonads form either testes or ovaries, and sex differentiation, in which the fully formed testes or ovaries secrete local and hormonal factors to drive differentiation of internal and external genitals, as well as extragonadal tissues such as the brain. DSDs can arise from a number of genetic lesions, which manifest as a spectrum of gonadal (gonadal dysgenesis to ovotestis) and genital (mild hypospadias or clitoromegaly to ambiguous genitalia) phenotypes. The physical attributes and medical implications associated with DSDs confront families of affected newborns with decisions, such as gender of rearing or genital surgery, and additional concerns, such as uncertainty over the child's psychosexual development and personal wishes later in life. In this Review, we discuss the underlying genetics of human sex determination and focus on emerging data, genetic classification of DSDs and other considerations that surround gender development and identity in individuals with DSDs.

Analysis of the gene coding for steroidogenic factor 1 (SF1, NR5A1) in a cohort of 50 Egyptian patients with 46,XY disorders of sex development

OBJECTIVE

Steroidogenic factor 1 (SF1, NR5A1) is a key transcriptional regulator of genes involved in the hypothalamic-pituitary-gonadal axis. Recently, SF1 mutations were found to be a frequent cause of 46,XY disorders of sex development (DSD) in humans. We investigate the frequency of NR5A1 mutations in an Egyptian cohort of XY DSD.

DESIGN

Clinical assessment, endocrine evaluation and genetic analysis of 50 Egyptian XY DSD patients (without adrenal insufficiency) with a wide phenotypic spectrum.

METHODS

Molecular analysis of NR5A1 gene by direct sequencing followed by in vitro functional analysis of the two novel missense mutations detected.

RESULTS

Three novel heterozygous mutations of the coding region in patients with hypospadias were detected. p.Glu121AlafsX25 results in severely truncated protein, p.Arg62Cys lies in DNA-binding zinc finger, whereas p.Ala154Thr lies in the hinge region of SF1 protein. Transactivation assays using reporter constructs carrying promoters of anti-Müllerian hormone (AMH), CYP11A1 and TESCO core enhancer of Sox9 showed that p.Ala154Thr and p.Arg62Cys mutations result in aberrant biological activity of NR5A1. A total of 17 patients (34%) harboured the p.Gly146Ala polymorphism.

CONCLUSION

We identified two novel NR5A1 mutations showing impaired function in 23 Egyptian XY DSD patients with hypospadias (8.5%). This is the first study searching for NR5A1 mutations in oriental patients from the Middle East and Arab region with XY DSD and no adrenal insufficiency, revealing a frequency similar to that in European patients (6.5-15%). We recommend screening of NR5A1 in patients with hypospadias and gonadal dysgenesis. Yearly follow-ups of gonadal function and early cryoconservation of sperms should be performed in XY DSD patients with NR5A1 mutations given the risk of future fertility problems due to early gonadal failure.