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

State of the art review in gonadal dysgenesis: challenges in diagnosis and management

Gonadal dysgenesis, a condition in which gonadal development is interrupted leading to gonadal dysfunction, is a unique subset of disorders of sexual development (DSD) that encompasses a wide spectrum of phenotypes ranging from normally virilized males to slightly undervirilized males, ambiguous phenotype, and normal phenotypic females. It presents specific challenges in diagnostic work-up and management. In XY gonadal dysgenesis, the presence of a Y chromosome or Y-chromosome material renders the patient at increased risk for developing gonadal malignancy. No universally accepted guidelines exist for identifying the risk of developing a malignancy or for determining either the timing or necessity of performing a gonadectomy in patients with XY gonadal dysgenesis. Our goal was to evaluate the literature and develop evidence-based medicine guidelines with respect to the diagnostic work-up and management of patients with XY gonadal dysgenesis. We reviewed the published literature and used the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) system when appropriate to grade the evidence and to provide recommendations for the diagnostic work-up, malignancy risk stratification, timing or necessity of gonadectomy, role of gonadal biopsy, and ethical considerations for performing a gonadectomy. Individualized health care is needed for patients with XY gonadal dysgenesis, and the decisions regarding gonadectomy should be tailored to each patient based on the underlying diagnosis and risk of malignancy. Our recommendations, based on the evidence available, add an important component to the diagnostic and management armament of physicians who treat patients with these conditions.

Review of genetic and environmental factors leading to hypospadias

Hypospadias is one of the most common congenital malformations, affecting about 4-6 males per 1000 male births, and ranging in severity from a urethral meatus that is slightly off-center to a meatus in the perineal area. Over the past three decades its prevalence may have increased due to changes in reporting of mild cases and/or increased survival of low birth weight infants due to improved neonatal care. However, despite the increasing numbers of males with hypospadias, the overall etiology remains unclear and likely multifactorial in nature. The purpose of this review article is to provide a comprehensive overview of the various factors implicated in hypospadias etiology, including genetic and environmental factors. In addition, we list syndromes in which hypospadias is a relatively common association and delineate the areas that require further investigation in an effort to understand this condition.

46,XY disorder of sexual development resulting from a novel monoallelic mutation (p.Ser31Phe) in the steroid 5α-reductase type-2 (SRD5A2) gene

Inactivating mutations of the 5α-steroid reductase type-2 (SRD5A2) gene result in a broad spectrum of masculinization defects, ranging from a male phenotype with hypospadias to a female phenotype with Wolffian structures. Molecular studies of the SRD5A2 revealed a new heterozygous gene variant within the coding region that results in phenotypic expression. A c.92C>T transition changing serine to phenylalanine at codon 31 of exon 1 (p.Ser31Phe) was identified in a patient with 46,XY disorder of sexual development who displayed glandular hypospadias with micropenis and bilateral cryptorchidism. The restoration of the p.Ser31Phe mutation by site-directed mutagenesis and transient expression assays using cultured HEK-293 cells showed that this novel substitution does not abolish but does deregulate the catalytic efficiency of the enzyme. Thus, the maximum velocity (V_max) value was higher for the mutant enzyme (22.5 ± 6.9 nmol DHT mg protein⁻¹ h⁻¹) than for the wild-type enzyme (9.8 ± 2.0 nmol DHT mg protein⁻¹ h⁻¹). Increased in vitro activity of the p.Ser31Phe mutant suggested an activating effect. This case provides evidence that heterozygous missense mutations in SRD5A2 may induce the abnormal development of male external genitalia.

Spreading the clinical window for diagnosing fetal-onset hypogonadism in boys

In early fetal development, the testis secretes - independent of pituitary gonadotropins - androgens and anti-Müllerian hormone (AMH) that are essential for male sex differentiation. In the second half of fetal life, the hypothalamic-pituitary axis gains control of testicular hormone secretion. Follicle-stimulating hormone (FSH) controls Sertoli cell proliferation, responsible for testis volume increase and AMH and inhibin B secretion, whereas luteinizing hormone (LH) regulates Leydig cell androgen and INSL3 secretion, involved in the growth and trophism of male external genitalia and in testis descent. This differential regulation of testicular function between early and late fetal periods underlies the distinct clinical presentations of fetal-onset hypogonadism in the newborn male: primary hypogonadism results in ambiguous or female genitalia when early fetal-onset, whereas it becomes clinically undistinguishable from central hypogonadism when established later in fetal life. The assessment of the hypothalamic-pituitary-gonadal axis in male has classically relied on the measurement of gonadotropin and testosterone levels in serum. These hormone levels normally decline 3-6 months after birth, thus constraining the clinical evaluation window for diagnosing male hypogonadism. The advent of new markers of gonadal function has spread this clinical window beyond the first 6 months of life. In this review, we discuss the advantages and limitations of old and new markers used for the functional assessment of the hypothalamic-pituitary-testicular axis in boys suspected of fetal-onset hypogonadism.

Acidic residue Glu199 increases SUMOylation level of nuclear hormone receptor NR5A1

Steroidogenic factor 1 (NR5A1/SF1) is a well-known master regulator in controlling adrenal and sexual development, as well as regulating numerous genes involved in adrenal and gonadal steroidogenesis. Several studies including ours have demonstrated that NR5A1 can be SUMOylated on lysine 194 (K194, the major site) and lysine 119 (K119, the minor site), and the cycle of SUMOylation regulates NR5A1’s transcriptional activity. An extended consensus negatively charged amino acid-dependent SUMOylation motif (NDSM) enhances the specificity of substrate modification by SUMO has been reported; however, the mechanism of NDSM for NR5A1 remains to be clarified. In this study, we investigated the functional significance of the acidic residue located downstream from the core consensus SUMO site of NR5A1. Here we report that E199A (glutamic acid was replaced with alanine) of NR5A1 reduced, but not completely abolished, its SUMOylation level. We next characterized the functional role of NR5A1 E199A on target gene expression and protein levels. We found that E199A alone, as well as combination with K194R, increased Mc2r and Cyp19a1 reporter activities. Moreover, E199A alone as well as combination with K194R enhanced NR5A1-mediated STAR protein levels in mouse adrenocortical cancer Y1 cells. We also observed that E199A increased interaction of NR5A1 with CDK7 and SRC1. Overall, we provide the evidence that the acidic residue (E199) located downstream from the core consensus SUMO site of NR5A1 is, at least in part, required for SUMOylation of NR5A1 and for its mediated target gene and protein expression.

Screening and familial characterization of copy-number variations in NR5A1 in 46,XY disorders of sex development and premature ovarian failure

The NR5A1 gene encodes for steroidogenic factor 1, a nuclear receptor that regulates proper adrenal and gonadal development and function. Mutations identified by NR5A1 sequencing have been associated with disorders of sex development (DSD), ranging from sex reversal to severe hypospadias in 46,XY patients and premature ovarian failure (POF) in 46,XX patients. Previous reports have identified four families with a history of both 46,XY DSD and 46,XX POF carrying segregating NR5A1 sequence mutations. Recently, three 46,XY DSD sporadic cases with NR5A1 microdeletions have been reported. Here, we identify the first NR5A1 microdeletion transmitted in a pedigree with both 46,XY DSD and 46,XX POF. A 46,XY individual with DSD due to gonadal dysgenesis was born to a young mother who developed POF. Array CGH analysis revealed a maternally inherited 0.23 Mb microdeletion of chromosome 9q33.3, including the NR5A1 gene. Based on this finding, we screened patients with unexplained 46,XY DSD (n = 11), proximal hypospadias (n = 21) and 46,XX POF (n = 36) for possible NR5A1 copy-number variations (CNVs) via multiplex ligation-dependent probe amplification (MLPA), but did not identify any additional CNVs involving NR5A1. These data suggest that NR5A1 CNVs are an infrequent cause of these disorders but that array CGH and MLPA are useful genomic screening tools to uncover the genetic basis of such unexplained cases. This case is the first report of a familial NR5A1 CNV transmitting in a pedigree, causing both the male and female phenotypes associated with NR5A1 mutations, and the first report of a NR5A1 CNV associated with POF.

Review and management of 46,XY disorders of sex development

Disorders of sex development (DSD) among 46,XY individuals are rare and challenging conditions. Abnormalities of karyotype, gonadal formation, androgen synthesis, and androgen action are responsible for the multiple disorders that result in undervirilization during development. Phenotypic appearance and timing of presentation are quite variable. The focus of treatment has shifted from early gender assignment and corrective surgery to careful diagnosis, proper education of patients and their families, and individualized treatment by a multi-disciplinary team. The modern management of these patients is difficult and controversial. Conflicting data on long-term outcomes of these individuals have been reported in the literature. The various etiologies of 46,XY DSD, current approaches to diagnosis and treatment, and reported long-term results are reviewed.

A report of two novel NR5A1 mutation families: possible clinical phenotype of psychiatric symptoms of anxiety and/or depression

OBJECTIVE

NR5A1 or steroidogenic factor 1 is a nuclear receptor that plays important roles in the hypothalamus-pituitary-steroidogenic axis. The clinical phenotype of most 46,XY mutation carriers includes disorders of sex development (DSD) without adrenal insufficiency, whereas 46,XX mutation carriers have phenotypes ranging from no symptoms to ovarian insufficiency. Although genetically engineered ventromedial hypothalamus-specific Nr5a1 knockout mice show anxiety behaviour, no psychiatric symptoms have been reported in human NR5A1 mutation carriers. We report clinical and molecular findings for individuals (from two families) with NR5A1 mutations, showing psychiatric symptoms.

DESIGN AND METHODS

We screened for NR5A1 mutations in a cohort of 34 patients with 46,XY DSD using PCR-based sequencing. Psychiatric symptoms were assessed using mental health assessment tools and structured clinical interviews. Functional properties of detected mutant NR5A1s were studied in silico and in vitro, including three-dimensional (3D) mutation models, subcellular NR5A1 protein localization and transactivation assays.

RESULTS

We found 2 (46,XY) patients with NR5A1 heterozygous novel mutations (p.D257fs and p.V424del), which were transmitted from their respective mothers. The patients' clinical findings indicated DSD without adrenal insufficiency. Both mothers showed psychiatric symptoms, including excessive anxiety and/or depression. The mother and grandmother of one patient had premature ovarian insufficiency. Functional studies showed altered 3D models of p.V424del and normal subcellular NR5A1 localization and impaired transcriptional activation without dominant-negative effects in both mutations.

CONCLUSIONS

We found 2 (46,XX) NR5A1 mutation carriers with excessive anxiety and/or depression. These results suggest that excessive anxiety and/or depression are possible clinical phenotypes of 46,XX NR5A1 mutations.

A novel NR5A1 variant in an infant with elevated testosterone from an Australasian cohort of 46,XY patients with disorders of sex development

BACKGROUND

NR5A1 loss-of-function mutations are increasingly found to be the cause of 46,XY disorders of sex development (DSD).

OBJECTIVE

To determine the presence of NR5A1 mutations in an Australasian cohort of 17 46,XY DSD patients with presumed androgen insensitivity syndrome (AIS) who were negative for androgen receptor gene (AR) mutation.

DESIGN

Exons 2-7 of NR5A1 were PCR amplified and sequenced. Gene expression and cellular localization studies were performed on a novel NR5A1 variant c.74A>G (p.Y25C) identified in this study.

RESULTS

We identified one novel mutation, c.74A>G (p.Y25C) in a patient characterized by penoscrotal hypospadias with bifid scrotum. He had elevated testosterone and gonadotropins in early infancy. Functional analysis of p.Y25C in vitro demonstrated reduced transcriptional activation by SF-1 and partially impaired nuclear localization in a proportion of transfected human adrenal NCI-H295R cells.

CONCLUSION

This is the first reported case of a DSD patient with a NR5A1 mutation and elevated testosterone levels. Our finding supports evaluation of NR5A1 mutations in 46,XY DSD patients with a range of testosterone levels.

Understanding the genetic aetiology in patients with XY DSD

BACKGROUND

Disorders of sex development (DSD) consist of a wide range of disorders and are commoner in those with an XY karyotype. In over half of these cases who have a 46,XY karyotype and who are raised as boys, the underlying aetiology remains unclear.

AREAS OF AGREEMENT

Identification of the underlying genetic abnormality may predict long-term outcome. However, genetic abnormalities that are associated with XY DSD manifest themselves with a wide range of phenotype. To understand the aetiology as well as the phenotypic variation, there is a need to harness the advanced genetic technology that is now available.

AREAS OF CONTROVERSY

The point at which genetic analysis should be undertaken in the course of investigations is unclear. In addition, there is little agreement on the most effective approach for genetic analysis that will be of clinical benefit to the patient.

AREAS TIMELY FOR DEVELOPING RESEARCH

There is a need to understand and improve the clinical utility of genetic analysis in the clinical setting of the patient with a suspected DSD. This will be even more important when parallel gene sequencing identifies variations in multiple genes.

The p.G146A and p.P125P polymorphisms in the steroidogenic factor-1 (SF-1) gene do not affect the risk for hypospadias in Caucasians

Hypospadias is a frequent congenital malformation in boys and is characterized by incomplete fusion of the urethral folds. The steroidogenic factor-1 (SF-1, NR5A1) gene plays a key role in hypothalamic-pituitary-steroidogenic organ development, and has previously been reported to be mutated in individuals with 46,XY disorder of sex development. Here, we investigated the role of SF-1 in hypospadias, a milder form of 46,XY disorder of sex development. We performed direct sequencing analysis of the SF-1 gene in 2 male Caucasian twins exhibiting very severe hypospadias, and in 95 Caucasian boys with mild and severe hypospadias. We further extended the analysis by investigating 332 mild and severe hypospadias cases and 422 male controls using TaqMan assays. Our sequencing revealed a novel heterozygous p.R313H (c.938G>A) missense mutation in each twin, and no mutations in the 95 Caucasian cases. Instead, a missense p.G146A (c.437G>C), and a silent known p.P125P (c.375C>T) polymorphism, respectively, was found in several of the latter cases. Further investigation of the 2 polymorphisms in the larger material of cases and controls showed no significant genotypic or allelic association. In conclusion, the SF-1 gene may not play a significant role in the development of hypospadias in Caucasians.

Steroidogenic factor-1 and human disease

Steroidogenic factor-1 (SF-1) (Ad4BP, NR5A1) is a nuclear receptor that plays a key role in adrenal and reproductive development and function. Deletion of the gene encoding Sf-1 (Nr5a1) in mice results in severe developmental defects of the adrenal gland and gonad. Consequently, initial work on the potential effects of SF-1 disruption in humans focused on individuals with primary adrenal failure, a 46,XY karyotype, complete gonadal dysgenesis, and Müllerian structures. This is a rare phenotype, but has been reported on two occasions, because of alterations that affect key DNA-binding domains of SF-1. Attention then turned to a potential wider role of SF-1 in human adrenal and reproductive disorders. Although changes in SF-1 only very rarely cause isolated adrenal failure, it is emerging that variations in SF-1 are a surprisingly frequent cause of reproductive dysfunction in humans. In 46,XY disorders of sex development, a spectrum of phenotypes has been reported including severe and partial forms of gonadal (testicular) dysgenesis, hypospadias, anorchia with microphallus, and even male factor infertility. In 46,XX females, alterations in SF-1 are associated with primary ovarian insufficiency. Thus, SF-1 seems be a more significant factor in human reproductive health than was first envisioned, with implications for adults as well as children.

Gender Development in 46,XY DSD: Influences of Chromosomes, Hormones, and Interactions with Parents and Healthcare Professionals

Variables that impact gender development in humans are difficult to evaluate. This difficulty exists because it is not usually possible to tease apart biological influences on gender from social variables. People with disorders of sex development, or DSD, provide important opportunities to study gender within individuals for whom biologic components of sex can be discordant with social components of gender. While most studies of gender development in people with 46,XY DSD have historically emphasized the importance of genes and hormones on gender identity and gender role, more recent evidence for a significant role for socialization exists and is considered here. For example, the influence of parents' perceptions of, and reactions to, DSD are considered. Additionally, the impact of treatments for DSD such as receiving gonadal surgeries or genitoplasty to reduce genital ambiguity on the psychological development of people with 46,XY DSD is presented. Finally, the role of multi-disciplinary care including access to peer support for advancing medical, surgical and psychosexual outcomes of children and adults with 46,XY DSD, regardless of sex of rearing, is discussed.

Testosterone production during puberty in two 46,XY patients with disorders of sex development and novel NR5A1 (SF-1) mutations

BACKGROUND

Steroidogenic factor 1 (SF-1, NR5A1) is a key transcriptional regulator of many genes involved in the hypothalamic-pituitary-gonadal axis and mutations in NR5A1 can result in 46,XY disorders of sex development (DSD). Patients with this condition typically present with ambiguous genitalia, partial gonadal dysgenesis, and absent/rudimentary Müllerian structures. In these cases, testosterone is usually low in early infancy, indicating significantly impaired androgen synthesis. Further, Sertoli cell dysfunction is seen (low inhibin B, anti-Müllerian hormone). However, gonadal function at puberty in patients with NR5A1 mutations is unknown.

SUBJECTS AND METHODS

Clinical assessment, endocrine evaluation, and genetic analysis were performed in one female and one male with 46,XY DSD who showed spontaneous virilization during puberty. The female patient presented at adolescence with clitoral hypertrophy, whereas the male patient presented at birth with severe hypospadias and entered puberty spontaneously. Molecular analysis of NR5A1 was performed followed by in vitro functional analysis of the two novel mutations detected.

RESULTS

Testosterone levels were normal during puberty in both patients. Analysis of NR5A1 revealed two novel heterozygous missense mutations in the ligand-binding domain of SF-1 (patient 1: p.L376F; patient 2: p.G328V). The mutant proteins showed reduced transactivation of the CYP11A promoter in vitro.

CONCLUSION

Patients with 46,XY DSD and NR5A1 mutations can produce sufficient testosterone for spontaneous virilization during puberty. Phenotypic females (46,XY) with NR5A1 mutations can present with clitoromegaly at puberty, a phenotype similar to other partial defects of androgen synthesis or action. Testosterone production in 46,XY males with NR5A1 mutations can be sufficient for virilization at puberty. As progressive gonadal dysgenesis is likely, gonadal function should be monitored in adolescence and adulthood, and early sperm cryopreservation considered in male patients if possible.

Ten novel mutations in the NR5A1 gene cause disordered sex development in 46,XY and ovarian insufficiency in 46,XX individuals

CONTEXT

Steroidogenic factor-1 (SF-1/NR5A1) is a nuclear receptor that regulates adrenal and reproductive development and function. NR5A1 mutations have been detected in 46,XY individuals with disorders of sexual development (DSD) but apparently normal adrenal function and in 46,XX women with normal sexual development yet primary ovarian insufficiency (POI).

OBJECTIVE

A group of 100 46,XY DSD and two POI was studied for NR5A1 mutations and their impact.

DESIGN

Clinical, biochemical, histological, genetic, and functional characteristics of the patients with NR5A1 mutations are reported.

SETTING

Patients were referred from different centers in Spain, Switzerland, and Turkey. Histological and genetic studies were performed in Barcelona, Spain. In vitro studies were performed in Bern, Switzerland.

PATIENTS

A total of 65 Spanish and 35 Turkish patients with 46,XY DSD and two Swiss 46,XX patients with POI were investigated.

MAIN OUTCOME

Ten novel heterozygote NR5A1 mutations were detected and characterized (five missense, one nonsense, three frameshift mutations, and one duplication).

RESULTS

The novel NR5A1 mutations were tested in vitro by promoter transactivation assays showing grossly reduced activity for mutations in the DNA binding domain and variably reduced activity for other mutations. Dominant negative effect of the mutations was excluded. We found high variability and thus no apparent genotype-structure-function-phenotype correlation. Histological studies of testes revealed vacuolization of Leydig cells due to fat accumulation.

CONCLUSIONS

SF-1/NR5A1 mutations are frequently found in 46,XY DSD individuals (9%) and manifest with a broad phenotype. Testes histology is characteristic for fat accumulation and degeneration over time, similar to findings observed in patients with lipoid congenital adrenal hyperplasia (due to StAR mutations). Genotype-structure-function-phenotype correlation remains elusive.

Mammalian sex determination—insights from humans and mice

Disorders of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. Many of the genes required for gonad development have been identified by analysis of DSD patients. However, the use of knockout and transgenic mouse strains have contributed enormously to the study of gonad gene function and interactions within the development network. Although the genetic basis of mammalian sex determination and differentiation has advanced considerably in recent years, a majority of 46,XY gonadal dysgenesis patients still cannot be provided with an accurate diagnosis. Some of these unexplained DSD cases may be due to mutations in novel DSD genes or genomic rearrangements affecting regulatory regions that lead to atypical gene expression. Here, we review our current knowledge of mammalian sex determination drawing on insights from human DSD patients and mouse models.

Aetiology of hypospadias: a systematic review of genes and environment

BACKGROUND

Hypospadias is a common congenital malformation of the male external genitalia. Most cases have an unknown aetiology, which is probably a mix of monogenic and multifactorial forms, implicating both genes and environmental factors. This review summarizes current knowledge about the aetiology of hypospadias.

METHODS

Pubmed was used to identify studies on hypospadias aetiology published between January 1995 and February 2011. Reference lists of the selected manuscripts were also searched to identify additional studies, including those published before 1995.

RESULTS

The search provided 922 articles and 169 articles were selected for this review. Studies screening groups of patients with hypospadias for single gene defects found mutations in WT1, SF1, BMP4, BMP7, HOXA4, HOXB6, FGF8, FGFR2, AR, HSD3B2, SRD5A2, ATF3, MAMLD1, MID1 and BNC2. However, most investigators are convinced that single mutations do not cause the majority of isolated hypospadias cases. Indeed, associations were found with polymorphisms in FGF8, FGFR2, AR, HSD17B3, SRD5A2, ESR1, ESR2, ATF3, MAMLD1, DGKK, MID1, CYP1A1, GSTM1 and GSTT1. In addition, gene expression studies indentified CTGF, CYR61 and EGF as candidate genes. Environmental factors consistently implicated in hypospadias are low birthweight, maternal hypertension and pre-eclampsia, suggesting that placental insufficiency may play an important role in hypospadias aetiology. Exogenous endocrine-disrupting chemicals have the potential to induce hypospadias but it is unclear whether human exposure is high enough to exert this effect. Other environmental factors have also been associated with hypospadias but, for most, the results are inconsistent.

CONCLUSIONS

Although a number of contributors to the aetiology of hypospadias have been identified, the majority of risk factors remain unknown.

Pubertal androgenization and gonadal histology in two 46,XY adolescents with NR5A1 mutations and predominantly female phenotype at birth

OBJECTIVE

Most patients with NR5A1 (SF-1) mutations and poor virilization at birth are sex-assigned female and receive early gonadectomy. Although studies in pituitary-specific Sf-1 knockout mice suggest hypogonadotropic hypogonadism, little is known about endocrine function at puberty and on germ cell tumor risk in patients with SF-1 mutations. This study reports on the natural course during puberty and on gonadal histology in two adolescents with SF-1 mutations and predominantly female phenotype at birth.

DESIGN AND METHODS

Clinical and hormonal data and histopathological studies are reported in one male and one female adolescent with, respectively, a nonsense mutation (c.9T>A, p.Tyr3X) and a deletion of the first two coding exons (NCBI36/hg18 Chr9:g.(126306276-126307705)_(126303229-126302828)del) of NR5A1, both predicted to fully disrupt gene function.

RESULTS

LH and testosterone concentrations were in the normal male range, virilization was disproportionate to the neonatal phenotype. In the girl, gonadectomy at 13 years revealed incomplete spermatogenesis and bilateral precursor lesions of testicular carcinoma in situ. In the boy, at the age of 12, numerous germ cells without signs of malignancy were present in bilateral testicular biopsy specimen.

CONCLUSIONS

In SF-1 mutations, the neonatal phenotype poorly predicts virilization at puberty. Even in poorly virilized cases at birth, male gender assignment may allow spontaneous puberty without signs of hypogonadotropic hypogonadism, and possibly fertility. Patients with SF-1 mutations are at increased risk for malignant germ cell tumors. In case of preserved gonads, early orchidopexy and germ cell tumor screening is warranted. The finding of premalignant and/or malignant changes should prompt gonadectomy or possibly irradiation.

Limited contribution of NR5A1 (SF-1) mutations in women with primary ovarian insufficiency (POI)

OBJECTIVE

To evaluate the significance of NR5A1 mutations in a large, well-phenotyped cohort of women with primary ovarian insufficiency (POI). Mutations in the NR5A1 gene (SF-1) were previously described in disorders of sexual development and adrenal insufficiency. Recently, a high frequency of NR5A1 gene mutations was reported in a small group of women with POI.

DESIGN

Cross-sectional cohort study.

SETTING

University hospital.

PATIENT(S)

Well-phenotyped women (n = 386) with secondary amenorrhea and diagnosed with POI, including women with familial POI (n = 77).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The entire coding region and splice sites of the NR5A1 gene were PCR-amplified and sequenced. The pathogenicity of identified mutations was predicted in silico by assessing Align-GVGD class and Grantham score.

RESULT(S)

Sequencing was successful in 356 patients with POI. In total, 9 mutations were identified in 10 patients. Five of these mutations concerned novel nonconservative mutations occurring in 5 patients. Prediction of effect on protein function showed low to intermediate pathogenicity for all nonconservative mutations. The overall NR5A1 gene mutation rate was 1.4%.

CONCLUSION(S)

The current study demonstrates that mutations in the NR5A1 gene are rare in women with POI. Primary ovarian insufficiency remains unexplained in the great majority of patients; therefore, continued efforts are needed to elucidate its underlying genetic factors.

Mutation analysis of NR5A1 encoding steroidogenic factor 1 in 77 patients with 46, XY disorders of sex development (DSD) including hypospadias

Background

Mutations of the NR5A1 gene encoding steroidogenic factor-1 have been reported in association with a wide spectrum of 46,XY DSD (Disorder of Sex Development) phenotypes including severe forms of hypospadias.

Methodology/Principal Findings

We evaluated the frequency of NR5A1 gene mutations in a large series of patients presenting with 46,XY DSD and hypospadias. Based on their clinical presentation 77 patients were classified either as complete or partial gonadal dysgenesis (uterus seen at genitography and/or surgery, n = 11), ambiguous external genitalia without uterus (n = 33) or hypospadias (n = 33). We identified heterozygous NR5A1 mutations in 4 cases of ambiguous external genitalia without uterus (12.1%; p.Trp279Arg, pArg39Pro, c.390delG, c140_141insCACG) and a de novo missense mutation in one case with distal hypospadias (3%; p.Arg313Cys). Mutant proteins showed reduced transactivation activity and mutants p.Arg39Pro and p.Arg313Cys did not synergize with the GATA4 cofactor to stimulate reporter gene activity, although they retained their ability to physically interact with the GATA4 protein.

Conclusions/Significance

Mutations in NR5A1 were observed in 5/77 (6.5%) cases of 46,XY DSD including hypospadias. Excluding the cases of 46,XY gonadal dysgenesis the incidence of NR5A1 mutations was 5/66 (7.6%). An individual with isolated distal hypopadias carried a de novo heterozygous missense mutation, thus extending the range of phenotypes associated with NR5A1 mutations and suggesting that this group of patients should be screened for NR5A1 mutations.

Analysis of the Wilms' tumor suppressor gene (WT1) in patients 46,XY disorders of sex development

CONTEXT

The Wilms' tumor suppressor gene (WT1) is one of the major regulators of early gonadal and kidney development. WT1 mutations have been identified in 46,XY disorders of sex development (DSD) with associated kidney disease and in few isolated forms of 46,XY DSD.

OBJECTIVE

The objective of the study was the evaluation of WT1 mutations in different phenotypes of isolated 46,XY DSD and clinical consequences.

DESIGN

The design of the study was: 1) sequencing of the WT1 gene in 210 patients with 46,XY DSD from the German DSD network, consisting of 150 males with severe hypospadias (70 without cryptorchidism, 80 with at least one cryptorchid testis), 10 males with vanishing testes syndrome, and 50 raised females with partial to complete 46,XY gonadal dysgenesis; and 2) genotype-phenotype correlation of our and all published patients with 46,XY DSD and WT1 mutations.

RESULTS

We have detected WT1 mutations in six of 80 patients with severe hypospadias (7.5%) and at least one cryptorchid testis and in one of 10 patients with vanishing testes syndrome (10%). All patients except one developed Wilms' tumor and/or nephropathy in childhood or adolescence.

CONCLUSION

WT1 analysis should be performed in newborns with complex hypospadias with at least one cryptorchid testis and in isolated 46,XY partial to complete gonadal dysgenesis. Kidney disease might not develop until later life in these cases. WT1 analysis is mandatory in all 46,XY DSD with associated kidney disease. WT1 analysis is not indicated in newborns with isolated hypospadias without cryptorchidism. Patients with WT1 mutations should be followed up closely because the risk of developing a Wilms' tumor, nephropathy, and/or gonadal tumor is very high.

Partial deletion of the NR5A1 (SF1) gene detected by synthetic probe MLPA in a patient with XY gonadal disorder of sex development

Steroidogenic factor 1 (SF1, officially NR5A1) is a nuclear receptor involved in adrenal and gonadal development. NR5A1 mutations have been identified in patients with various forms of 46,XY disorders of sex development (DSD), including complete gonadal dysgenesis with or without adrenal insufficiency, mild testicular dysgenesis with ambiguous external genitalia or female external genitalia with clitoromegaly, and penoscrotal hypospadias. We developed a synthetic probe set for MLPA analysis of the NR5A1 gene covering its 7 exons and analyzed 20 patients with 46,XY gonadal DSD in whom analyses failed to identify a genetic cause. We identified a partial NR5A1 deletion affecting exons 2 and 3, leading to NR5A1 haploinsufficiency in 1 patient presenting with female external genitalia with clitoromegaly, absence of a uterus, and mildly dysgenetic testes. This is the first partial NR5A1 gene deletion identified by MLPA in a patient with 46,XY gonadal DSD. This finding stresses the importance of investigating copy number changes, even at the exon level, in genes involved in gonadal DSD. As NR5A1 mutations can cause a wide spectrum of DSD with relatively high frequency, the analysis of the NR5A1 gene by MLPA is quite important and should be extended to larger groups of patients.

Steroidogenic factor-1 (SF-1, NR5A1) and human disease

Steroidogenic factor-1 (SF-1, Ad4BP, encoded by NR5A1) is a key regulator of adrenal and reproductive development and function. Based upon the features found in Nr5a1 null mice, initial attempts to identify SF-1 changes in humans focused on those rare individuals with primary adrenal failure, a 46,XY karyotype, complete gonadal dysgenesis and Müllerian structures. Although alterations affecting DNA-binding of SF-1 were found in two such cases, disruption of SF-1 is not commonly found in patients with adrenal failure. In contrast, it is emerging that variations in SF-1 can be found in association with a range of human reproductive phenotypes such as 46,XY disorders of sex development (DSD), hypospadias, anorchia, male factor infertility, or primary ovarian insufficiency in women. Overexpression or overactivity of SF-1 is also reported in some adrenal tumors or endometriosis. Therefore, the clinical spectrum of phenotypes associated with variations in SF-1 is expanding and the importance of this nuclear receptor in human endocrine disease is now firmly established.

Loss-of-function mutation in GATA4 causes anomalies of human testicular development

Approximately 1 of every 250 newborns has some abnormality of genital and/or gonadal development. However, a specific molecular cause is identified in only 20% of these cases of disorder of sex development (DSD). We identified a family of French origin presenting with 46,XY DSD and congenital heart disease. Sequencing of the ORF of GATA4 identified a heterozygous missense mutation (p.Gly221Arg) in the conserved N-terminal zinc finger of GATA4. This mutation was not observed in 450 ancestry-matched control individuals. The mutation compromised the ability of the protein to bind to and transactivate the anti-Müllerian hormone (AMH) promoter. The mutation does not interfere with the direct protein-protein interaction, but it disrupts synergistic activation of the AMH promoter by GATA4 and NR5A1. The p.Gly221Arg mutant protein also failed to bind to a known protein partner FOG2 that is essential for gonad formation. Our data demonstrate the key role of GATA4 in human testicular development.

New technologies for the identification of novel genetic markers of disorders of sex development (DSD)

Although the genetic basis of human sexual determination and differentiation has advanced considerably in recent years, the fact remains that in most subjects with disorders of sex development (DSD) the underlying genetic cause is unknown. Where pathogenic mutations have been identified, the phenotype can be highly variable, even within families, suggesting that other genetic variants are influencing the expression of the phenotype. This situation is likely to change, as more powerful and affordable tools become widely available for detailed genetic analyses. Here, we describe recent advances in comparative genomic hybridisation, sequencing by hybridisation and next generation sequencing, and we describe how these technologies will have an impact on our understanding of the genetic causes of DSD.

The quiet revolution: Disorders of sex development

The approach to the management of disorders of sex development (DSD) has undergone major changes in recent years. The catalyst has been a revised nomenclature, new classification of the causes of DSD and a willingness for health professionals to work in a multi-disciplinary format. In a remarkably short length of time, these revolutionary changes are becoming accepted practice across a range of medical and scientific disciplines.

Diagnosis of diseases of steroid hormone production, metabolism and action

Biochemical tests have been the basis for investigations of disorders affecting steroid hormones. In recent years it has been possible however to study the genes that determine functional enzymes, cofactors, receptors, transcription factors and signaling systems that are involved in the process. Analyses of mutations are available as a diagnostic service for only a few of these genes although research laboratories may be able to provide a service. Both biochemical and genetic research have brought to light new disorders. Some genes for transcription factors involved in the development of the endocrine organs have also been identified and patients with defects in these processes have been found. This paper will review general aspects of adrenal disorders with emphasis on clinical and laboratory findings. As with all endocrine investigations there are few single measurements that provide a definitive answer to a diagnosis. Timing of samples in relation to age, gender and time of day needs to be considered.