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

Pediatric renal tumor epidemiology: Global perspectives, progress, and challenges

Pediatric renal tumors account for 3%-11% of childhood cancers, the most common of which is Wilms tumor or nephroblastoma. Epidemiology plays a key role in cancer prevention and control by describing the distribution of cancer and discovering risk factors for cancer. Large pediatric research consortium trials have led to a clearer understanding of pediatric renal tumors, identification of risk factors, and development of more risk-adapted therapies. These therapies have improved event-free and overall survival for children. However, several challenges remain and not all children have benefited from the improved outcomes. In this article, we review the global epidemiology of pediatric renal tumors, including key consortium and global studies. We identify current knowledge gaps and challenges facing both high and low middle-incomes countries.

WAGR, Sex Reversal, Bilateral Gonadoblastomas, and Intralobar Nephrogenic Rests: Uncertainties of Pre-Biopsy Chemotherapy in a High Risk Syndrome for Nephroblastoma

Background: WT1 deletions are associated with nephroblastomas, WT mutations are associated with 46, XY sex reversal. It is unclear why only a few WT1 deletions are associated with sex reversal. Case report. This 46, XY female had a 15.2 MB interstitial deletion of 11p14.1p11.2, which included WT1 and FSHB. No pathogenic abnormalities were identified in 156 other genes associated with disorders of sexual development. Bilateral gonadoblastomas were incidentally diagnosed at 17 months of age at the time of prophylactic gonadectomies. She was treated without biopsy for bilateral nephroblastomas radiologically identified at 18 months of age. Bilateral partial nephrectomies contained treated intralobular nephrogenic rests. Conclusion: It is unclear why WT1 deletions are less associated with 46, XY sex reversal than WT1 mutations. Treating suspected nephroblastomas without biopsy, even in patients with syndromes associated with bilateral nephroblastomas, may still lead to diagnostic and therapeutic uncertainties.

Pediatric renal tumor epidemiology: Global perspectives, progress, and challenges

Pediatric renal tumors account for 3%-11% of childhood cancers, the most common of which is Wilms tumor or nephroblastoma. Epidemiology plays a key role in cancer prevention and control by describing the distribution of cancer and discovering risk factors for cancer. Large pediatric research consortium trials have led to a clearer understanding of pediatric renal tumors, identification of risk factors, and development of more risk-adapted therapies. These therapies have improved event-free and overall survival for children. However, several challenges remain and not all children have benefited from the improved outcomes. In this article, we review the global epidemiology of pediatric renal tumors, including key consortium and global studies. We identify current knowledge gaps and challenges facing both high and low middle-incomes countries.

Endocrine outcome and seminal parameters in young adult men born with hypospadias: A cross-sectional cohort study

BACKGROUND

Hypospadias affects around 1/200 newborn males. Intrauterine testicular dysfunction may underlie a subset of cases. The long-term endocrine and reproductive outcomes in these men remain largely unknown.

METHODS

Cross-sectional study in Ghent and Vienna University Hospitals to assess the endocrine and seminal parameters of young adult men (16-21 years) born with non-syndromic hypospadias (NSH) (n = 193) compared to healthy typical males (n = 50). Assessments included physical exam, semen analysis, hormone assays and exome-based gene panel analysis (474 genes).

FINDINGS

All participants had experienced a spontaneous puberty, in spite of higher LH and INSL3 levels than typical males. Oligo- or azoospermia was observed in 32/172 (18·6%; 99%-CI: 12·2-27·4%) of NSH men; but in 5/16 (31·3%; 99%-CI: 11·1;62·4%) of complex NSH men and in 13/22 (59·1%; 99%-CI: 33·2-80·7%) of those born small for gestational age (SGA). No (likely) pathogenic coding variants were found in the investigated genes. Suboptimal statural growth affected 8/23 (34·8%; 99%-CI: 15·4-61·0%) of men born SGA with NSH.

INTERPRETATION

Spermatogenesis is significantly compromised in NSH men, especially in those born SGA or those with complex NSH. Long-term andrological follow-up is recommended, including end-pubertal semen analysis. No clear monogenic causes could be demonstrated in our cohort even in proximal or complex NSH. Being born SGA with NSH is frequently associated with poor catch-up growth, requiring growth hormone therapy in some.

FUNDING

Research grants from the European Society of Paediatric Endocrinology, the Belgian Society of Pediatrics, the Belgian Society of Pediatric Endocrinology and Diabetology and the Research Foundation Flanders (FWO).

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.

Spectrum of Clinical Manifestations in Children With WT1 Mutation: Case Series and Literature Review

BACKGROUND

Mutations of the Wilms tumor suppressor-1 gene (WT1) are associated with life-threatening glomerulopathy, disorders of sexual development, Wilm's tumor, and gonadal malignancies. Our objectives were to describe the clinical presentations, age of progression, and onset of complications of WT1 mutation through a case series and literature review.

METHODS

A retrospective study included all patients followed at the University of Miami/Holtz Children's Hospital from January 2000 to December 2020 with a diagnosis of WT1 mutation. A literature review of WT1 mutation cases was analyzed for clinical manifestations, karyotype, and long-term outcomes.

RESULTS

The WT1 mutation was identified in 9 children, median age at presentation of 0.9 years (range 1 week to 7 years). A total of four had female phenotypes, and 5 had abnormalities of male external genitalia, while all had XY karyotypes. All progressed to end-stage kidney disease (ESKD) and received a kidney transplant at a median age of 5 years (1.5-15 years). During a median time of follow-up of 9 years (range 2-28 years), there were 2 allograft losses after 7 and 10 years and no evidence of post-transplant malignancy. From 333 cases identified from the literature review, the majority had female phenotype 66% (219/333), but the predominant karyotype was XY (55%, 183/333). Of the female phenotypes, 32% (69/219) had XY sex reversal. Wilm's tumor occurred in 24%, predominantly in males with gonadal anomalies.

CONCLUSIONS

Early recognition of WT1 mutation is essential for comprehensive surveillance of potential malignancy, avoidance of immunosuppressants for glomerulopathy, and establishing long-term multidisciplinary management.

Exonic WT1 pathogenic variants in 46,XY DSD associated with gonadoblastoma

OBJECTIVE

The literature regarding gonadoblastoma risk in exonic Wilms' tumor suppressor gene (WT1) pathogenic variants is sparse. The aim of this study is to describe the phenotypic and genotypic characteristics of Asian-Indian patients with WT1 pathogenic variants and systematically review the literature on association of exonic WT1 pathogenic variants and gonadoblastoma.

DESIGN

Combined retrospective-prospective analysis.

METHODS

In this study, 46,XY DSD patients with WT1 pathogenic variants detected by clinical exome sequencing from a cohort of 150 index patients and their affected relatives were included. The PubMed database was searched for the literature on gonadoblastoma with exonic WT1 pathogenic variants.

RESULTS

The prevalence of WT1 pathogenic variants among 46,XY DSD index patients was 2.7% (4/150). All the four patients had atypical genitalia and cryptorchidism. None of them had Wilms' tumor till the last follow-up, whereas one patient had late-onset nephropathy. 11p13 deletion was present in one patient with aniridia. The family with p.Arg458Gln pathogenic variant had varied phenotypic spectrum of Frasier syndrome; two siblings had gonadoblastoma, one of them had growing teratoma syndrome (first to report with WT1). On literature review, of >100 exonic point pathogenic variants, only eight variants (p.Arg462Trp, p.Tyr177*, p.Arg434His, p.Met410Arg, p.Gln142*, p.Glu437Lys, p.Arg458*, and p.Arg458Gln) in WT1 were associated with gonadoblastoma in a total of 15 cases (including our two cases).

CONCLUSIONS

WT1 alterations account for 3% of 46,XY DSD patients in our cohort. 46,XY DSD patients harboring exonic WT1 pathogenic variants carry a small but definitive risk of gonadoblastoma; hence, these patients require a gonadoblastoma surveillance with a more stringent surveillance in those harboring a gonadoblastoma-associated variant.

Wilms tumour surveillance in at-risk children: Literature review and recommendations from the SIOP-Europe Host Genome Working Group and SIOP Renal Tumour Study Group

Since previous consensus-based Wilms tumour (WT) surveillance guidelines were published, novel genes and syndromes associated with WT risk have been identified, and diagnostic molecular tests for previously known syndromes have improved. In view of this, the International Society of Pediatric Oncology (SIOP)-Europe Host Genome Working Group and SIOP Renal Tumour Study Group hereby present updated WT surveillance guidelines after an extensive literature review and international consensus meetings. These guidelines are for use by clinical geneticists, pediatricians, pediatric oncologists and radiologists involved in the care of children at risk of WT. Additionally, we emphasise the need to register all patients with a cancer predisposition syndrome in national or international databases, to enable the development of better tumour risk estimates and tumour surveillance programs in the future.

New mutation in WT1 gene in a boy with an incomplete form of Denys-Drash syndrome: A CARE-compliant case report

RATIONALE

Pediatric patients with WTl-associated syndromes (including Wilms' tumor-aniridia syndrome and Denys-Drash syndrome), Perlman syndrome, mosaic aneuploidy, and Fanconi anemia with a biallelic breast cancer type 2 susceptibility protein mutation have the highest risk of developing Wilms' tumor.

PATIENT CONCERNS AND DIAGNOSIS

We describe a patient with bilateral metachronous Wilms' tumor, ambiguous genitalia characterized by 46, XY disorder of sexual development (DSD) with scrotal hypospadias and bilateral abdominal cryptorchidism, but without nephropathy. At the age of 7 months, the child underwent left nephrectomy with left orchiopexy. At follow-up after 8 months, a second tumor with a diameter of 10 mm was detected in abdominal CT scans at the lower pole of the right kidney.

INTERVENTION

Intra-operative macroscopic inspection of the right kidney revealed a tight attachment of the right proximal ureter to the tumor. Thus, retroperitoneoscopic resection of the lower pole of the right kidney had to be changed to an open surgical procedure with partial resection of the proximal ureter and high uretero-ureterostomy. We subsequently performed orchiopexy and two-stage correction of hypospadias using a free skin graft.

OUTCOMES

At the last follow-up at the age of 8 years, no pathology requiring treatment was noted. A pair-end-reading (2 × 125) DNA analysis with an average coverage of at least 70 to 100 × revealed a previously unknown heterozygous mutation in exon 7 of the Wilms' tumor suppressor gene 1 (WT1) gene (chr11:32417947G>A), leading to the appearance of a site of premature translation termination in codon 369 (p.Arg369Ter, NM_024426.4). This mutation had not been registered previously in the control samples "1000 genomes," Exome Sequencing Project 6500, and the Exome Aggregation Consortium. Thus, to the best of our knowledge this represents a newly identified mutation causing incomplete Denys-Drash syndrome.

Genetics of Azoospermia

Azoospermia affects 1% of men, and it can be due to: (i) hypothalamic-pituitary dysfunction, (ii) primary quantitative spermatogenic disturbances, (iii) urogenital duct obstruction. Known genetic factors contribute to all these categories, and genetic testing is part of the routine diagnostic workup of azoospermic men. The diagnostic yield of genetic tests in azoospermia is different in the different etiological categories, with the highest in Congenital Bilateral Absence of Vas Deferens (90%) and the lowest in Non-Obstructive Azoospermia (NOA) due to primary testicular failure (~30%). Whole-Exome Sequencing allowed the discovery of an increasing number of monogenic defects of NOA with a current list of 38 candidate genes. These genes are of potential clinical relevance for future gene panel-based screening. We classified these genes according to the associated-testicular histology underlying the NOA phenotype. The validation and the discovery of novel NOA genes will radically improve patient management. Interestingly, approximately 37% of candidate genes are shared in human male and female gonadal failure, implying that genetic counselling should be extended also to female family members of NOA patients.

Integrating clinical and genetic approaches in the diagnosis of 46,XY disorders of sex development

46,XY differences and/or disorders of sex development (DSD) are clinically and genetically heterogeneous conditions. Although complete androgen insensitivity syndrome has a strong genotype-phenotype correlation, the other types of 46,XY DSD are less well defined, and thus, the precise diagnosis is challenging. This study focused on comparing the relationship between clinical assessment and genetic findings in a cohort of well-phenotyped patients with 46,XY DSD. The study was an analysis of clinical investigations followed by genetic testing performed on 35 patients presenting to a single center. The clinical assessment included external masculinization score (EMS), endocrine profiling and radiological evaluation. Array-comparative genomic hybridization (array-CGH) and sequencing of DSD-related genes were performed. Using an integrated approach, reaching the definitive diagnosis was possible in 12 children. The correlation between clinical and genetic findings was higher in patients with a more severe phenotype (median EMS 2.5 vs 6; P = 0.04). However, in 13 children, at least one variant of uncertain significance was identified, and most times this variant did not correspond to the original clinical diagnosis. In three patients, the genetic studies guided further clinical assessment which resulted in a reclassification of initial clinical diagnosis. Furthermore, we identified eight patients harboring variants in more than one DSD genes, which was not seen in controls (2.5%; P = 0.0003). In summary, taking into account potential challenges in reaching the definitive diagnosis in 46,XY DSD, only integrated approach seems to be the best routine practice.

The genetic factors contributing to hypospadias and their clinical utility in its diagnosis

Hypospadias is among the most common congenital malformations in male neonates. It results from abnormal penile and urethral development, but is a multifactorial disorder that is highly heterogeneous, with several genetic and environmental determinants. Monogenic and chromosomal abnormalities are present in approximately 30% of cases, although the genetic factors contributing to hypospadias remain unknown in 70% of cases. While defects in androgen synthesis can lead to this malformation, mutational analyses have shown several genes, such as sonic hedgehog, fibroblast growth factors, bone morphogenetic proteins, homeobox genes, and the Wnt family, are involved in the normal development of male external genitalia. Mutations in the genes of penile development (e.g., HOX, FGF, Shh) and testicular determination (e.g., WT1, SRY), luteinizing hormone receptor, and androgen receptor have also been proposed to be implicated in hypospadias. Here we review the recent advances in this field and discuss the potential genes that could determine the risk of hypospadias.

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.

The molecular pathways underlying early gonadal development

The body of knowledge surrounding reproductive development spans the fields of genetics, anatomy, physiology and biomedicine, to build a comprehensive understanding of the later stages of reproductive development in humans and animal models. Despite this, there remains much to learn about the bi-potential progenitor structure that the ovary and testis arise from, known as the genital ridge (GR). This tissue forms relatively late in embryonic development and has the potential to form either the ovary or testis, which in turn produce hormones required for development of the rest of the reproductive tract. It is imperative that we understand the genetic networks underpinning GR development if we are to begin to understand abnormalities in the adult. This is particularly relevant in the contexts of disorders of sex development (DSDs) and infertility, two conditions that many individuals struggle with worldwide, with often no answers as to their aetiology. Here, we review what is known about the genetics of GR development. Investigating the genetic networks required for GR formation will not only contribute to our understanding of the genetic regulation of reproductive development, it may in turn open new avenues of investigation into reproductive abnormalities and later fertility issues in the adult.

Description of mutation spectrum and polymorphism of Wilms' tumor 1 (WT1) gene in hypospadias patients in the Indonesian population

INTRODUCTION

Hypospadias is one of the most common congenital anomalies of the penis. Previous studies reported mutation of the Wilms' tumor 1 (WT1) gene as a cause of hypospadias. The aim of this study is to describe the WT1 mutation spectrum and polymorphism in hypospadias patients in Indonesia.

MATERIAL AND METHODS

DNA was isolated from 74 hypospadias patients at the Division of Pediatric Surgery, Department of Surgery Hasan Sadikin Hospital. All exons in the WT1 gene were amplified by a PCR method, followed by Sanger sequencing. Mutation analysis was performed using BioEdit software and in silico analysis using Mutation Taster, Polymorphism Phenotyping-2 (PolyPhen-2), and Sorting Intolerant from Tolerant (SIFT).

RESULT

DNA analysis results showed two types of heterozygous mutations in five subjects (Table), hence the frequency of WT1 mutations was 6.7% (10/148 allele). The first mutation was a missense mutation identified in twin boys. The second was a novel heterozygous alteration in the non-coding region nine bp upstream of exon 6 (c.366-9T>C), which was identified in three patients. One heterozygous polymorphism in the coding region of exon 7 (c.471A>G/rs16754) was identified in 10 subjects. This variant did not cause any change in amino acid products (silence polymorphism). Allele frequency for the G allele (mutant allele) and A allele (wild type) was 13.5% and 86.5%, respectively.

DISCUSSION

WT1 is one of the best known hypospadias genes. The WT1 gene is involved in male genital development in the early and late periods of sex determination, and hence is known as a long-term expression gene in genitalia development. Mutation analysis of WT1 in a Chinese population identified that the WT1 mutation frequency was 4.4%. The WT1 mutation frequency identified in the present study was higher, at 6.7%. Coincidentally, research subjects with p.R158H variants were monozygotic twin siblings with midshaft hypospadias accompanied by undescended testis in one and penoscrotal hypospadia with micropenis in the other. The incidence of familial hypospadias in male siblings suffering from hypospadias was reported to be 9.6% in a study conducted by Sorensen et al. Moreover, in the present study polymorphism c.471A>G(rs16754) at exon 7 was identified heterozygously in 10 research subjects (minor allele frequency 13.5%).

CONCLUSION

WT1 mutations were identified in only a few cases of hypospadias and most of these were syndromic. This result implies that mutation of WT1 is not a common cause of hypospadias in the Indonesian population.

The Wilms' tumour 1 gene as a factor in non-syndromic hypospadias: evidence and controversy

Hypospadias is one of the most frequent congenital anomalies of the male external genitalia. Its pathogenesis is due to largely unknown or poorly understood genetic factors and is further complicated by environmental-intrauterine-risk factors. One of the genes currently in focus by molecular biologists and clinicians studying syndromic forms of hypospadias is the Wilms' tumour 1 (WT1) gene. There is controversy over whether WT1 defects are also responsible for isolated hypospadias. In this review, we briefly cover the role of WT1 as a transcription factor and discuss proposed pathogenic pathways leading to hypospadias, outlining possible directions for research. We assess available evidence on the gene's mutations and polymorphisms recently suggested in the background of the disease, and examine the putative role of WT1-associated proteins. We also review relevant aspects of genome-wide association studies carried out so far, and raise some points to consider in future efforts.

Proximal Hypospadias and a Novel WT1 Variant: When Should Genetic Testing Be Considered?

We present a case of an infant with proximal hypospadias, penoscrotal transposition, and bilaterally descended testes found to have a clinically significant WT1 gene alteration on a customized disorder of sex development genetic panel in which 62 genes associated with 46, XY disorders of sex development were evaluated. This diagnosis led to early screening for and diagnosis and treatment of Wilms tumor. Patients with proximal hypospadias are not routinely evaluated by genetic testing, and when initial hormonal analyses are within normal ranges for a typical male patient, the genital atypia is usually attributed to an isolated anatomic abnormality. There is no consensus among urologists, endocrinologists, or geneticists regarding when genetic testing is warranted in these patients or the extent of genetic testing that should be pursued. However, given advances in genetic testing and the discovery of more genetic variants, the genetic evaluation of infants with proximal hypospadias should be considered on an individual patient basis. Only with continued evaluation and the identification of further genetic variants can we establish future parameters for genetic evaluation in patients with proximal hypospadias and more appropriately counsel patients and their families regarding the implications of these variants.

Canadian Urological Association-Pediatric Urologists of Canada (CUA-PUC) guideline for the diagnosis, management, and followup of cryptorchidism

Cryptorchidism is one of the most common congenital anomalies in males, characterized by inability to palpate the testicle in the expected normal anatomical position (i.e., within its respective hemi-scrotum). It represents an abnormality of testicular descent and development associated with long-term concerns, including infertility, hypogonadism, and development of neoplasms.

Recent findings on the genetics of disorders of sex development

PURPOSE OF REVIEW

Disorders of sex development (DSD) are a diverse group of conditions affecting gonadal development, sexual differentiation, or chromosomal sex. In this review, we will discuss recent literature on the genetic causes of DSD, with a focus on novel genetic sequencing technologies, new phenotypes associated with known DSD genes, and increasing recognition of the role of genetic regulatory elements in DSD.

RECENT FINDINGS

We performed a comprehensive search of PubMed through August 2016 to identify important peer-reviewed publications from 2015 to 2016 on the topic of DSD genetics.

SUMMARY

Whole-exome sequencing was used to successfully identify genetic causes of DSD in 35% of a cohort of 46,XY patients who had not previously received a genetic diagnosis. A novel mutation in NR5A1 has been identified as a cause of 46,XX testicular and ovotesticular DSD, demonstrating a previously unappreciated role of NR5A1 in preventing testicular differentiation in 46,XX individuals. Genetic regulatory elements of SOX9 have been identified as causes of 46,XX and 46,XY DSD.

Truncating Wilms Tumor Suppressor Gene 1 Mutation in an XX Female with Adult-Onset Focal Segmental Glomerulosclerosis and Streak Ovaries: A Case Report

About 30% of children with nephrotic syndrome (NS) have inherited forms. Among them, mutations in Wilms tumor suppressor gene 1 (WT1) are a well characterized cause associated with steroid-resistant NS, Wilms tumor, and urogenital malformation in males. However, the role of WT1 mutations in adult-onset focal segmental glomerulosclerosis (FSGS) is unclear. We report the case of a 38-year-old female with FSGS. She had been diagnosed with streak ovaries during diagnostic workup for infertility. Mutational analysis identified the heterozygous mutation c.1372C>T (p.Arg458*) in WT1 and the heterozygous non-neutral polymorphism c.868G>A (p.Arg229Gln) in NPHS2. Chromosomal analysis revealed a normal 46,XX female karyotype. Our case highlights that WT1 mutations should be considered in XX females with adult-onset FSGS, especially if urogenital abnormalities are present.

Malignancy in disorders of sex development

Disorders of sex development (DSD) represent a spectrum of conditions in which chromosomal, gonadal, or anatomic sex are atypical and affect 1 in 4,500-5,000 live births. The diagnosis of DSD raises concerns of tumor risk and treatment as well as future fertility preservation. We review the current understanding of the types of gonadal tumors that arise in DSD patients as well as possible markers and treatment. The goal is to inform the members of the DSD team (urologist, endocrinologist, geneticist, psychologist) of the latest findings regarding malignancy in DSD. PubMed^® and Google Scholar^TM literature searches were performed of current and past peer-reviewed literature on DSD (intersex) regarding gonadal development and tumor formation/treatment. Relevant reviews and original research articles were examined, including cited references, and a synopsis of the data was generated. DSD patients are at increased risk for the development of testicular carcinoma in-situ (CIS) and germ cell tumors (GCT), including seminoma, non-seminoma, juvenile granulosa cell, gonadoblastoma, and dysgerminoma. Cancer risk factors include Y-chromosomal material and gonadal position, especially for streak gonads. The 46 XX DSD patients [congenital adrenal hyperplasia (CAH)] with no genetic Y-chromosomal material are not at higher risk of cancer. Post-pubertal complete androgen insensitivity syndrome (AIS) patients remain prone to tumor development if the testes remain in the abdomen. Estimates of the risk of GCT in partial AIS for untreated undescended testes may be as high as 50%. The cancer risk of scrotal testes in partial AIS is unknown. CIS occurs almost exclusively in patients with hypovirilization, most notably in AIS. Persistent Mullerian Duct Syndrome (PMDS) confers the usual cancer risk associated with cryptorchidism, but also a possible tumor risk of the Mullerian remnant. Several markers are under investigation for tumor evaluation in the DSD population beyond hCG and AFP (Oct3/4, TSPY, WT-1). The management of patients with DSD is complex and evaluation of tumor risk is aided by advances in genotyping for Y-chromosomal material not evident in traditional karyotyping. More complete genetic screening for DSD patients should increasingly become the standard of care. Developments in pathologic diagnosis will further challenge our traditional understanding of the oncologic management and surveillance of these patients. Future studies utilizing more advanced histologic examination of gonads will improve our understanding of the true incidences of malignancy in this diverse population.

Wilms' tumor in a 51-year-old patient: An extremely rare case and review of the literature

Wilms tumor or nephroblastoma is a common kidney malignant tumor in childhood, accounting for ~5% of all pediatric tumors. At present, reports on Wilms' tumor occurring in adults, particularly at ages >30 years, are extremely rare. The majority of the cases of adult Wilms' tumor are closely associated with chemotherapy. Furthermore, in rare cases, Wilms' tumor is characterized by three classic types of cells, namely blastemal, stromal and epithelial cells. We herein report a case of Wilms' tumor with three classic types of cells on histological examination in a 51 year-old male patient who had received prior chemotherapy. The patient promptly underwent radical nephrectomy and remains alive. A review of previously presented cases of adult Wilms' tumor from PubMed database was also performed.

WT1 deletion leading to severe 46,XY gonadal dysgenesis, Wilms tumor and gonadoblastoma: case report

BACKGROUND

Heterozygous missense mutations in the WT1 gene that affect the function of the wild-type allele have been identified in Denys-Drash syndrome, which is characterized by severe gonadal dysgenesis, early-onset nephropathy and a predisposition to renal and gonadal cancer. Intron 9 splice-site mutations that influence the balance between WT1 isoforms cause a nearly similar phenotype, known as Frasier syndrome. Nonsense mutations and deletions only lead to WT1 haploinsufficiency and, hence, to less severe gonadal dysgenesis and late-onset nephropathy. WT1 analysis is mandatory in 46,XY gonadal dysgenesis with renal abnormality.

PATIENT

We describe a newborn with 46,XY severe partial gonadal dysgenesis, in whom structural renal anomalies and proteinuria were excluded. Gonadectomy was performed at the age of 1 month and the microscopy was thought to be suggestive for a gonadoblastoma. At the age of 9 months, the patient presented with a bilateral Wilms tumor.

RESULTS

We found a heterozygous WT1 whole-gene deletion but no other gene defects.

CONCLUSIONS

This case description illustrates that a WT1 deletion might be associated with a more severe phenotype than previously thought. It also illustrates that, even in the absence of renal abnormality, it is recommended to test promptly for WT1 defects in 46,XY gonadal dysgenesis.

A Boolean network model of human gonadal sex determination

BACKGROUND

Gonadal sex determination (GSD) in humans is a complex biological process that takes place in early stages of embryonic development when the bipotential gonadal primordium (BGP) differentiates towards testes or ovaries. This decision is directed by one of two distinct pathways embedded in a GSD network activated in a population of coelomic epithelial cells, the Sertoli progenitor cells (SPC) and the granulosa progenitor cells (GPC). In males, the pathway is activated when the Sex-Determining Region Y (SRY) gene starts to be expressed, whereas in females the WNT4/ β-catenin pathway promotes the differentiation of the GPCs towards ovaries. The interactions and dynamics of the elements that constitute the GSD network are poorly understood, thus our group is interested in inferring the general architecture of this network as well as modeling the dynamic behavior of a set of genes associated to this process under wild-type and mutant conditions.

METHODS

We reconstructed the regulatory network of GSD with a set of genes directly associated with the process of differentiation from SPC and GPC towards Sertoli and granulosa cells, respectively. These genes are experimentally well-characterized and the effects of their deficiency have been clinically reported. We modeled this GSD network as a synchronous Boolean network model (BNM) and characterized its attractors under wild-type and mutant conditions.

RESULTS

Three attractors with a clear biological meaning were found; one of them corresponding to the currently known gene expression pattern of Sertoli cells, the second correlating to the granulosa cells and, the third resembling a disgenetic gonad.

CONCLUSIONS

The BNM of GSD that we present summarizes the experimental data on the pathways for Sertoli and granulosa establishment and sheds light on the overall behavior of a population of cells that differentiate within the developing gonad. With this model we propose a set of regulatory interactions needed to activate either the SRY or the WNT4/ β-catenin pathway as well as their downstream targets, which are critical for further sex differentiation. In addition, we observed a pattern of altered regulatory interactions and their dynamics that lead to some disorders of sex development (DSD).

46,XY Gonadal Dysgenesis due to a Homozygous Mutation in Desert Hedgehog (DHH) Identified by Exome Sequencing

BACKGROUND

46,XY disorders of sex development (DSD) comprise a heterogeneous group of congenital conditions. Mutations in a variety of genes can affect gonadal development or androgen biosynthesis/action and thereby influence the development of the internal and external genital organs.

OBJECTIVE

The objective of the study was to identify the genetic cause in two 46,XY sisters of a consanguineous family with DSD and gonadal tumor formation.

METHODS

We used a next-generation sequencing approach by exome sequencing. Electrophysiological and high-resolution ultrasound examination of peripheral nerves as well as histopathological examination of the gonads were performed.

RESULTS

We identified a novel homozygous R124Q mutation in the desert hedgehog gene (DHH), which alters a conserved residue among the three mammalian Hedgehog ligands sonic hedgehog, Indian hedgehog, and desert hedgehog. No other relevant mutations in DSD-related genes were encountered. The gonads of one patient showed partial gonadal dysgenesis with loss of Leydig cells in tubular areas with seminoma in situ and a hyperplasia of Leydig cell-like cells expressing CYP17A1 in more dysgenetic parts of the gonad. In addition, both patients suffer from a polyneuropathy. High-resolution ultrasound revealed a structural change of peripheral nerve structure that fits well to a minifascicle formation of peripheral nerves.

CONCLUSION

Mutations in DHH play a role in 46,XY gonadal dysgenesis and are associated with seminoma formation and a neuropathy with minifascicle formation. Gonadal dysgenesis in these cases may be due to impairment of Sertoli cell-Leydig cell interaction during gonadal development.

Clinical and molecular characterization of patients with heterozygous mutations in wilms tumor suppressor gene 1

BACKGROUND AND OBJECTIVES

The Wilms tumor suppressor gene 1 (WT1) plays an essential role in urogenital and kidney development. Genotype/phenotype correlations of WT1 mutations with renal function and proteinuria have been observed in world-wide cohorts with nephrotic syndrome or Wilms tumor (WT). This study analyzed mid-European patients with known constitutional heterozygous mutations in WT1, including patients without proteinuria or WT.

DESIGN, SETTING, PARTICIPANTS & MEASUREMENTS

Retrospective analysis of genotype, phenotype, and treatment of 53 patients with WT1 mutation from all pediatric nephrology centers in Germany, Austria, and Switzerland performed from 2010 to 2012.

RESULTS

Median age was 12.4 (interquartile range [IQR], 6-19) years. Forty-four of 53 (83%) patients had an exon mutation (36 missense, eight truncating), and nine of 53 (17%) had an intronic lysine-threonine-serine (KTS) splice site mutation. Fifty of 53 patients (94%) had proteinuria, which occurred at an earlier age in patients with missense mutations (0.6 [IQR, 0.1-1.5] years) than in those with truncating (9.7 [IQR, 5.7-11.9]; P<0.001) and splice site (4.0 [IQR, 2.6-6.6]; P=0.004) mutations. Thirteen of 50 (26%) were treated with steroids and remained irresponsive, while three of five partially responded to cyclosporine A. Seventy-three percent of all patients required RRT, those with missense mutations significantly earlier (at 1.1 [IQR, 0.01-9.3] years) than those with truncating mutations (16.5 [IQR, 16.5-16.8]; P<0.001) and splice site mutations (12.3 [IQR, 7.9-18.2]; P=0.002). Diffuse mesangial sclerosis was restricted to patients with missense mutations, while focal segmental sclerosis occurred in all groups. WT occurred only in patients with exon mutations (n=19). Fifty of 53 (94%) patients were karyotyped: Thirty-one (62%) had XY and 19 (38%) had XX chromosomes, and 96% of male karyotypes had urogenital malformations.

CONCLUSIONS

Type and location of WT1 mutations have predictive value for the development of proteinuria, renal insufficiency, and WT. XY karyotype was more frequent and associated with urogenital malformations in most cases.

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.

The mutational spectrum of WT1 in male infertility

PURPOSE

We evaluated the impact of WT1 mutations in isolated severe spermatogenic impairment in a population of European ancestry. WT1 was first identified as the gene responsible for Wilms tumor. It was later associated with a plethora of clinical phenotypes often accompanied by urogenital defects and male infertility. The recent finding of WT1 missense mutations in Chinese azoospermic males without major gonadal malformations broadened the phenotypic spectrum of WT1 defects and motivated this study.

MATERIALS AND METHODS

We analyzed the WT1 coding region in a cohort of 194 Portuguese patients with nonobstructive azoospermia and in 188 with severe oligozoospermia with increased depth for the exons encoding the regulatory region of the protein. We also analyzed a group of 31 infertile males with a clinical history of unilateral or bilateral cryptorchidism and 1 patient with anorchia.

RESULTS

We found 2 WT1 missense substitutions at higher frequency in patients than in controls. 1) A novel variant in exon 1 (p.Pro130Leu) that disrupted a mammalian specific polyproline stretch in the self-association domain was more frequent in azoospermia cases (0.27% vs 0.13%, p = 0.549). 2) A rare variant in a conserved residue in close proximity to the first zinc finger (pCys350Arg) was more frequent in severe oligozoospermia cases (0.80% vs 0.13%, p = 0.113).

CONCLUSIONS

Results suggest a role for rare WT1 damaging variants in severe spermatogenic failure in populations of European ancestry. Large multicenter studies are needed to fully assess the contribution of WT1 genetic alterations to male infertility in the absence of other disease phenotypes.

A novel Alu-mediated microdeletion at 11p13 removes WT1 in a patient with cryptorchidism and azoospermia

This article describes a patient with cryptorchidism and nonobstructive azoospermia presenting a novel microdeletion of approximately 1 Mb at 11p13. It was confirmed by multiplex ligation-dependent probe amplification that this heterozygous deletion spanned nine genes (WT1, EIF3M, CCDC73, PRRG4, QSER1, DEPDC7, TCP11L1, CSTF3 and HIPK3) and positioned the breakpoints within highly homologous repetitive elements. As far as is known, this is the smallest deletion as-yet described encompassing the WT1 gene and was detected only once in a total of 32 Portuguese patients with isolated uni- or bilateral cryptorchidism. These findings suggest that molecular analysis in patients with genitourinary features suggestive of WT1 impairment, namely cryptorchidism and renal abnormalities, may reveal cryptic genetic defects.

Genotype-phenotype associations in WT1 glomerulopathy

WT1 mutations cause a wide spectrum of renal and extrarenal manifestations. Here we evaluated disease prevalence, phenotype spectrum, and genotype-phenotype correlations of 61 patients with WT1-related steroid-resistant nephrotic syndrome relative to 700 WT1-negative patients, all with steroid-resistant nephrotic syndrome. WT1 patients more frequently presented with chronic kidney disease and hypertension at diagnosis and exhibited more rapid disease progression. Focal segmental glomerulosclerosis was equally prevalent in both cohorts, but diffuse mesangial sclerosis was largely specific for WT1 disease and was present in 34% of cases. Sex reversal and/or urogenital abnormalities (52%), Wilms tumor (38%), and gonadoblastoma (5%) were almost exclusive to WT1 disease. Missense substitutions affecting DNA-binding residues were associated with diffuse mesangial sclerosis (74%), early steroid-resistant nephrotic syndrome onset, and rapid progression to ESRD. Truncating mutations conferred the highest Wilms tumor risk (78%) but typically late-onset steroid-resistant nephrotic syndrome. Intronic (KTS) mutations were most likely to present as isolated steroid-resistant nephrotic syndrome (37%) with a median onset at an age of 4.5 years, focal segmental glomerulosclerosis on biopsy, and slow progression (median ESRD age 13.6 years). Thus, there is a wide range of expressivity, solid genotype-phenotype associations, and a high risk and significance of extrarenal complications in WT1-associated nephropathy. We suggest that all children with steroid-resistant nephrotic syndrome undergo WT1 gene screening.

Hypospadias and genes related to genital tubercle and early urethral development

PURPOSE

We determined whether variants in genes associated with genital tubercle (the anlage for the penis) and early urethral development were associated with hypospadias in humans.

MATERIALS AND METHODS

We examined 293 relatively common tag single nucleotide polymorphisms in BMP4, BMP7, FGF8, FGF10, FGFR2, HOXA13, HOXD13, HOXA4, HOXB6, SRY, WT1, WTAP, SHH, GLI1, GLI2 and GLI3. The analysis included 624 cases (81 mild, 319 moderate, 209 severe, 15 undetermined severity) and 844 population based nonmalformed male controls born in California from 1990 to 2003.

RESULTS

There were 28 single nucleotide polymorphisms for which any of the comparisons (ie overall or for a specific severity) had a p value of less than 0.01. The homozygous variant genotypes for 4 single nucleotide polymorphisms in BMP7 were associated with at least a twofold increased risk of hypospadias regardless of severity. Five single nucleotide polymorphisms for FGF10 were associated with threefold to fourfold increased risks, regardless of severity. For 4 of them the results were restricted to whites. For GLI1, GLI2 and GLI3 there were 12 associated single nucleotide polymorphisms but results were inconsistent by severity and race/ethnicity. For SHH 1 single nucleotide polymorphism was associated with a 2.4-fold increased risk of moderate hypospadias. For WT1 6 single nucleotide polymorphisms were associated with approximately a twofold increased risk, primarily for severe hypospadias.

CONCLUSIONS

This study provides evidence that single nucleotide polymorphisms in several genes that contribute to genital tubercle and early urethral development are associated with hypospadias risk.

Update on the management of disorders of sex development

A number of factors have contributed to a sharp increase in the number of publications related to disorders of sex development (DSD) in the past 5 years, namely: the establishment of a consensus in 2006 about nomenclature, investigations and the need to treat these patients in a multidisciplinary setting; increase of the knowledge base about genetic mechanisms of normal and abnormal sex development; critical appraisal about the timing and nature of genital surgery in patients with DSD. Herein, the authors present a comprehensive review with up-to-date data about the approach to the newborn with ambiguous genitalia as well as the diagnosis and management of the most common DSD.

Update on disorders of sex development

PURPOSE OF REVIEW

To review the recent information regarding disorders of sex development (DSD) which contribute to, as well as highlight, the need for greater understanding of genetic mutations and the dire need for specific outcome information.

RECENT FINDINGS

New information is primarily related to the identification of genetic mutations and other gene variations that impact reproductive system development. These new data add to the increasingly complex list of genes and the multigenetic effects involved in DSD. Several reviews outline the approach to diagnosis and management of the patient with DSD and the importance of a multidisciplinary team. These reviews continue to demonstrate the lack of specific guidelines for complex DSD patients for whom sex assignment is problematic.

SUMMARY

Although genetic research continues to define new and multigenetic factors involved in the development of DSD, this review of the medical literature also underscores the fact that scientific understanding remains inadequate in many areas of DSD to provide solid guidelines for approaching the more controversial questions in the DSD patient. Accordingly, the need for larger, outcome studies using subjects with verified diagnoses are needed. Optimally, these studies would account for potentially confounding differences in genetic, social, and psychological factors to help answer the pressing question facing every clinician dealing with DSD patients - what is the relationship between medical decision-making (such as sex assignment and genital surgery) and future quality of life and adaptation.