Bilateral gonadoblastoma with dysgerminoma and pilocytic astrocytoma with WT1 GT‐IVS9 mutation: A 46 XY phenotypic female with Frasier syndrome

Frasier syndrome is characterized by a 46 XY disorder of sex development, nephropathy, and increased risk for gonadoblastoma due to Wilms tumor 1(WT1) mutation in the donor splice site of intron‐9, resulting in the splice form +KTS. Germ cell tumors and gonadoblastomas have been reported previously in Frasier syndrome. We present the clinical, radiological, and genetic (WT1 mutation analysis) of a 46 XY phenotypic female with Frasier syndrome with bilateral gonadoblastoma with dysgerminoma who developed pilocytic astrocytoma. Pediatr Blood Cancer 2009; 53:1349–1351. © 2009 Wiley‐Liss, Inc.     

Expanding the clinical spectrum of Frasier syndrome.

Frasier syndrome is an uncommon genetic disorder featuring progressive glomerulopathy, male pseudohermaphroditism, and gonadal dysgenesis with increased risk of gonadoblastoma and malignant germ cell tumors. It is caused by mutations in the donor splice site in intron 9 of the WT1 gene. However, because of its rarity there is limited literature available on the precise spectrum and recommended treatment modalities of this syndrome. We present the clinicopathological findings in 4 patients: 3 phenotypically female adolescents presenting with proteinuria and primary amenorrhea and a 6-month-old baby girl presenting with nephrotic syndrome in whom this very unusual case of early onset was confirmed by molecular studies. The significance of early recognition of Frasier syndrome and its differentiation from Denys-Drash syndrome is reviewed and discussed. Our observation of a case presenting with early clinical manifestations, in contrast with the classical presentation in adolescence, justifies the expansion of the clinical spectrum of Frasier syndrome and contributes to the understanding and appropriate clinical management of these patients.     

Recurrence of a dysgerminoma in Frasier syndrome

Mestrallet G, Bertholet‐Thomas A, Ranchin B, Bouvier R, Frappaz D, Cochat P. Recurrence of a dysgerminoma in Frasier syndrome.
Pediatr Transplantation 2011: 15:e53–e55. © 2010 John Wiley & Sons A/S. Abstract: FS is an inherited disease characterized by male pseudohermaphroditism and glomerular involvement leading to end‐stage renal disease during adolescence or early adulthood (J Pediatr 1964:64:740). The FS phenotype in 46,XY patients consists of female external genitalia, gonadal dysgenesis, high risk of gonadoblastoma, and development of renal failure in the second decade of life. FS is caused by heterozygous mutation in intron 9 of the WT1 leading to a change in splicing that results in loss of three amino acids (+KTS isoform), thus disrupting the normal ratio of the +KTS/?KTS isoforms that is critical for proper gonadal and renal development (Nat Genet 1997:17:467; Hum Mol Genet 1998:7:709). We report on a patient followed for FS revealed by acute peritoneal syndrome because of ovarian dysgerminoma. Therapeutic options had led to an unusual course with recurrent neoplastic disease after renal transplantation.     

Frasier syndrome comes full circle: genetic studies performed in an original patient

Frasier syndrome is a relatively rare disorder associated with XY gonadal dysgenesis, gonadoblastoma, and kidney failure. In this report, we identify a classic mutation in the Wilms' tumor 1 gene in one of the original cases of Frasier syndrome reported in this Journal in 1964.     

Frasier syndrome in a pre-menarchal girl: laparoscopic resection of gonadoblastoma

Frasier syndrome (FS) is characterized by male pseudohermaphroditism, slowly progressing nephropathy, and frequent development of gonadoblastoma. These patients are, however, often diagnosed when evaluated for primary amenorrhea. We report the case of FS in a pre-menarchal girl at the age of 6 years. Ultrasound examinations were performed and were inconclusive as to the presence or size of the gonads. Diagnostic laparoscopy was performed and the presence of bilateral streak gonads was documented and a bilateral salpingo-oophorectomy was performed. The postoperative course was uneventful. Histological examination of the streak gonads confirmed the presence of gonadoblastoma. To our knowledge, this is the first case in the literature of a pre-menarchal patient diagnosed with FS and a laparoscopic bilateral gonadoblastoma resection. Laparoscopic aspects regarding safe streak gonad removal in the pediatric population have been elaborated.     

Gonadal Function in 15 Patients Associated with WT1 Gene Mutations

Denys-Drash syndrome (DDS) and Frasier syndrome (FS) are caused by mutations of the WT1 gene. These disorders are characterized by renal disease, abnormality of male sex differentiation, and Wilms’ tumor and gonadoblastoma. There have been few reports on gonadal function in a large series of patients with mutations of the WT1 gene. Here, we evaluated the relation between gonadal function and the phenotype of external genitalia in 15 Japanese patients with WT1 mutations. We confirmed three sets of information. First, if a diagnosis of DDS and FS is arrived at by genetic analysis, there are some overlaps in the phenotypes of external genitalia and renal complications. Second, the responses of serum T for the human CG (HCG) loading test coincided with the phenotype of external genitalia in both DDS and FS, except two patients. One DDS patient had male type external genitalia with a low level of serum T response, and one FS patient had complete female external genitalia despite a definite serum T response to HCG stimulation. Third, four FS patients had incomplete development of pubic hair, together with low DHEA-S levels.     

Association of partial gonadal dysgenesis, nephropathy and WT1 gene mutation without Wilms' tumor: incomplete Denys-Drash syndrome

The concurrence of ambiguous genitalia, nephropathy and predisposition to Wilms' tumor are characteristics of Denys-Drash syndrome. Some of the reported patients do not express the full spectrum of the syndrome, while the occurrence of nephropathy has become a generally accepted common feature of this syndrome. We report an infant with male pseudohermaphroditism due to partial gonadal dysgenesis and nephropathy without Wilms' tumor but with a Wilms' tumor suppressor gene (WT1) mutation. The high risk of Wilms' tumor mandates regular surveillance and the use of prophylactic bilateral nephrectomy as a treatment is not yet clear.     

A novel WT1 gene mutation associated with wilms' tumor and congenital male genitourinary malformation

WT1 is located on the short arm of human chromosome 11 and consists of 10 coding exons. Mutations of this gene have been reported to be the cause of Wilms' tumor, congenital male genitourinary malformations, and/or renal disorders. We describe here a novel WT1 gene mutation, i.e. a point mutation at intron 7 (+2) in both the tumor and the germline cells of a patient with Wilms' tumor and congenital male genitourinary malformation, but without renal disorder. The position of the mutation is at a splice donor site of intron 7, which causes the splicing out of exon 7 and generates a truncated protein. This type of mutation in the WT1 zinc finger domain has not been reported before. The mutation is of paternal origin and is heterozygous in the germline cells. In the tumor cells, however, the maternal allele is largely lost, from 11p12 to 11p15, which results in maternal loss of heterozygosity. These results, together with the data from previous reports, suggest that WT1 may function in gonadogenesis, nephrogenesis, and Wilms' tumor tumorigenesis.     

伴皮层下囊肿的巨脑性白质脑病一家系MLC1基因突变分析

收集伴皮层下囊肿的巨脑性白质脑病(MLC)先证者及其父母的临床资料,采用聚合酶链反应和DNA 直接测序法进行MLC1 基因突变检测。患儿临床表现为运动发育迟缓、巨颅,头颅MRI 扫描显示弥漫性脑白质肿胀,伴双侧额顶部皮层下囊肿。基因测序结果发现患儿携带MLC1 基因2 个杂合突变:第3 外显子的错义突变c.217G>A(p.Gly73Arg)和第9 内含子的剪接位点突变c.772-1G>C in IVS9-1。患儿的父母均为c.772-1G>C in IVS9-1 杂合突变携带者,无临床症状。可推测患儿c.772-1G>C in IVS9-1 突变来源于父母;c.217G>A(p.Gly73Arg)为新生突变,为国内外首次报道。     

WT1 gene mutations in three girls with nephrotic syndrome

Denys-Drash syndrome and Frasier syndrome are two related conditions caused by mutations of the Wilms tumor gene, WT1. Both syndromes are characterized by male pseudohermaphrodism, a progressive glomerulopathy, and the development of genitourinary tumors. This study examines three girls with steroid-resistant nephrotic syndrome related to mutations in the WT1 gene, but with normal 46, XX karyotype and normal female phenotype. WT1 mutation analysis should be routinely done in females with steroid-resistant nephrotic syndrome.     

Broad and unexpected phenotypic expression in Greek children with steroid-resistant nephrotic syndrome due to mutations in the Wilms’ tumor 1 (<Emphasis Type="Italic">WT1</Emphasis>) gene

Mutations in the Wilms’ tumor suppressor gene 1 (WT1), most commonly within exons 8 or 9 or intron 9, are found in cases with the overlapping conditions of Denys–Drash and Frasier syndromes, as well as in patients with steroid-resistant nephrotic syndrome (SRNS). This study investigated the presence of WT1 gene mutations in cases with childhood SRNS, along with an evaluation of their clinical outcome. Twenty-seven Greek children with sporadic (19 cases) and familial (8 cases) SRNS were tested. Four phenotypically female patients with sporadic SRNS were found to carry de novo WT1 mutations, including two cases with p.R394W, and one case each with p.R366H, or n.1228+5G>A. Karyotype analysis found 46XX in three cases, but 46XY in one. No phenotype–genotype correlations were apparent in the WT1 gene positive cases since their clinical presentation varied broadly. Interestingly, one patient with a pathological WT1 nucleotide variation responded fully to combined therapy with cyclosporine A and corticosteroids. This study further illustrates that investigation of WT1 gene mutations is clinically useful to support definitive diagnosis in children presenting with SRNS in order to direct the most appropriate clinical management.     

5alpha-reductase 2 gene mutations in three unrelated patients of Greek Cypriot origin: identification of an ancestral founder effect

INTRODUCTION: 5alpha-Steroid reductase deficiency (5alphaSRD) is an autosomal recessive enzymatic deficiency. Mutations in the 5alpha-steroid reductase type 2 gene (SRD5A2) result in male pseudohermaphroditism caused by decreased dihydrotestosterone (DHT) synthesis--a key hormone of virilization of male external genitalia. AIM: To study for the first time patients from the Greek Cypriot population, describe their clinical characteristics, and identify the genetic mutations of the SRD5A2 gene. PATIENTS AND METHODS: Three unrelated patients with 46,XY karyotype born with ambiguous genitalia were examined. Patient 1 was raised as a girl and was diagnosed with partial androgen insensitivity syndrome, based on the clinical picture and incomplete laboratory investigation at the age of 4 years, and underwent gonadectomy. For this patient sequencing analysis of all five exons of the SRD5A2 gene and exons 2 to 8 of the androgen receptor (AR) gene was performed. Patients 2 and 3 were also born with ambiguous genitalia. The hCG test for these two patients was informative of 5alphaSRD, as it showed elevated T/DHT ratio after stimulation. Despite genetic counseling, both families decided to raise their infants as females because of severe under-virilization. Sequencing of the SRD5A2 gene was also completed for both patients. RESULTS: No mutations were found in the AR sequence for patient 1. Patients 1 and 3 were found homozygous for the mutation A/G at splice junction intron 1/exon 2 and patient 2 was found heterozygous for the same A/G substitution and also heterozygous for an additional mutation, Pro181Leu, in exon 3. CONCLUSIONS: The same mutation in the SRD5A2 gene was identified in three unrelated patients, in both homozygous and heterozygous form. This splice mutation was previously reported in Turkish patients. This underlying genetic abnormality may be characteristic for the Eastern Mediterranean region and is likely due to an ancestor effect.     

A familial WT1 mutation associated with incomplete Denys–Drash syndrome

Denys–Drash syndrome (DDS) is a rare disorder characterized by nephropathy, male pseudohermaphroditism, and wilms tumor. Cases are thought to arise sporadically through a de novo mutation in the wilms tumor suppressor gene (WT1), which encodes a zinc finger protein that not only acts as a tumor suppressor but is essential for normal gonadogenesis, nephrogenesis, and development of the urogenital tract. In this report, we describe a family with the well-known missense mutation in exon 9 of the WT1 gene, 1180C>T (R394W), causing incomplete DDS and no symptoms in their father. The proband, a boy with 46, XY karyotype, was born with ambiguous genitalia, penoscrotal hypospadias, and bilateral inguinal hernias. At 2 years of age, he has proteinuria and diffuse mesangial sclerosis, but no wilms tumor has been detected. The elder sister of the proband, at 3 years of age, has normal genitalia, proteinuria, focal mesangial sclerosis but no wilms tumor. The WT1 mutation was detected in both patients, who have suspected DDS, and their father, who is phenotypically normal. Conclusion: This case is unusual in that the 1180C>T mutation, which has been found in approximately 50 % of patients with complete DDS, has been inherited and is causing mild or no symptoms of DDS.     

A child with isolated nephrotic syndrome and WT1 mutation presenting as a 46, XY phenotypic male

Mutations in the WT1 gene can lead to Denys-Drash syndrome or Frasier syndrome and can also cause isolated nephrotic syndrome (NS). Most patients with isolated NS caused by WT1 mutations present as 46, XX phenotypic females. There have been two cases with an onset age younger than 3 years with isolated NS caused by WT1 mutations presenting as 46, XY phenotypic males. We present a 46, XY phenotypic male patient with isolated NS and end-stage renal disease (ESRD) at the age of 6.3 years. He had normal male external genitalia with normal penis length and soft and normal volume of both testes. A mutation, 1051A>G (K351E), in exon 8 of WT1 was identified in the patient. After starting hemodialysis, manifestations of hypertension and renal failure improved, but he died at 6.8 years of age as a result of respiratory failure and heart failure. Our study supports the necessity of searching for mutations in WT1 in 46, XY phenotypic male patients with isolated NS and ESRD.     

激素耐药型肾病综合征单卵孪生姐妹WT1基因突变

目的分析1个汉族激素耐药型肾病综合征(SRNS)家系WT1基因突变及其特点。方法研究对象为1个汉族SRNS家系先证者及其单卵孪生姐姐、父母和大姐;健康对照人群为50例尿检正常的汉族成年人。取所有研究对象外周静脉血3 mL,提取基因组DNA,PCR扩增WT1基因全部10个外显子及其周围的部分内含子序列,对PCR产物直接进行DNA序列测定。结果先证者患儿临床表型为不完全型Denys-Drash综合征,其孪生姐姐临床表型为孤立性SRNS。在该对单卵孪生姐妹中均检测到WT1基因1180C>T(R394W)杂合突变,在先证者父母及其大姐和50例健康对照人群未检测到该突变;此外,还在对该孪生姐妹检测到3个相同的WT1基因多态性——126C>T、903A>G和IVS7-32C>A。结论本研究在1个汉族SRNS家系临床表型不同的单卵孪生姐妹中发现了相同的WT1基因R394W杂合突变。     

Bilateral Wilms tumor in a boy with severe hypospadias and cryptochidism due to a heterozygous mutation in the WT1 gene

Mutations in the WT1 gene causing Wilms tumors were first reported in WAGR syndrome (Wilms tumor, Aniridia, Genitourinary malformation, mental Retardation) and Denys Drash syndrome (pseudohermaphroditism, Wilms tumor, nephropathy), but only in a few patients with hypospadias and cryptorchidism without other signs of Denys Drash (DDS) or WAGR syndrome WT1 mutations were identified. We report a boy, who was born in 1989 with hypospadias and bilateral cryptorchidism. Previous karyotyping and endocrine studies had ruled out any known cause of male pseudohermaphroditism. Subsequently, he developed a bilateral Wilms tumor, which was detected by palpation at the age of 15 months during a routine visit by the general pediatrician. Because of its extensive size, surgery and chemotherapy were needed for treatment. Analysis of the WT1 gene was performed 5 y after diagnosis and revealed a C to T transition in one allele generating a stop codon at codon 362 and subsequently leading to a truncated protein with loss of its ability to bind to DNA. No signs of DDS or WAGR syndrome are present in the boy. The work up of this patient and the so far known few comparable cases from the literature lead to the conclusion that in newborns with severe urogenital malformations not due to known chromosomal or endocrine disorders mutational screening of the WT1 gene should be performed, to evaluate the high risk of developing a Wilms tumor. We favor mutational screening in these patients as an easy tool for investigation, because in the future it will probably decrease the necessity of frequent control visits in patients without a WT1 mutation.     

Mutations in the Wilms' tumor 1 gene cause isolated steroid resistant nephrotic syndrome and occur in exons 8 and 9

Primary steroid-resistant nephrotic syndrome (SRNS) is characterized by childhood onset of proteinuria and progression to end-stage renal disease. Approximately 10-25% of familial and sporadic cases are caused by mutations in NPHS2 (podocin). Mutations in exons 8 and 9 of the WT1 gene have been found in patients with isolated SRNS and in SRNS associated with Wilms' tumor (WT) or urogenital malformations. However, no large studies have been performed to date to examine whether WT1 mutations in isolated SRNS are restricted to exons 8 and 9. To address this question, we screened a worldwide cohort of 164 cases of sporadic SRNS for mutations in all 10 exons of the WT1 gene by multiplex capillary heteroduplex analysis and direct sequencing. NPHS2 mutations had been excluded by direct sequencing. Fifteen patients exhibited seven different mutations exclusively in exons 8 and 9 of WT1. Although it is possible that pathogenic mutations of WT1 may also reside in the introns, regions of the gene that were not able to be screened in this study, these data together with our previous results (Ruf et al.: Kidney Int 66: 564-570, 2004) indicate that screening of WT1 exons 8 and 9 in patients with sporadic SRNS is sufficient to detect pathogenic WT1 mutations and may open inroads into differential therapy of SRNS.     

Tumors of Bilateral Streak Gonads in Patients with Disorders of Sex Development Containing Y Chromosome Material

The presence of Y chromosome material in patients with disorders of sex development (DSD) has been associated with a high risk of gonadoblastoma. Therefore, gonadectomy is recommended in females with bilateral streak gonads and Y chromosome material. The aim of this study was to present our experience with prophylactic gonadectomy in those patients and evaluate their risk of gonadal tumors. We reviewed the charts of 11 female patients who had bilateral gonadectomy (by laparoscopically in 9 patients, by laparotomy in 2 patients) between 1991 and 2012 at our hospital. Seven patients with Turner syndrome (TS) who carry a Y mosaic karyotype in peripheral blood, 3 patients with Swyer syndrome and one patient with Frasier syndrome were included. All patients had an unambiguous female phenotype. Age at surgery and follow-up ranged from 2 to 23 (mean 11) and 0.5 to 20 (mean 8) yr, respectively. Pathologic examination revealed gonadal tumors in 6 of 11 patients (56%), including 4 with TS, the youngest of which was 2 yr old, one with Swyer syndrome and one with Frasier syndrome. A gonadoblastoma was detected in 8 gonads, and an association of dysgerminoma with gonadoblastoma was detected in 2 gonads. Imaging studies showed no metastasis, and the postoperative course was uneventful in all patients. In our series of DSD patients with bilateral streak gonads and Y chromosome material, the risk of gonadal tumor was high. Considering the early occurrence of gonadoblastoma and its high potential for malignant transformation, early prophylactic gonadectomy is strongly recommended.     

儿童肾母细胞瘤WT1基因突变四例报道

目的 研究儿童肾母细胞瘤患者WT1基因的突变类型及突变频率.方法应用聚合酶链反应(PCR)扩增出54例儿童肾母细胞瘤患者WT1基因全部10个外显子及其相邻内含子序列,经纯化后进行PCR产物直接测序.结果 4例患者WT1基因分别存在3个杂合无义突变及1个纯合错义突变.例1患者WT1基因7号外显子第1006位碱基A→T杂合突变,造成第336号氨基酸由赖氨酸转变为终止密码子,即K336X.例2患者WT1基因9号外显子第1168位碱基c→T杂合突变,造成第390号氨基酸由精氨酸转变为终止密码子,即R390X.例3患者WT1基因6号外显子第814位碱基G→T杂合突变,造成第272号氨基酸由谷氨酸转变为终止密码子,即E272X.例4患者WT1基因10号外显子第1228位碱基A→G纯合突变,造成第410号氨基酸由丝氨酸转变为甘氨酸,即S410G.结论 散发的中国儿童肾母细胞瘤患者WT1基因外显子突变的发生率与国外报道相近,检测到的4例突变患者中3例为无义突变、1例为错义突变.