A girl with bilateral ovarian tumours: Frasier syndrome

Frasier syndrome (FS) is characterised by male pseudohermaphroditism, slowly progressing nephropathy and frequent development of gonadoblastoma. The Wilms' tumour suppressor gene (WT1 gene) plays an important role in the development of the urogenital system and the gonads. A splice mutation in intron 9 of the WT1 gene was recently described in patients with FS. We analysed the WT1 gene of a Japanese patient with male pseudohermaphroditism, steroid resistant-nephr-opathy and gonadoblastoma by the polymerase chain reaction and direct sequencing and detected a heterozygous point mutation in intron 9. CONCLUSION: analysis of the Wilms' tumour suppressor gene in a patient with Frasier syndrome by the polymerase chain reaction and direct sequencing detected a + 5G -->A transition at a position of the second alternative splice region of exon 9, important for predicting the risk of the occurrence of Wilms' tumour.     

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.     

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.     

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.     

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.     

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.     

A novel <Emphasis Type="BoldItalic">WT1</Emphasis> gene mutation in a patient with Wilms’ tumor and 46, XY gonadal dysgenesis

Denys–Drash syndrome (DDS) is a rare genetic disorder featuring the triad of Wilms' tumor, early-onset renal failure, and 46, XY disorder of sex development. DDS is usually caused by heterozygous missense mutations in the zinc-finger region of the WT1 gene. The most frequent constitutional WT1 mutations in DDS patients are missense mutations in exons 8 and 9. We present a new case of variable DDS in a child who was found to have a novel heterozygous missense mutation in exon 7 (c.905G>T) and a splicing mutation in exon 6 (IVS6-1G>T).     

WT1 mutation as a cause of 46 XY DSD and Wilm's tumour: a case report and literature review

Aim: The Wilms’ Tumour gene is thought to have tumour suppressor activity and to play an important role in nephrogenesis, genitourinary development, haematopoiesis and sex determination. WT1 mutations will impair gonadal and urinary tract development and have been demonstrated to cause syndromes of WAGR, Denys–Drash and Fraiser. Methods: To elucidate the role of constitutional mutations of WT1, in the expression of the different clinical feature, we describe a 14‐year‐9‐month nonmosaic XY sex‐reversed woman with pure gonadal dysgenesis (46, XY karyotype, completely female external genitalia, normal Mullerian ducts, absence of Wolffian ducts, streak gonads) who had right kidney removed at 7 months of age because of Wilms’ tumour and was diagnosed as secondary thrombocytopenia (Plt 60–80 × 10⁹/L) since she was 4 years old. We sequenced the genomic DNA of all the 10 exons of the WT1 in which mutations may occur in proposita. Results: A new de novo insertion mutation in the first exon was found. A ‘GCCGCCTCACTCC’ is inserted between codon 138 and 139, resulting in the creation of a stop codon and a truncated protein. Conclusion: The present data provide further evidence to support the role of WT1 in diverse cellular functions.     

Novel p53 splicing site mutation in Li‐Fraumeni‐like syndrome with osteosarcoma

We describe a 15‐year‐old girl with a novel germline p53 splice site mutation who developed an osteosarcoma. She received several cycles of chemotherapy with complete resection of the primary tumor without amputation, and has maintained remission for 18 months. Li‐Fraumeni‐like syndrome was suspected based on familial history. Sequence analysis revealed the presence of a novel germline p53 gene mutation resulting in a G to A transition at position +1 at the donor splice site of intron 6, creating a 6 amino acid insertion. This case provides interesting insight into the phenotype‐genotype correlation in LFL syndrome with a TP53 splicing mutation.     

Management of Wilms tumors in Drash and Frasier syndromes

Background

Children with WT1 gene‐related disorders such as Denys–Drash syndrome (DDS) and Frasier syndrome (FS) are at increased risk of Wilms tumor and end‐stage renal disease. We investigated whether Wilms tumors in these patients displayed a specific phenotype or behavior and whether nephron‐sparing surgery was beneficial.

Procedure

We retrospectively studied all patients with DDS, FS, or other WT1 mutations treated at our institutions between 1980 and 2007.

Results

We identified 20 patients, of whom 18 had benign or malignant tumors. Wilms tumors occurred in 15 patients, being unilateral in 10 and bilateral in 5 (20 tumors). Median age at Wilms tumor diagnosis was 9 months. No patients had metastases. According to the International Society of Pediatric Oncology Working Classification, there were 19 intermediate‐risk tumors and one high‐risk tumor; no tumor was anaplastic. In patients with nephropathy who underwent unilateral nephrectomy for Wilms tumor or nephron‐sparing surgery for bilateral Wilms tumor, mean time to dialysis was 11 or 9 months, respectively. Other tumors included three gonadoblastomas (in two patients), one retroperitoneal soft‐tissue tumor, and one transitional cell papilloma of the bladder. Two patients, both with stage I Wilms tumor, died from end‐stage renal disease‐related complications. The median follow‐up time for the 18 survivors was 136 months (range, 17–224 months).

Conclusion

Most Wilms tumors in children with WT1‐related disorders were early‐stage and intermediate‐risk tumors, with a young age at diagnosis. In patients without end‐stage renal disease, nephron‐sparing surgery should be considered for delaying the onset of renal failure. Pediatr Blood Cancer 2009;52:55–59. © 2008 Wiley‐Liss, Inc.     

Y chromosome sequences in Turner's syndrome: association with virilization and gonadoblastoma

The presence of Y chromosome fragments in patients with Turner's syndrome is known to increase the risk of gonadoblastoma and virilization. Y chromosome material is detected in up to 6% of patients with Turner's syndrome by karyotype. By DNA analysis, Y chromosome sequences have been reported in 0-60% of patients. The putative gonadoblastoma gene has been mapped to the pericentromeric region of the Y chromosome increasing the interest in studying these sequences. AIMS: 1. To determine the frequency of occult Y chromosome sequences in patients with Turner's syndrome. 2. To analyze the clinical implications of Y sequences detected by karyotype and occult Y sequences. STUDY DESIGN: Cross-sectional study of 58 patients with Turner's syndrome (30 45,X; two with structural anomalies; 26 mosaic [two of whom were 45,X/46,XY]). SRY, TSPY and DYZ3 sequences were amplified by PCR using genomic DNA from peripheral blood. RESULTS: All three Y chromosome sequences were found in one out of 56 patients whose karyotype was not suggestive of having Y chromosome material and in one patient with 45,X/46,Xr(X) karyotype. The patients with the ring chromosome and 45,X/46,XY karyotype underwent surgery and were found to have a gonadoblastoma and dysgerminoma. The four patients with Y chromosome material had non-virilized female genitalia. CONCLUSIONS: Analysis by PCR was more sensitive in detecting Y chromosome sequences than conventional karyotype. The presence of Y material was not associated with virilization. We confirmed the association of Y fragments and gonadoblastoma at an early age.     

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.     

Cytochrome P450 oxidoreductase deficiency: Rare congenital disorder leading to skeletal malformations and steroidogenic defects

Cytochrome P450 oxidoreductase (POR) deficiency (PORD) is a newly characterized disorder. PORD is caused by homozygous or compound heterozygous mutations in POR encoding an electron donor for several microsomal enzymes such as CYP21A2, CYP17A1, CYP19A1, CYP51A1, and CYP26A1‐C1. Molecular defects of PORD include a Japanese founder mutation p.R457H, as well as various missense, nonsense, frameshift, and splice‐site mutations and exonic deletions. PORD leads to unique skeletal malformations referred to as Antley–Bixler syndrome, in addition to 46,XX and 46,XY disorders of sex development, pubertal failure, adrenal dysfunction, and maternal virilization during pregnancy. Such clinical features are ascribable to impaired activities of the POR‐dependent microsomal enzymes. PORD represents one form of congenital adrenal hyperplasia, although it can occur as a congenital malformation syndrome and a disorder of sex development. Phenotypic severity of PORD is highly variable and only partly depends on the residual activity of the mutant proteins. It is possible that PORD remains undiagnosed in several patients. Detailed hormonal assessment and molecular analysis are useful for diagnosis of PORD.     

Congenital lipoid adrenal hyperplasia (a rare form of adrenal insufficiency and ambiguous genitalia) caused by a novel mutation of the steroidogenic acute regulatory protein gene

Congenital lipoid adrenal hyperplasia (lipoid CAH) is a rare autosomal recessive disorder of adrenal and gonadal steroidogenesis. It is most frequently caused by mutations in the steroidogenic acute regulatory protein (StAR) gene. Patients with lipoid CAH typically present with adrenal crisis in early infancy, and those with a 46,XY karyotype have female genitalia. However, it has been recently recognized that the phenotype can be quite variable, in that adrenal insufficiency is detected later in life and patients may have partially masculinized or even normal male genitalia. We report a patient assigned and reared as a female with a 46,XY karyotype and with a homozygous intron 2 (c.178+1G>C) splice site mutation of the StAR gene, which is a novel mutation that causes lipoid CAH. Her clinical presentation was somewhat atypical for a patient with classic lipoid CAH, marked by mild masculinization of the genitalia, detectable adrenal steroids at baseline, and ability to tolerate the stress of a surgical procedure with anesthesia without receiving glucocorticoid treatment. Conclusion: There is significant phenotypic variability among patients with lipoid CAH. While splice site mutations in the StAR gene lead to premature translational termination, resulting in truncated and non-functional proteins, there is phenotypic variability among patients with such mutations. Our patient appears to have the more atypical phenotype compared to reported patients with similar mutations. The molecular mechanism underlying this heterogeneity remains unclear.     

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.     

Case report: WT1 exon 6 truncation mutation and ambiguous genitalia in a patient with Denys-Drash syndrome

Denys-Drash syndrome is a rare genetic disorder featuring the triad of congenital nephropathy, Wilms tumor, and intersex disorders (XY under-virilization or XY female). Denys-Drash syndrome is associated with constitutional mutations in the Wilms tumor suppressor gene WT1. Unlike WAGR (Wilms tumor, aniridia, genitourinary anomalies, and mental retardation) syndrome, with its complete deletion of one copy of WT1, Denys-Drash syndrome is generally caused by a dominant-negative mutation. We present a new case of Denys-Drash syndrome in a patient initially diagnosed with XY ambiguous genitalia/partial androgen insensitivity syndrome, who was found to have a novel nonsense mutation in exon 6 leading to a stop codon and hence a truncated protein. Based on lessons learned from this patient, the diagnosis of Denys-Drash syndrome should be considered in the presence of ambiguous genitalia and partial androgen insensitivity.     

Short stature in children with an apparently normal male phenotype can be caused by 45,X/46,XY mosaicism and is susceptible to growth hormone treatment

Girls with unexplained short stature are routinely screened for the presence of Ullrich-Turner syndrome by clinical examination, laboratory tests, and karyotyping. In this study, we performed chromosomal analysis in boys to explore the role of 45,X/46,XY mosaicism for short stature in males. Short-term effects of growth hormone treatment in male 45,X/46,XY individuals were compared retrospectively to those in female patients. We report six boys with a normal-appearing male phenotype and 45,X/46,XY mosaicism, four of whom were diagnosed postnatally because of short stature. Two boys were diagnosed prenatally by amniocentesis. Five boys were short and were treated with growth hormone (0.04–0.05 mg/kg per day) in analogy to girls with Ullrich-Turner syndrome and gonadal dysgenesis. With the exception of one patient in whom treatment was initiated only at the age of 14.6 years, the male patients with 45,X/46,XY mosaicism responded to short-term growth hormone treatment similarly to females with an increasing height SDS. Conclusion:45,X/46,XY mosaicism remains undetected in some short boys because this group is not routinely karyotyped. We recommend chromosomal analysis of boys with otherwise unexplained short stature who are short for their families. Growth hormone treatment should be offered to short boys with 45,X/46,XY mosaicism and a predicted adult height below the mid-parental range within clinical trials.Abbreviations FSH follicle stimulation hormone - GH growth hormone - IGF-I insulin-like growth factor 1 - IGFBP-3 insulin-like growth factor binding protein-3 - LH luteinising hormone - MPH mid-parental height     

Discordant expression of a new <Emphasis Type="Italic">WT1</Emphasis> gene mutation in a family with monozygotic twins presenting with congenital nephrotic syndrome

Congenital nephrotic syndrome (CNS) is a heterogeneous group of diseases with different causes and prognoses. Two thirds of cases of NS in the first year of life are caused by mutations in four genes (NPHS1, NPHS2, WT1, and LAMB2). The mutation of WT1 gene can lead to Denys-Drash syndrome (DDS). We report on female monozygotic twins with CNS presenting at 7 and 8 weeks of age with anuric renal failure. Both twins were treated by peritoneal dialysis. Renal biopsy proved diffuse mesangial sclerosis. Genetic analysis detected a new heterozygote WT1 mutation R434P in both twins. One child developed a unilateral nephroblastoma. Both twins died because of complications of CNS (sepsis and extensive thrombosis of central venous system/sepsis and sudden heart failure) at ages 23 weeks/13.5 months, respectively. DNA analysis showed the same WT1 mutation in the father, who showed at his age of 41 years no clinical consequences of this mutation and no signs of DDS. In conclusion, we report the third family with monozygotic twins with DDS due to WT1 mutation. The DDS has very rapidly led to end-stage renal failure and death in both twins which is in striking contrast to the manifestation in their father.