Bilateral Wilms' tumor in a child with Denys-Drash syndrome: novel frameshift variant disrupts the WT1 nuclear location signaling region.

OBJECTIVES: Wilm's Tumor (WT) is the most common pediatric kidney cancer. Whereas most WTs are isolated, approximately 5% are associated with syndromes such as Denys-Drash (DDS), characterized by early onset nephropathy, disorders of sex development and predisposition to WT. CASE PRESENTATION: A 46,XY patient presenting with bilateral WT and genital ambiguity without nephropathy was heterozygous for the novel c.851_854dup variant in WT1 gene sequence. This variant affects the protein generating the frameshift p.(Ser285Argfs*14) that disrupts a nuclear localization signal (NLS) region. CONCLUSIONS: This molecular finding is compatible with the severe scenario regarding the Wilm's tumor presented by the patient even though nephropathy was absent.

WT1 Haploinsufficiency Supports Milder Renal Manifestation in Two Patients with Denys-Drash Syndrome.

Denys-Drash syndrome (DDS) is characterized by nephropathy, genital abnormalities, and predisposition to Wilms' tumor. DDS patients usually present heterozygous de novo germline WT1 mutations. The WT1 gene comprises 10 exons encoding the N-terminal transactivation and the C-terminal DNA-binding regions. Two unrelated patients with genital ambiguity and Wilms' tumor were analyzed by sequencing of the WT1 gene, and 3 mutations in exon 1 were identified of which 2 are novel. Patient 1 carried a c.555delC mutation that causes a frameshift and a premature stop codon. Patient 2 carried both c.421A>C and c.424C>T aberrations that lead to the missense p.Lys141Gln and the nonsense p.Lys142* mutation, respectively. As both patients were heterozygous for the mutations, we tested their parents who did not carry any mutation. Therefore, the 3 WT1 mutations occurred de novo in both patients. Heterozygous mutations result in WT1 haploinsufficiency as they impair protein production. They are associated with a milder DDS phenotype as observed in the patients studied here.

A novel WT1 heterozygous nonsense mutation (p.K248X) causing a mild and slightly progressive nephropathy in a 46,XY patient with Denys-Drash syndrome.

WT1 mutations have been described in a variety of syndromes, including Denys-Drash syndrome (DDS), which is characterized by predisposition to Wilms' tumor, genital abnormalities and development of early nephropathy. The most frequent WT1 defects in DDS are missense mutations located in exons 8-9. Our aim is to report a novel WT1 mutation in a 46,XY patient with a DDS variant, who presented a mild nephropathy with a late onset diagnosed during adolescence. He had ambiguous genitalia at birth. At 4 months of age he underwent nephrectomy (Wilms' tumor) followed by chemotherapy. Ambiguous genitalia were corrected and bilateral gonadectomy was performed. Sequencing of WT1 identified a novel heterozygous mutation (c.742A>T) in exon 4 that generates a premature stop codon (p.K248X). Interestingly, this patient has an unusual DDS nephropathy progression, which reinforces that patients carrying WT1 mutations should have the renal function carefully monitored due to the possibility of late-onset nephropathy.

The novel WT1 gene mutation p.H377N associated to Denys-Drash syndrome.

SUMMARY: Denys-Drash syndrome (DDS, Online Mendelian Inheritance in Man number 194080) is a rare human developmental disease generally occurring in 46,XY individuals characterized by the combination of disorder of sex development, early onset nephropathy, and Wilms' tumor (WT). DDS is mainly caused by mutations in the WT1 gene. This report describes a novel WT1 gene mutation in a DDS patient. Sequencing the WT1 gene revealed a heterozygous transversion CAT>AAT within exon 8, causing the substitution of an asparagine for a histidine at residue 377. The p.H377N mutation is predicted to diminish the WT1 protein DNA-binding affinity as it might disrupt the normal zinc finger 2 conformation.

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.

Síndrome de Denys-Drash: presentación de un caso / Denys-Drash's syndrome: a case report

El síndrome de Denys-Drash se caracteriza por pseudohemafroditismo masculino, tumor de Wilms y glomerulopatía con rápida progresión a la insuficiencia renal terminal, es producido por una mutación en el gen supresor TW1 localizado en el cromosoma 11p 13. La lesión glomerular se caracteriza por una esclerosis mesangial difusa. Reportamos un caso con genitales ambiguos, cariotipo 46 XY, síndrome nefrótico congénito a los 7 días de nacido, con rápida progresión a la insuficiencia renal terminal. Se hizo necesaria la diálisis peritoneal, y murió al mes de edad por sepsis generalizada. En el análisis del tejido renal se demuestra la esclerosis mesangial difusa(AU)

Síndrome de Denys-Drash: presentación de un caso / Denys-Drash's syndrome: a case report

El síndrome de Denys-Drash se caracteriza por pseudohemafroditismo masculino, tumor de Wilms y glomerulopatía con rápida progresión a la insuficiencia renal terminal, es producido por una mutación en el gen supresor TW1 localizado en el cromosoma 11p 13. La lesión glomerular se caracteriza por una esclerosis mesangial difusa. Reportamos un caso con genitales ambiguos, cariotipo 46 XY, síndrome nefrótico congénito a los 7 días de nacido, con rápida progresión a la insuficiencia renal terminal. Se hizo necesaria la diálisis peritoneal, y murió al mes de edad por sepsis generalizada. En el análisis del tejido renal se demuestra la esclerosis mesangial difusa

An unusual phenotype of Frasier syndrome due to IVS9 +4C>T mutation in the WT1 gene: predominantly male ambiguous genitalia and absence of gonadal dysgenesis.

The Wilms' tumor gene (WT1) encodes a zinc-finger transcription factor involved in the development of the kidneys and gonads and their subsequent normal function. Mutations in the WT1 gene were identified in patients with WAGR (Wilms' tumor, aniridria, genitourinary abnormalities, and mental retardation), Denys-Drash syndrome, and Frasier syndrome (FS). Constitutional heterozygous mutations of the WT1 gene, almost all located at intron 9, are found in patients with FS. This syndrome is characterized by female external genitalia in 46,XY patients, late renal failure, streak gonads, and high risk of gonadoblastoma development. We report a male with FS with an unusual phenotype characterized by normal penis size with perineal hypospadias, end-stage renal failure at the age of 19 yr, normal adult male serum T levels, extremely elevated gonadotropin levels, para-testicular leiomyoma, unilateral testicular germ cell tumor, bilateral gonadoblastoma, and absence of gonadal dysgenesis. Automatic sequencing identified the IVS9 +4C>T mutation in the WT1 gene, which predicts a change in splice site utilization. WT1 transcript analysis showed reversal of the normal positive/negative KTS (lysine, threonine, and serine) isoform ratio, confirming the diagnosis of FS. This patient with FS presents an external genitalia of Denys-Drash syndrome, suggesting that these two syndromes are not distinct diseases but may represent two ends of a spectrum of disorders caused by alterations in WT1 gene. This case expands the spectrum of phenotypes associated with WT1 mutations, by including predominantly male ambiguous genitalia and absence of gonadal dysgenesis, extremely high gonadotropin levels, and delayed adrenarche, and presence of a para-testicular leiomyoma, bilateral gonadoblastoma, and germ cell neoplasia.