RESUMO
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.
Assuntos
Síndrome de Denys-Drash , Neoplasias Renais , Tumor de Wilms , Criança , Síndrome de Denys-Drash/genética , Síndrome de Denys-Drash/patologia , Genes do Tumor de Wilms , Heterozigoto , Humanos , Neoplasias Renais/genética , Proteínas WT1/genética , Tumor de Wilms/genéticaRESUMO
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.
Assuntos
Códon sem Sentido , Síndrome de Denys-Drash/genética , Genes do Tumor de Wilms , Nefropatias/genética , Proteínas WT1/genética , Sequência de Bases , Síndrome de Denys-Drash/etiologia , Síndrome de Denys-Drash/patologia , Heterozigoto , Humanos , Lactente , Recém-Nascido , Nefropatias/complicações , Masculino , Tumor de Wilms/genética , Adulto JovemRESUMO
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.