RESUMO
OBJECTIVES: To report the benefits of genetic diagnosis in patients with retinoblastoma. METHOD: Observational study. Patients with retinoblastoma and their families were included. Demographic and clinical data were recorded. Blood and tumour samples were obtained. Next generation sequencing was performed on the samples. When deletion 13 q syndrome was suspected, cytogenetics microarray was performed (Cytoscan® HD, Affymetrix, Santa Clara, CA, USA), with a high density chip of 1.9 million of non-polymorphic probes and 750 thousand SNP probes. RESULTS: Of the 7 cases were analysed 4 were male. The mean age at diagnosis was 21 months (range 5-36). Three cases had bilateral retinoblastoma, and 4 unilateral. None had family history. In all patients, blood was analysed, and a study was performed on the tissue from 2 unilateral enucleated tumours, in which 6 mutations were identified, all de novo. Just one was novel (c.164delC; case 1). One case of unilateral tumour revealed blood mosaicism, showing that his condition was inheritable, and that there is a high risk of developing retinoblastoma in the unaffected eye. The patient also has an increased risk of presenting with other primary tumours. CONCLUSION: Molecular diagnosis of RB1 in patients with retinoblastoma impacts on the decision process, costs, treatment, and prognosis of patients, as well as their families.
Assuntos
DNA de Neoplasias/genética , Neoplasias Oculares/genética , Genes do Retinoblastoma , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas de Ligação a Retinoblastoma/genética , Retinoblastoma/genética , Ubiquitina-Proteína Ligases/genética , Pré-Escolar , Chile , Deleção Cromossômica , Transtornos Cromossômicos/diagnóstico , Transtornos Cromossômicos/genética , Cromossomos Humanos Par 13/genética , Análise Mutacional de DNA , DNA de Neoplasias/sangue , DNA de Neoplasias/isolamento & purificação , Neoplasias Oculares/sangue , Neoplasias Oculares/química , Neoplasias Oculares/diagnóstico , Feminino , Humanos , Lactente , Masculino , Mosaicismo , Mutação , Neoplasias Primárias Múltiplas/sangue , Neoplasias Primárias Múltiplas/química , Neoplasias Primárias Múltiplas/diagnóstico , Neoplasias Primárias Múltiplas/genética , Polimorfismo de Nucleotídeo Único , Retinoblastoma/sangue , Retinoblastoma/química , Retinoblastoma/diagnóstico , Análise de Sequência de DNA/métodosRESUMO
INTRODUCTION: Retinoblastoma is a childhood cancer of the retina originated by altered or null retinoblastoma protein (pRb) expression. Genetic alterations in both RB1 alleles in the retinal cells are required for the development of retinoblastoma. In the sporadic form, non-hereditary RB1 gene mutations take place in a single retinoblast cell, and are therefore only present in tumor DNA (somatic mutations). Sporadic retinoblastoma is primarily unilateral, lacks family history and has no risk of transmission to descendants. Genetic tests for detection of RB1 mutation has improved the identification of carriers and facilitated accurate genetic counseling. OBJECTIVE: To identify mutations in the RB1 gene in Colombian patients with sporadic retinoblastoma by PCR-SSCP followed by sequence. MATERIALS AND METHODS: Four patients with sporadic retinoblastoma were analyzed by PCR-SSCP, followed by DNA sequencing to identify variations in the RB1 gene. RESULTS: We identified five variations in RB1 gene: three new mutations (one germline and two somatic mutations), one new polymorphism and one already reported somatic mutation. Four mutations were found in three patients with unilateral retinoblastoma and one mutation was found in a patient with bilateral retinoblastoma. One of these was a germline mutation in a sporadic unilateral retinoblastoma that was not present in the parents or three siblings analyzed. CONCLUSIONS: Our results emphasize the importance of identifying mutations for genetic counseling and clinical management of sporadic retinoblastoma patients. Description of a new RB1 gene variant is interesting since there have been a small number of polymorphisms reported for this gene.
Assuntos
Neoplasias Oculares/genética , Genes do Retinoblastoma , Mutação , Retinoblastoma/genética , Pré-Escolar , Análise Mutacional de DNA , DNA de Neoplasias/análise , DNA de Neoplasias/sangue , DNA de Neoplasias/genética , Neoplasias Oculares/sangue , Feminino , Mutação da Fase de Leitura , Mutação em Linhagem Germinativa , Humanos , Lactente , Masculino , Neoplasias Primárias Múltiplas/sangue , Neoplasias Primárias Múltiplas/genética , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Retinoblastoma/sangue , Análise de Sequência de DNARESUMO
Introduction. Retinoblastoma is a childhood cancer of the retina originated by altered or null retinoblastoma protein (pRb) expression. Genetic alterations in both RB1 alleles in the retinal cells are required for the development of retinoblastoma. In the sporadic form, non-hereditary RB1 gene mutations take place in a single retinoblast cell, and are therefore only present in tumor DNA (somatic mutations). Sporadic retinoblastoma is primarily unilateral, lacks family history and has no risk of transmission to descendants. Genetic tests for detection of RB1 mutation has improved the identification of carriers and facilitated accurate genetic counseling. Objective. To identify mutations in the RB1 gene in Colombian patients with sporadic retinoblastoma by PCR-SSCP followed by sequence. Materials and methods. Four patients with sporadic retinoblastoma were analyzed by PCR-SSCP, followed by DNA sequencing to identify variations in the RB1 gene. Results. We identified five variations in RB1 gene: three new mutations (one germline and two somatic mutations), one new polymorphism and one already reported somatic mutation. Four mutations were found in three patients with unilateral retinoblastoma and one mutation was found in a patient with bilateral retinoblastoma. One of these was a germline mutation in a sporadic unilateral retinoblastoma that was not present in the parents or three siblings analyzed. Conclusions. Our results emphasize the importance of identifying mutations for genetic counseling and clinical management of sporadic retinoblastoma patients. Description of a new RB1 gene variant is interesting since there have been a small number of polymorphisms reported for this gene.
Introducción. El retinoblastoma es un cáncer pediátrico de la retina originado por la expresión alterada o ausente de la proteína del retinoblastoma (pRb). Se requiere la alteración genética de ambos alelos RB1 en las células de la retina para el desarrollo del retinoblastoma. En la forma esporádica, las mutaciones no hereditarias del gen RB1 ocurren en un solo retinoblasto y están presentes sólo en el ADN del tumor (mutaciones somáticas). El retinoblastoma esporádico es generalmente unilateral, no tiene historia familiar y no tiene riesgo de transmisión a la descendencia. Las pruebas genéticas para la detección de mutaciones en RB1 han mejorado la identificación de portadores y han facilitado la precisión de la asesoría genética. Objetivo. Detectar mutaciones en el gen RB1 en pacientes colombianos con retinoblastoma esporádico mediante PCR-SSCP seguido de secuenciación. Materiales y métodos. Se analizaron cuatro pacientes con retinoblastoma esporádico para la detección de variaciones en el gen RB1 mediante PCR-SSCP, seguida de secuenciación. Resultados. Se identificaron cinco variaciones del gen RB1 : tres mutaciones nuevas (una de línea germinal y dos somáticas), un polimorfismo nuevo y una mutación somática ya reportada. Las cuatro mutaciones se encontraron en tres pacientes con retinoblastoma unilateral y uno con bilateral. La mutación germinal se detectó en un paciente con compromiso unilateral y no se encontró en los padres ni en los tres hermanos analizados. Conclusión. Estos resultados enfatizan la importancia, para asesoría genética y manejo clínico, de identificar mutaciones del gen RB1 en pacientes con retinoblastoma esporádico. La descripción de una nueva variante en RB1 es interesante, dado el muy bajo número de polimorfismos reportados para este gen.
Assuntos
Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Neoplasias Oculares/genética , Genes do Retinoblastoma , Mutação , Retinoblastoma/genética , Análise Mutacional de DNA , DNA de Neoplasias/análise , DNA de Neoplasias/sangue , DNA de Neoplasias/genética , Neoplasias Oculares/sangue , Mutação da Fase de Leitura , Mutação em Linhagem Germinativa , Neoplasias Primárias Múltiplas/sangue , Neoplasias Primárias Múltiplas/genética , Linhagem , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Retinoblastoma/sangue , Análise de Sequência de DNARESUMO
A peculiar case of gestational trophoblastic disease is described. A 24 year old female with former history of three molar pregnancies, spontaneous abortion and anembryoic pregnancy was admitted because of a newly diagnosed hydatiform mole (ex novo). After uterine curettage followed by a low oral dose of methotrexate (0.5 mg/kg/day) for five days. The HCG levels determined in plasma by beta-HCG- radioinmmunoassay, became negative until four months of follow3 up. An intrauterine device was installed. She resumed HCG positivity a year later and a histerectomy was performed. A post-surgical diagnosis of invasive mole was made. Since the possibility of intercurrent pregnancy was lowered by the presence of a intrauterine device, we assumed that trophoblastic transformation into an invasive mole adopted a sort of dormant period before its resurge (resurrection) independently either from curettage of chemotherapy.