title: Molecular diagnosis in patients with retinoblastoma: Report of a series of cases.
abstract: OBJECTIVE
  To report the benefits of genetic diagnosis in patients with retinoblastoma.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  Molecular diagnosis of RB1 in patients with retinoblastoma impacts on the decision process, costs, treatment, and prognosis of patients, as well as their families.
authors.affiliation: Departamento de Oftalmología, Hospital San Juan de Dios, Santiago, Chile; Departamento de Oftalmología, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile.
authors.forename: D
authors.initials: D
authors.lastname: Ossandón
authors.affiliation: Departamento de Oftalmología, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile. Electronic address: mario.zanolli@me.com.
authors.forename: M
authors.initials: M
authors.lastname: Zanolli
authors.affiliation: Departamento de Oftalmología, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile.
authors.forename: J P
authors.initials: JP
authors.lastname: López
authors.affiliation: Centro de Genética y Genómica, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile.
authors.forename: F
authors.initials: F
authors.lastname: Benavides
authors.affiliation: Departamento de Oncología Pediátrica (Programa PINDA), Hospital San Juan de Dios, Santiago, Chile.
authors.forename: V
authors.initials: V
authors.lastname: Pérez
authors.affiliation: Centro de Genética y Genómica, Clínica Alemana de Santiago, Facultad de Medicina, Universidad del Desarrollo, Santiago, Chile.
authors.forename: G M
authors.initials: GM
authors.lastname: Repetto
mesh_terms: D002675:Child, Preschool; D002677:Chile; D002872:Chromosome Deletion; D025063:Chromosome Disorders / Q000175:diagnosis / Q000235:genetics; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000097:blood / Q000235:genetics* / Q000302:isolation & purification; D005134:Eye Neoplasms / Q000097:blood / Q000737:chemistry / Q000175:diagnosis / Q000235:genetics*; D005260:Female; D016161:Genes, Retinoblastoma; D006801:Humans; D007223:Infant; D008297:Male; D009030:Mosaicism; D009154:Mutation; D009378:Neoplasms, Multiple Primary / Q000097:blood / Q000737:chemistry / Q000175:diagnosis / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D012175:Retinoblastoma / Q000097:blood / Q000737:chemistry / Q000175:diagnosis / Q000235:genetics*; D056286:Retinoblastoma Binding Proteins / Q000235:genetics*; D017422:Sequence Analysis, DNA / Q000379:methods; D044767:Ubiquitin-Protein Ligases / Q000235:genetics*
chemical_list: D004273:DNA, Neoplasm; C000606393:RB1 protein, human; D056286:Retinoblastoma Binding Proteins; D044767:Ubiquitin-Protein Ligases
keywords: Cariotipo molecular; Cytogenetic microarray; Estudio genético; Gen RB1; Genetic study; Ocular tumor; RB1 gen; Retinoblastoma; Tumor ocular