Recurrent somatic chromosomal abnormalities in relapsed extraocular retinoblastoma

Most reports about copy number alterations (CNA) in retinoblastoma relate to patients with intraocular disease and features of children with extraocular relapse remain unknown, so we aimed to describe the CNA in this population. We evaluated 23 patients and 27 specimens from 4 centers. Seventeen cases had extraocular relapse after initial enucleation and six cases after an initial preservation attempt. We performed an analysis of CNA and BCOR gene alteration by SNP array (Single Nucleotide Polymorfism array), whole-exome sequencing, IMPACT panel and CGH array (Array-based comparative genomic hybridization). All cases presented CNA at a higher prevalence than those reported in previously published studies for intraocular cases. CNA previously reported for intraocular retinoblastoma were found at a high frequency in our cohort: gains in 1q (69.5%), 2p (60.9%) and 6p (86.9%), and 16q loss (78.2%). Other, previously less-recognized, CNA were found including loss of 11q (34.8%), gain of 17q (56.5%), loss of 19q (30.4%) and BCOR alterations were present in 72.7% of our cases. A high number of CNA including 11q deletions, 17q gains, 19q loss, and BCOR alterations, are more common in extraocular retinoblastoma. Identification of these features may be correlated with a more aggressive tumor warranting consideration for patient management.Fil: Aschero, María del Rosario. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Francis, Jasmine H.. Memorial Sloan-Kettering Cancer Center; Estados UnidosFil: Ganiewich, Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Gomez Gonzalez, Soledad. Hospital Sant Joan de Deu Barcelona; EspañaFil: Sampor, Claudia. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Zugbi, Santiago. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ottaviani, Daniela. Universite de Paris; Francia. Institute Curie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Lemelle, Lauriane. Universite de Paris; Francia. Institute Curie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Mena, Marcela Daniela C. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Winter, Ursula Andrea. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Correa Llano, Genoveva. Hospital Sant Joan de Deu Barcelona; EspañaFil: Lamas, Gabriela. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Lubieniecki, Fabiana. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Szijan, Irene. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Genética y Biología Molecular; ArgentinaFil: Mora, Jaume. Hospital Sant Joan de Deu Barcelona; EspañaFil: Podhajcer, Osvaldo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Doz, François. Universite de Paris; Francia. Institute Curie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Radvanyi, François. Universite de Paris; Francia. Institute Curie; Francia. Centre National de la Recherche Scientifique; FranciaFil: Abramson, David H.. Memorial Sloan-Kettering Cancer Center; Estados UnidosFil: Llera, Andrea Sabina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Schaiquevich, Paula Susana. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lavarino, Cinzia. Hospital Sant Joan de Deu Barcelona; EspañaFil: Chantada, Guillermo Luis. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina. Hospital Sant Joan de Deu Barcelona; España. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

RB1 gene mutations in Argentine retinoblastoma patients. Implications for genetic counseling

Retinoblastoma (RB) is an inherited childhood ocular cancer caused by mutations in the tumor suppressor RB1 gene. Identification of RB1 mutations is essential to assess the risk of developing retinoblastoma in the patients´ relatives. Retinoblastoma is a potentially curable cancer and an early diagnosis is critical for survival and eye preservation. Unilateral retinoblastoma is mostly non-heritable and results from two somatic mutations whereas bilateral retinoblastoma is heritable and results from one germline and one somatic mutation, both have high penetrance, 90%. The purpose of this study was to identify causative RB1 mutations in RB patients with different clinical presentations. A comprehensive approach was used to study a cohort of 34 patients with unilateral, bilateral and trilateral retinoblastoma. Blood and tumor DNA was analyzed by sequencing and multiplex ligation-dependent probe amplification (MLPA) assay. Validation of an insertion mutation was performed by cloning the PCR product. Most of the patients in our cohort had unilateral RB, eight patients had bilateral RB and one patient had a trilateral tumor with ocular and suprasellar/sellar locations. Other tumors in addition to retinoblastoma were also found in the affected families. One patient had two syndromes, retinoblastoma and schwannomatosis, and another RB patient had a father with a retinoma. Five out of the 25 unilateral RB patients carried germinal mutations (20%), which were mostly missense mutations. The bilateral and trilateral patients carried splice-site, nonsense and frameshift mutations as well as a whole RB1 gene deletion. Missense mutations were associated with mild phenotype: unilateral retinoblastoma, retinoma or no tumor. In this study we identified causative RB1 mutations in most bilateral RB patients and in some unilateral RB patients, including five novel mutations. These data are crucial for genetic counseling and confirm the need to perform complete genetic screening for RB1 mutations in both constitutional and tumor tissues.Fil: Parma, Diana Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Ferrer, Marcela Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Luce, Leonela Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Giliberto, Florencia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Szijan, Irene. Universidad de Buenos Aires; Argentin

Prognostic value of mutations in isocitrate dehydrogenase 1 (IDH1) and reverse telomerase transcriptase (TERT) in Argentine patients` gliomas

Background and aim: Gliomas are the most common primary brain tumors, and they are classified according to their histopathological and genetic features. Tumorigenesis depends on alterations in different genes. The aim of this study was to identify mutations in IDH1 and TERT genes in gliomas of Argentine patients and to correlate them with clinical features. Methods. DNA was isolated from 19 biopsies with different glioma grades matched with blood samples. IDH1 and TERT mutations were identified by PCR amplification and sequencing. Results. Six out of seven patients with low-grade glioma (grade II) harbor IDH1 mutations, mainly without tumor growth and an overall survival of more than 12 months. Eleven out of twelve patients with high-grade gliomas (grade III/IV) showed wild type IDH1, mainly with tumor growth and shorter survival than low-grade gliomas. Mutated TERT promoter was present in 5 out of 11 high-grade gliomas, showing the prevalence of polymorphic C allele, whereas, low-grade gliomas showed mutated TERT in 1 out of 5 gliomas and a predominance of T allele. TERT and IDH1 mutations were mutually exclusive in most gliomas. Conclusions: Our results show that genetic tests provided more accurate diagnosis than histopathological analysis. Evolution of gliomas can be predicted primarily by the mutational status of IDH1 and secondarily by other markers, such as TERT mutational status, and the patient´s age.</jats:p

Small mutation screening in the DMD gene by whole exome sequencing of an Argentine Duchenne/Becker muscular dystrophies cohort

Dystrophinopathies are neuromuscular X-linked recessive diseases caused by mutations in the DMD gene. This study aimed to identify DMD gene small mutations by Whole Exome Sequencing (WES), in order to confirm clinical diagnosis, identify candidates for Ataluren treatment and perform carrier status testing. Furthermore, was our goal to characterize the DMD sequence variants and identify ancestral haplotypes. We analyzed 40 non-related individuals (38 affected boys with dystrophinopathy presumptive clinical diagnosis and 2 at-risk women) with negative MLPA results. Pathogenic DMD variants were found in 32 boys. Surprisingly, in another 4 patients with absence/deficiency of dystrophin in muscle biopsy, pathogenic variants were found in Limb-girdle muscular dystrophy genes. Therefore, the WES detection rate resulted ∼94% (36/38). We could identify 15 Ataluren candidates and exclude 2 at-risk women. The characterization of the occurrence and diversity of DMD sequence variants from our cohort and from LOVD database, revealed no hotspots but showed exons/introns unlikely to carry small molecular alterations and exons presenting a greater mutagenic abundance than others. Also, we have detected the existence of 2 co-segregating haplotypes blocks. Finally, this work represents the first DMD gene small mutations screening applying WES in an argentine cohort, contributes with the characterization of our population and collaborates with the DMD small mutation's knowledge.Fil: Luce, Leonela Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Carcione, María Micaela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; ArgentinaFil: Mazzanti, Chiara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Ferrer, Marcela Maria. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Szijan, Irene. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; ArgentinaFil: Giliberto, Florencia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Inmunología, Genética y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Inmunología, Genética y Metabolismo; Argentin