GUILHERME LOPES YAMAMOTO
Projetos de Pesquisa
Unidades Organizacionais
Instituto da Criança, Hospital das Clínicas, Faculdade de Medicina - Médico
LIM/36 - Laboratório de Pediatria Clínica, Hospital das Clínicas, Faculdade de Medicina
LIM/36 - Laboratório de Pediatria Clínica, Hospital das Clínicas, Faculdade de Medicina
6 resultados
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- Rare variants in SOS2 and LZTR1 are associated with Noonan syndrome(2015) YAMAMOTO, Guilherme Lopes; AGUENA, Meire; GOS, Monika; HUNG, Christina; PILCH, Jacek; FAHIMINIYA, Somayyeh; ABRAMOWICZ, Anna; CRISTIAN, Ingrid; BUSCARILLI, Michelle; NASLAVSKY, Michel Satya; MALAQUIAS, Alexsandra C.; ZATZ, Mayana; BODAMER, Olaf; MAJEWSKI, Jacek; JORGE, Alexander A. L.; PEREIRA, Alexandre C.; KIM, Chong Ae; PASSOS-BUENO, Maria Rita; BERTOLA, Debora RomeoBackground Noonan syndrome is an autosomal dominant, multisystemic disorder caused by dysregulation of the RAS/mitogen activated protein kinase (MAPK) pathway. Heterozygous, pathogenic variants in 11 known genes account for approximately 80% of cases. The identification of novel genes associated with Noonan syndrome has become increasingly challenging, since they might be responsible for very small fractions of the cases. Methods A cohort of 50 Brazilian probands negative for pathogenic variants in the known genes associated with Noonan syndrome was tested through whole-exome sequencing along with the relatives in the familial cases. Families from the USA and Poland with mutations in the newly identified genes were included subsequently. Results We identified rare, segregating or de novo missense variants in SOS2 and LZTR1 in 4% and 8%, respectively, of the 50 Brazilian probands. SOS2 and LZTR1 variants were also found to segregate in one American and one Polish family. Notably, SOS2 variants were identified in patients with marked ectodermal involvement, similar to patients with SOS1 mutations. Conclusions We identified two novel genes, SOS2 and LZTR1, associated with Noonan syndrome, thereby expanding the molecular spectrum of RASopathies. Mutations in these genes are responsible for approximately 3% of all patients with Noonan syndrome. While SOS2 is a natural candidate, because of its homology with SOS1, the functional role of LZTR1 in the RAS/MAPK pathway is not known, and it could not have been identified without the large pedigrees. Additional functional studies are needed to elucidate the role of LZTR1 in RAS/MAPK signalling and in the pathogenesis of Noonan syndrome.
conferenceObject Camurati-Engelmann Disease: Evaluation of a New Therapeutic Option in Two Patients(2015) PRESTI, P. de Figueiredo; MENEZES FILHO, H. Cabral; FERREIRA, M. Rodrigues; DICHTCHEKENIAN, V; SETIAN, N.; BERTOLA, R. D.; TESTAI, L. de Cassia; YAMAMOTO, G. Lopes; BARBOSA, S. Maria de Macedo; BOBOLI, I; OFASTRINI, R. Tiviana Verardo; DAMIANI, D.- Intragenic Deletion in the LIFR Gene in a Long-Term Survivor with Stuve-Wiedemann Syndrome(2015) MARQUES, Julia Hatagami; YAMAMOTO, Guilherme Lopes; TESTAI, Larissa de Cassia; PEREIRA, Alexandre da Costa; KIM, Chong Ae; PASSOS-BUENO, Maria R.; BERTOLA, Debora RomeoStuve-Wiedemann syndrome (SWS, OMIM 601559) is a rare autosomal recessive bent-bone dysplasia, caused by loss-offunction mutations in the leukemia inhibitory factor receptor (LIFR) gene, which usually leads to early death. Only few patients with long-term survival have been described in the literature. We report on a 5-year-old boy from a consanguineous marriage with molecular analysis for the LIFR gene. Sanger and next-generation sequencing (NGS) of LIFR were performed. Copy number variation analysis with NGS showed a novel mutation as the cause for the syndrome: an intragenic homozygous deletion in LIFR, involving exons 1520. Bridging PCR was carried out to confirm the intragenic deletion. This is the first description of a large deletion in LIFR, broadening the spectrum of mutations in SWS. Besides the reported allelic heterogeneity, further studies such as exome sequencing are required to identify a novel gene in order to confirm the locus heterogeneity in SWS. (C) 2015 S. Karger AG, Basel
- Schinzel-Giedion Syndrome in Two Brazilian Patients: Report of a Novel Mutation in SETBP1 and Literature Review of the Clinical Features(2015) CARVALHO, Ellaine; HONJO, Rachel; MAGALHAES, Monize; YAMAMOTO, Guilherme; ROCHA, Katia; NASLAVSKY, Michel; ZATZ, Mayana; PASSOS-BUENO, Maria Rita; KIM, Chong; BERTOLA, DeboraSchinzel-Giedion syndrome is a rare autosomal dominant disorder comprising postnatal growth failure, profound developmental delay, seizures, facial dysmorphisms, genitourinary, skeletal, neurological, and cardiac defects. It was recently revealed that Schinzel-Giedion syndrome is caused by de novo mutations in SETBP1, but there are few reports of this syndrome with molecular confirmation. We describe two unrelated Brazilian patients with Schinzel-Giedion syndrome, one of them carrying a novel mutation. We also present a review of clinical manifestations of the syndrome, comparing our cases to patients reported in literature emphasizing the importance of the facial gestalt associated with neurological involvement for diagnostic suspicion of this syndrome. (c) 2015 Wiley Periodicals, Inc.
- Comprehensive assessment of the disputed RET Y791F variant shows no association with medullary thyroid carcinoma susceptibility(2015) TOLEDO, Rodrigo A.; HATAKANA, Roxanne; LOURENCO JR., Delmar M.; LINDSEY, Susan C.; CAMACHO, Cleber P.; ALMEIDA, Marcio; LIMA JR., Jose V.; SEKIYA, Tomoko; GARRALDA, Elena; NASLAVSKY, Michel S.; YAMAMOTO, Guilherme L.; LAZAR, Monize; MEIRELLES, Osorio; SOBREIRA, Tiago J. P.; LEBRAO, Maria Lucia; DUARTE, Yeda A. O.; BLANGERO, John; ZATZ, Mayana; CERUTTI, Janete M.; MACIEL, Rui M. B.; TOLEDO, Sergio P. A.Accurate interpretation of germline mutations of the rearranged during transfection (RET) proto-oncogene is vital for the proper recommendation of preventive thyroidectomy in medullary thyroid carcinoma (MTC)-prone carriers. To gain information regarding the most disputed variant of RET, ATA-A Y791F, we sequenced blood DNA samples from a cohort of 2904 cancer-free elderly individuals (1261 via Sanger sequencing and 1643 via whole-exome/genome sequencing). We also accessed the exome sequences of an additional 8069 individuals from non-cancer-related laboratories and public databanks as well as genetic results from the Catalogue of Somatic Mutations in Cancer (COSMIC) project. The mean allelic frequency observed in the controls was 0.0031, with higher occurrences in Central European populations (0.006/0.008). The prevalence of RET Y791F in the control databases was extremely high compared with the 40 known RET pathogenic mutations (P=0.00003), while no somatic occurrence has been reported in tumours. In this study, we report new, unrelated Brazilian individuals with germline RET Y791F-only: two tumour-free elderly controls; two individuals with sporadic MTC whose Y791F-carrying relatives did not show any evidence of tumours; and a 74-year-old phaeochromocytoma patient without MTC. Furthermore, we showed that the co-occurrence of Y791F with the strong RET C634Y mutation explains the aggressive MTC phenotypes observed in a large affected family that was initially reported as Y791F-only. Our literature review revealed that limited analyses have led to the misclassification of RET Y791F as a probable pathogenic variant and, consequently, to the occurrence of unnecessary thyroidectomies. The current study will have a substantial clinical influence, as it reveals, in a comprehensive manner, that RET Y791F only shows no association with MTC susceptibility.
- Mutations in LONP1, a Mitochondrial Matrix Protease, Cause CODAS Syndrome(2015) DIKOGLU, Esra; ALFAIZ, Ali; GORNA, Maria; BERTOLA, Deborah; CHAE, Jong Hee; CHO, Tae-Joon; DERBENT, Murat; ALANAY, Yasemin; GURAN, Tulay; KIM, Ok-Hwa; LLERENAR JR., Juan C.; YAMAMOTO, Guillerme; SUPERTI-FURGA, Giulio; REYMOND, Alexandre; XENARIOS, Ioannis; STEVENSON, Brian; CAMPOS-XAVIER, Belinda; BONAFE, Luisa; SUPERTI-FURGA, Andrea; UNGER, SheilaCerebral, ocular, dental, auricular, skeletal anomalies (CODAS) syndrome (MIM 600373) was first described and named by Shehib et al, in 1991 in a single patient. The anomalies referred to in the acronym are as follows: cerebral-developmental delay, ocular-cataracts, dental-aberrant cusp morphology and delayed eruption, auricular-malformations of the external ear, and skeletal-spondyloepiphyseal dysplasia. This distinctive constellation of anatomical findings should allow easy recognition but despite this only four apparently sporadic patients have been reported in the last 20 years indicating that the full phenotype is indeed very rare with perhaps milder or a typical presentations that are allelic but without sufficient phenotypic resemblance to permit clinical diagnosis. We performed exome sequencing in three patients (an isolated case and a brother and sister sib pair) with classical features of CODAS. Sanger sequencing was used to confirm results as well as for mutation discovery in a further four unrelated patients ascertained via their skeletal features. Compound heterozygous or homozygous mutations in LONP1 were found in all (8 separate mutations; 6 missense, 1 nonsense, 1 small in-frame deletion) thus establishing the genetic basis of CODAS and the pattern of inheritance (autosomal recessive). LONP1 encodes an enzyme of bacterial ancestry that participates in protein turnover within the mitochondrial matrix. The mutations cluster at the ATP-binding and proteolytic domains of the enzyme. Biallelic inheritance and clustering of mutations confirm dysfunction of LONP1 activity as the molecular basis of CODAS but the pathogenesis remains to be explored. (C) 2015 Wiley Periodicals, Inc.