976 resultados para KRAS GENE MUTATION
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Defeito congênito ou malformação congênita é qualquer anomalia anatômica, metabólica ou funcional, herdada por um mecanismo de transmissão mendeliana, ou causada por uma mutação gênica nova, por uma alteração cromossômica ou por uma agressão física, química ou infecciosa sobre o feto ou embrião em desenvolvimento. Suas causas podem ser genéticas ou ambientais, sendo, na maioria das vezes, de origem multifatorial, onde fatores de predisposição genética interagem com fatores ambientais desencadeadores. No estado do Pará, um grande número de indivíduos acometidos por Fissuras Labiopalatinas são oriundos de zonas rurais, principalmente no nordeste do estado onde sabidamente se faz uso indiscriminado de agrotóxicos nocivos a saúde humana, muitos dos quais tem alto potências teratogênico .O objetivo de nosso estudo foi Investigar a associação entre o polimorfismo (rs4630) no gene GSTT1 e a exposição a agrotóxicos na etiologia das fissuras lábio palatinas, bem como analisar o padrão das alterações de fala dos pacientes de acordo com o tipo da fissura . Foram analisados 83 pacientes portadores de Fissuras Palatinas, labiais ou Labiopalatinas de ambos os sexos, e 83 mães desses pacientes, todos oriundos do estado do Pará, com residência em zona rural e capital. Foram realizadas análises fonoaudiológicas e com o sangue desses indivíduos foi feita a análise molecular. A análise estatística foi realizada através dos programas estatísticos SPSS v. 12.0 e BioEstat v. 5.0. Os testes realizados foram os testes de Regressão Logística Multipla, teste x2e o teste exato de Fisher. O resultado consiste em cinco análises moleculares diferentes. Constatamos que a presença do alelo C no genótipo dos indivíduos pode influenciar no metabolismo de xenobióticos e aumentar o risco para desenvolver fissuras Orais.
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A deficiência auditiva afeta cerca de 1 em cada 1000 recém-nascidos. Mutações no gene da conexina 26 (GJB2) são as causas mais frequentes de surdez não sindrômica em diferentes populações e é sabido que a mutação delGJB6-D13S1830 em DFNB30 é causadora de surdez neurossensorial. Muitos estudos descrevem o envolvimento de mutações no gene GJB2 com a deficiência auditiva em diferentes populações. Entretanto, existe pouca informação sobre a surdez genética no Brasil, especialmente na região Amazônica. OBJETIVO: Determinar a prevalência de mutações no gene GJB2 e da mutação delGJB6-D13S1830 em 77 casos esporádicos de surdez não sindrômicas. MÉTODO: A região codificante do gene GJB2 foi sequenciada e a PCR foi realizada para detectar a mutação delGJB6-D13S1830. RESULTADOS: O alelo 35delG foi encontrado em 9% dos pacientes (7/77). As mutações M34T e V95M foram detectadas em dois distintos pacientes heterozigotos. A mutação não patogênica V27I foi detectada em 28,6% (22/77). Não foi detectada a mutação delGJB6-D13S1830 em nenhum paciente estudado. CONCLUSÃO: Alelos mutantes no gene GJB2 foram observados em 40% (31/77) da amostra. Variantes patogênicas foram detectadas em apenas 12% (9/77). Mais estudos são necessários para elucidar causas genéticas de deficiência auditiva em populações miscigenadas.
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O objetivo desta comunicação foi descrever a detecção de coexistência de variantes HIV-1 com inserções de dois aminoácidos entre os códons 69 e 70 da transcriptase reversa. Tais variantes foram isoladas de paciente do sexo masculino, 16 anos de idade, em tratamento no interior do estado de São Paulo. Após confirmação de falha terapêutica, foi realizado teste de resistência a antirretrovirais, a partir do qual foram detectadas duas variantes contendo inserções dos aminoácidos Ser-Gly/Ser-Ala no códon 69 da transcriptase reversa, além da mutação T69S. Tais inserções possuem baixa prevalência, não foram relatadas em caráter de coexistência no Brasil e estão relacionadas com a resistência a múltiplas drogas, tornando o achado relevante do ponto de vista epidemiológico.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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P-glycoprotein is an adenosine triphosphate (ATP)-driven drug efflux carrier responsible for transport of xenobiotics and multiple classes of drugs, many usually use in veterinary medicine. Encoded by MDR1 gene, also referred to as ABCB1, located on chromosome 14, is expressed in many tissues with secretory or excretory functions, such as liver, kidney and intestine, where it limits drug absorption from the gut and promotes drug excretion into the bile and urine of their substrates. In 2001, a 4 base pair gene deletion mutation in the canine MDR1 gene was identified as MDR1-1▲, ABCB1-1▲, MDR1 MDR1 nt 230 (del4) and associated with an non-functional Pglycoprotein. The clinical correlation is the (hyper) sensitivity of certain dogs breeds, mostly collies, to a few classes of drugs such as anticancer drugs (doxorubicin, vincristine, vinblastine), immunosuppressants (cyclosporine), antiparasitic drugs (ivermectin, moxidectin), steroids hormones (aldosterone, cortisol, dexamethasone), antimicrobial agents (tetracycline, doxycycline, levofloxacin, ketoconazole, itraconazole), analgesics (morphine, methadone), antidiarrheals (loperamide), antiepileptic agents (phenothiazine), cardiac drugs (digoxin, diltiazem, verapamil, talinolol) and others. Dogs with homozygous MDR1 nt 230 (del4) MDR1 mutations (MDR1 - / -) have a higher predisposition to intoxication with substrates of P-gp than heterozygous (MDR1 + / -) and these are more likely than dogs homozygous nonmutant (MDR1 +/ +). After the identification of nt230 (del4) mutation, several molecular techniques have been developed for identification of mutant animals as a diagnostic method. The importance of molecular diagnosis is, after the identification of mutant animals, establish treatment protocols safe, exclude this animals from reproduction (genetic selection program) and investigating the history of adverse drugs reactions... (Complete abstract click electronic access below)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Germline mutations in TP53 gene are associated with Li-Fraumeni syndrome (LFS) and its variants Li-Fraumeni-like (LFL). They predispose carriers to a wide variety of early onset tumors. In Brazil, there is a high frequency of a germline mutation in this gene (NC_000017.9: c.1010G>A; p.R337H) in Southern and Southeastern regions, due to a founder effect. It is estimated to be present in 0,3% ofthe local population, but only few families have been detected. Due to this significant divergence, the purpose of this study was to verify the effectiveness of wider criteria for detection of these individuals. Herein, clinical criteria were established, DNA samples were collected, analyzed by Restriction Fragment Length Polymorphism (RFLP) and sequenced. Thus, assessing the prevalence of this mutation in families with multiple cases of cancer. Based on our proposed criteria, one out of 31 patients (3,22%) was found to carry p.R337H mutation. The patient developed ductal invasive breast cancer at age 47, invasive adenocarcinoma of the lung at age 48 and soft-tissue sarcoma at age 49. In addition, an extensive cancer family history was referred, atypical for LFS, including a case of Ewing’s sarcoma. These outcomes indicate that the proposed criteria may detect probable carriers who did not fit previous LFS criteria. Nevertheless, additional studies, which might include a larger number of families and more stringent parameters, will be useful to improve screening sensibility
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Assessing Pathogenicity for Novel Mutation/Sequence Variants: The Value of Healthy Older Individuals
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Improvement in DNA technology is increasingly revealing unexpected/unknown mutations in healthy persons and generating anxiety due to their still unknown health consequences. We report a 44-year-old healthy father of a 10-year-old daughter with bilateral coloboma and hearing loss, but without muscle weakness, in whom a whole-genome CGH revealed a deletion of exons 38-44 in the dystrophin gene. This mutation was inherited from her asymptomatic father, who was further clinically and molecularly evaluated for prognosis and genetic counseling (GC). This deletion was never identified by us in 982 Duchenne/Becker patients. To assess whether the present case represents a rare case of non-penetrance, and aiming to obtain more information for prognosis and GC, we suggested that healthy older relatives submit their DNA for analysis, to which several complied. Mutation analysis revealed that his mother, brother, and 56-year-old maternal uncle also carry the 38-44 deletion, suggesting it an unlikely cause of muscle weakness. Genome sequencing will disclose mutations and variants whose health impact are still unknown, raising important problems in interpreting results, defining prognosis, and discussing GC. We suggest that, in addition to family history, keeping the DNA of older relatives could be very informative, in particular for those interested in having their genome sequenced.
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Despite the beneficial effects of imatinib mesylate, some patients may either not respond or respond suboptimally. Here, we report two chronic myelogenous leukemia patients; one had a suboptimal response according to European LeukemiaNet criteria (a major molecular response was not achieved after 18 months of standard-dose imatinib therapy) and the other had failure with a standard dose of imatinib. At the time of the suboptimal response in patient 1 and the failure in patient 2, we were able to detect the F359I mutation in the BCR-ABL tyrosine kinase domain using DNA sequencing in both patients. Therefore, it was decided to change the therapeutic regimen to dasatinib at a dose of 100 mg once daily in both patients. This change resulted in the achievement of complete cytogenetic remission in patient 1 after 4 months and a major molecular response within 2 and 3 months in both patients. Detection of the F359I mutation in our two cases likely explains the suboptimal response to imatinib in case 1 and the failure in case 2. This implies that in such cases dasatinib should be considered to effectively suppress the mutated clones. Copyright (C) 2011 S. Karger AG, Basel
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We ascertained a Brazilian family with nine individuals affected by autosomal dominant nonsyndromic sensorineural hearing loss. The bilateral hearing loss affected mainly mid-high frequencies, was apparently stable with an early onset. Microsatellites close to the DFNA8/DFNA12 locus, which harbors the TECTA gene, showed significant multipoint lod scores (32) close to marker D11S4107. Sequencing of the exons and exon-intron boundaries of the TECTA gene in one affected subject revealed the deletion c.5383 + 5delGTGA in the 5' end of intron 16, that includes the last two bases of the donor splice site consensus sequence. This mutation segregates with deafness within the family. To date, 33 different TECTA mutations associated with autossomal dominant hearing loss have been described. Among them is the mutation reported herein, first described by Hildebrand et al. (2011) in a UK family. The audioprofiles from the UK and Brazilian families were similar. In order to investigate the transcripts produced by the mutated allele, we performed cDNA analysis of a lymphoblastoid cell line from an affected heterozygote with the c.5383 + 5delGTGA and a noncarrier from the same family. The analysis allowed us to identify an aberrant transcript with skipping of exon 16, without affecting the reading frame. One of the dominant TECTA mutations already described, a synonymous substitution in exon 16 (c.5331 G<A), was also shown to affect splicing resulting in an aberrant transcript lacking exon 16. Despite the difference in the DNA level, both the synonymous substitution in exon 16 (c.5331 G<A) and the mutation described herein affect splicing of exon 16, leading to its skipping. At the protein level they would have the same effect, an in-frame deletion of 37 amino-acids (p.S1758Y/G1759_N1795del) probably leading to an impaired function of the ZP domain. Thus, like the TECTA missense mutations associated with dominant hearing loss, the c5383 + 5delGTGA mutation does not have an inactivating effect on the protein. (C) 2012 Elsevier B.V. All rights reserved.