RESUMO
Several genes have been involved in the pathogenesis of hereditary breast/ovarian cancer (BOC), but mutations in the BRCA1 gene are by far the most recurrent. In this study, we report the identification of a founder mutation in a geographically and historically homogeneous population from Calabria, a south Italian region. A screening performed on 24 patients from unrelated families highlighted the high prevalence of a 5083del19 alteration in the BRCA1 gene, which accounts for 33% of the overall gene mutations. The same mutation was also detected in 4 patients, all of Calabrian origin, referred to us by research centres from the north of Italy. Allelotype analysis, performed on probands and unaffected family members revealed the presence a common allele, therefore suggesting a founder effect due to a common ancestor. Our findings underscore the importance of ethnic background homogeneity in patients' selection and highlight the usefulness of founder mutations as a potential tool for optimisation of preclinical diagnosis in gene carriers and therapeutic approaches in affected individuals.
Assuntos
Neoplasias da Mama/genética , Efeito Fundador , Genes BRCA1 , Mutação/genética , Neoplasias Ovarianas/genética , Adulto , Alelos , Análise Mutacional de DNA , Etnicidade/genética , Éxons/genética , Feminino , Haplótipos/genética , Humanos , Íntrons/genética , Itália/etnologia , Repetições de Microssatélites/genética , Pessoa de Meia-Idade , Polimorfismo Conformacional de Fita SimplesRESUMO
We have characterized the promoter region of the human gene coding for the MLH1 mismatch repair protein. The total transcriptional activity of the hMLH1 promoter is driven by two positive cis-elements included between nucleotides -300 and -220. The upstream element is a canonical CCAAT box, and it is recognized by the heterotrimeric transcription factor NF-Y. On the other hand, the downstream element is recognized by a nuclear factor of about 120 kDa. Variations in hMLH1 intracellular levels may influence the surveillance of the genome integrity. The identification of the two elements may shad some light on the regulation of the transcriptional regulation of hMLH1 expression.
Assuntos
Proteínas de Neoplasias/genética , Regiões Promotoras Genéticas/genética , Proteínas Adaptadoras de Transdução de Sinal , Proteínas de Transporte , Cloranfenicol O-Acetiltransferase/genética , Cloranfenicol O-Acetiltransferase/metabolismo , DNA/genética , DNA/metabolismo , Reparo do DNA , Ensaio de Desvio de Mobilidade Eletroforética , Regulação da Expressão Gênica , Células HeLa , Humanos , Proteína 1 Homóloga a MutL , Proteínas Nucleares/metabolismo , Ligação Proteica , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Deleção de Sequência , Fatores de Transcrição/metabolismo , Transcrição Gênica , Transfecção , beta-Galactosidase/genética , beta-Galactosidase/metabolismoAssuntos
Sistemas de Notificação de Reações Adversas a Medicamentos/organização & administração , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Legislação de Medicamentos , United States Food and Drug Administration , Sistemas de Notificação de Reações Adversas a Medicamentos/legislação & jurisprudência , Comunicação , Humanos , Medição de Risco , Estados UnidosRESUMO
Huntington disease (HD) is a neurodegenerative disorder caused by an expanded trinucleotide repeat (CAG)n located at the 5' end of the novel IT15 gene. Discovery of this expansion allows the molecular diagnosis of HD by measuring repeat length. We applied a simple nonisotopic method to detect (CAG)n repeats, avoiding both radioactive and Southern transfer analysis. The assay is based on direct visualization of electrophoresed PCR products, after silver nitrate gel staining. Its accurate sizing of HD alleles allows presymptomatic diagnosis of at-risk persons. By avoiding isotopic manipulations, the method is safe and accurate, with no radioactive background bands. Furthermore, because it permits direct allele visualization after gel staining, the method is simple and rapid, allowing allele sizing within hours rather than days.
Assuntos
Doença de Huntington/genética , Mutação , Reação em Cadeia da Polimerase/métodos , Proteínas/genética , Sequências Repetitivas de Ácido Nucleico , Alelos , Primers do DNA , Humanos , Proteína Huntingtina , Doença de Huntington/diagnóstico , Proteínas do Tecido Nervoso , Proteínas Nucleares , Nitrato de Prata , Coloração e RotulagemRESUMO
Spinocerebellar ataxia type 1 is caused by the expansion of a CAG trinucleotide repeat, located at the 5' end of the gene responsible for the disease (SCA1 gene). We propose a simple and rapid method for SCA1 diagnosis, avoiding both radioactive and Southern blotting analysis. The method allows an accurate allele sizing by visualization of polymerase chain reaction products through a silver nitrate-stained polyacrylamide gel.
Assuntos
Degenerações Espinocerebelares/genética , Repetições de Trinucleotídeos/genética , Enzimas de Restrição do DNA , Eletroforese em Gel de Ágar , Marcadores Genéticos , HumanosRESUMO
Hereditary nonpolyposis colon cancer results from heritable defects in the MLH1, MSH2, PMS1 and PMS2 genes, which encode proteins involved in the mismatch repair process. In this work we report the identification of two novel germline mutations in the MLH1 gene from two unrelated HNPCC families. The two affected families do not fulfill the Amsterdam criteria. In family 1 we found a missense S93G mutation, which lies in a MLH1 domain critical for its MMR functions. In family 2 we found a two nucleotide insertion (AG) in position 523 from the AUG which determines an early stop codon at position 606 (codon 203). In both families the mutant alleles cosegregate with the cancer phenotype.