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BRCA1 Gene (brca1 + gene)
Selected AbstractsA Frailty-Model-Based Approach to Estimating the Age-Dependent Penetrance Function of Candidate Genes Using Population-Based Case-Control Study Designs: An Application to Data on the BRCA1 GeneBIOMETRICS, Issue 4 2009Lu Chen Summary The population-based case,control study design is perhaps one of, if not the most, commonly used designs for investigating the genetic and environmental contributions to disease risk in epidemiological studies. Ages at onset and disease status of family members are routinely and systematically collected from the participants in this design. Considering age at onset in relatives as an outcome, this article is focused on using the family history information to obtain the hazard function, i.e., age-dependent penetrance function, of candidate genes from case,control studies. A frailty-model-based approach is proposed to accommodate the shared risk among family members that is not accounted for by observed risk factors. This approach is further extended to accommodate missing genotypes in family members and a two-phase case,control sampling design. Simulation results show that the proposed method performs well in realistic settings. Finally, a population-based two-phase case,control breast cancer study of the BRCA1 gene is used to illustrate the method. [source] Prevalence of BRCA1 genomic rearrangements in a large cohort of Italian breast and breast/ovarian cancer families without detectable BRCA1 and BRCA2 point mutationsGENES, CHROMOSOMES AND CANCER, Issue 9 2006Simona Agata The presence of genomic rearrangements of the BRCA1 gene in breast and/or ovarian cancer families has been intensively investigated in patients from various countries over the last years. A number of different rearrangements have been reported by several studies that clearly document the involvement of this mutation type in genetic predisposition to breast and ovarian cancer. Population-specific studies are now needed to evaluate the prevalence of genomic rearrangements before deciding whether to include ad hoc screening procedures into standard diagnostic mutation detection approaches. Indeed, the vast majority of the studies have been performed on small, highly selected, sample sets because of the limitations imposed by the laborious technical approaches. Moreover, prevalence figures are likely to differ across different countries according to the ethnic origin of each specific population. Here we analyze a large cohort of 653 Italian probands, negative for BRCA1 and BRCA2 point mutations, gathered from four National Institutions. We report the identification of BRCA1 genomic rearrangements in 12 independent families. Noteworthy, half of the probands carry mutations that recur in more than one Italian family. Considering the whole spectrum of Italian BRCA1 gene rearrangements identified thus far in consecutive patients, we estimate that alterations of this type account for 19% (95% CI: 0.11 < 0.19 < 0.28) of the BRCA1 mutation positive families. We conclude that the search for major genomic rearrangements is essential for an accurate and comprehensive BRCA1 mutation detection strategy in Italy. © 2006 Wiley-Liss, Inc. [source] Novel germline BRCA1 and BRCA2 mutations in breast and breast/ovarian cancer families from the Czech Republic ,,HUMAN MUTATION, Issue 6 2001Eva Machackova Abstract Germline mutations in breast cancer susceptibility genes, BRCA1 and BRCA2, are responsible for a substantial proportion of high-risk breast and breast/ovarian cancer families. To characterize the spectrum of BRCA1 and BRCA2 mutations, we screened Czech families with breast/ovarian cancer using the non-radioactive protein truncation test, heteroduplex analysis and direct sequencing. In a group of 100 high-risk breast and breast/ovarian cancer families, four novel frame shift mutations were identified in BRCA1 and BRCA2 genes. In BRCA1, two novel frame shift mutations were identified as 3761-3762delGA and 2616-2617ins10; in BRCA2, two novel frame shift mutations were identified as 5073-5074delCT and 6866delC. Furthermore, a novel missense substitution M18K in BRCA1 gene in a breast/ovarian cancer family was identified which lies adjacent just upstream of the most highly conserved C3HC4 RING zinc finger motif. To examine the tertiary structure of the RING zinc finger domain and possible effects of M18K substitution on its stability, we used threading techniques according to the crystal structure of RAG1 dimerization domain of the DNA-binding protein. © 2000 Wiley-Liss, Inc. [source] Evidence of a founder mutation of BRCA1 in a highly homogeneous population from southern Italy with breast/ovarian cancerHUMAN MUTATION, Issue 2 2001Francesco Baudi Abstract 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. Hum Mutat 18:163,164, 2001. © 2001 Wiley-Liss, Inc. [source] Germline mutations 657del5 of the NBS1 gene contribute significantly to the incidence of breast cancer in Central PolandINTERNATIONAL JOURNAL OF CANCER, Issue 2 2006Jan Steffen Abstract Recent studies have demonstrated that heterozygous carriers of the NBS1 657del5 mutation have an increased risk for familial and bilateral breast cancer, but similar studies in consecutive breast cancer patients were inconclusive. Here, in a study of 562 nonselected breast cancer patients from Central Poland, we found 11 (1.96%) 657del5 mutation carriers vs. 3.47 expected (OR 3.21, 95%CI: 1.36,7.61, p = 0.0107) and only 9 (1.6%) carriers of the 5382insC mutation of the BRCA1 gene, most frequently found among breast cancer patients in Poland. No carriers of R215W, another pathogenic mutation of the NBS1 gene, were found in the present study. All carriers of the 657del5 mutation had sporadic breast tumors while 5 of 9 5382insC carriers had a family history of breast/ovarian cancer or bilateral breast carcinoma. In the pooled group of patients from the present and our previous study, carried out also in patients from Central Poland, we obtained the following risk estimates (OR) for 657del5 carriers, as related to the age at breast cancer diagnosis: <40 years: 8.36; (95%CI: 2.57,27.27) p = 0.0003; <50 years: 4.27 (95%CI: 1.67,10.89) p = 0.003; ,50 years: 2.40 (95%CI: 0.91,6.35) p = 0.1250; all ages: 3.13 (95% CI: 1.40,7.00) p = 0.0066. These findings demonstrate conclusively that NBS1 657del5 mutation carriers have a significantly, though moderately increased, age-related risk of breast cancer, and imply that in populations with a high 657del5 carrier frequency this mutation may contribute substantially to the overall incidence of breast cancer, particularly in younger age groups. © 2006 Wiley-Liss, Inc. [source] A single nucleotide (T,G) polymorphism within intron 23 of the canine BRCA1 geneANIMAL GENETICS, Issue 1 2000I S Gray First page of article [source] The Impact of BRCA1 on Spina Bifida Meningomyelocele LesionsANNALS OF HUMAN GENETICS, Issue 6 2007Terri M. King Summary We examined the BRCA1 gene in 268 patients, and their parents, with a specific diagnosis of spina bifida meningomyelocele (SBMM). We genotyped two intragenic microsatellite markers (BRCA1 D17S1323, BRCA1 D17S1322) and 2 single nucleotide polymorphisms (A1186G, A4956G) in our patients. Transmission disequilibrium testing (TDT) showed significant association with A4956G, but not with A1186G. Extended TDT demonstrated over-transmission of the 17GT allele in BRCA1 D17S1323 and the 14GTT allele in BRCA1 D17S1322, and under-transmission of the 20GT allele in BRCA1 D17S1323 and the 16GTT allele in BRCA1 D17S1322. Our data included location of the rostral edge of the lesion. Individuals homozygous for the 17GT allele for BRCA1 D17S1323 were more likely to have SB lesions located caudally, while heterozygotes with the 17GT allele for BRCA1 D17S1323 had a more rostral lesion. Individuals heterozygous for the 16GTT allele of BRCA1 D17S1322 were more likely to have rostral lesions. We measured gene expression in CEPH members and demonstrated differential expression levels of BRCA1 associated with these polymorphisms. Integrating our data with HapMap findings showed that the polymorphic markers are associated with distinct haplotypes. We conclude that the BRCA1 gene is associated with SBMM and participates in the phenotypic variability seen in SBMM. [source] Analysis of BRCA1 and BRCA2 in breast and breast/ovarian cancer families shows population substructure in the Iberian peninsulaANNALS OF HUMAN GENETICS, Issue 1 2002A. VEGA An estimated 5,10% of all breast and ovarian cancers are due to an inherited predisposition, representing a rather large number of patients. In Spain 1/13,1/14 women will be diagnosed with breast cancer during their lifetime. Two major breast cancer genes, BRCA1 and BRCA2, have been identified. To date, several hundred pathogenic mutations in these two genes have been published or reported to the Breast Cancer Information Core, BIC database (http://www.nhgri.nih.gov/Intramural_research_Labtransfer/Bic/index.html). In the present study, 30 Spanish breast and breast/ovarian cancer families (29 from Galicia, NW Spain, and 1 from Catalonia, NE Spain) were screened for mutations in the BRCA1 and BRCA2 genes. The analysis of these genes was carried out by SSCP for shorter exons and direct sequencing in the case of longer ones. Mutations were found in 8 of the 30 families studied (26.66%). It is important to note that all mutations were detected within the BRCA1 gene: 330 A>G, 910_913delGTTC, 2121 C>T, 3958_3962delCTCAGinsAGGC, and 5530 T>A. The BRCA1 330 A>G mutation was found in four unrelated families and accounted for 50% of all identified mutations. [source] A Frailty-Model-Based Approach to Estimating the Age-Dependent Penetrance Function of Candidate Genes Using Population-Based Case-Control Study Designs: An Application to Data on the BRCA1 GeneBIOMETRICS, Issue 4 2009Lu Chen Summary The population-based case,control study design is perhaps one of, if not the most, commonly used designs for investigating the genetic and environmental contributions to disease risk in epidemiological studies. Ages at onset and disease status of family members are routinely and systematically collected from the participants in this design. Considering age at onset in relatives as an outcome, this article is focused on using the family history information to obtain the hazard function, i.e., age-dependent penetrance function, of candidate genes from case,control studies. A frailty-model-based approach is proposed to accommodate the shared risk among family members that is not accounted for by observed risk factors. This approach is further extended to accommodate missing genotypes in family members and a two-phase case,control sampling design. Simulation results show that the proposed method performs well in realistic settings. Finally, a population-based two-phase case,control breast cancer study of the BRCA1 gene is used to illustrate the method. [source] | |||||||||||||