Haplotype analysis in German families with recurrent BRCA1 and BRCA2 mutations
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KeywordsBRCA Mutation Frequent Mutation Haplotype Analysis BRCA1 Gene Common Haplotype
Association analysis was performed for 19 different BRCA mutations (BRCA1: 14; BRCA2: 5), which were detected at least three times in the German population. The aim of this study is the identification of founder mutations and hot-spot mutations that are specific for the German population. Patients were genotyped for three intragenic markers (D17S855, D17S1322 and D17S1323) in the BRCA1 gene and for closely flanking markers (D13S1698, D13S171 and D13S267) in the BRCA2 gene. Statistical analysis was performed with an exact test of goodness-of-fit (Müller et al: 1991). The genotype data for the three markers analyzed each in the BRCA1 and BRCA2 genes are in concordance with the presence of probable common haplotypes. Therefore, most of the frequent mutations detected are likely to be founder mutations. Suprisingly, four C → T transitions in the BRCA1 gene, which had been expected to result from independent mutational events, are probably also founder mutations. In contrast, the 4-bp deletion in the BRCA1 gene (4184del4bp) and the most frequent mutation 3034delA in BRCA2 are recurrent mutations, for which no significant association with specific founder alleles could be shown. Testing further informative family members to define the specific haplotype is the aim of our current investigations.