Uncertainty exists whether the 4154delA mutation of the BRCA1 gene detected in unrelated individuals from Latvia, Poland and Russia is a founder mutation with a common ancestral origin. To trace back this problem we analysed the mutation-associated haplotype of the BRCA1 intragenic SNPs as well as intragenic and nearby STR markers in mutation carriers from the aforementioned populations. The mutation-associated SNP alleles were found to be "T-A-A-A-A-G" for six intragenic SNPs of the BRCA1 gene (IVS8-58delT, 3232A/G, 3667A/G, IVS16-68A/G, IVS16-92A/G, IVS18+66G/A, respectively). The alleles 195, 154, 210 and 181 were found to be associated with the 4154delA mutation for STR markers D17S1325, D17S855, D17S1328 and D17S1320, correspondingly. Further analysis of markers in the 4154delA mutation carriers from all three populations allows us to assert that all analysed mutation carriers share a common ancestry.
Department of Molecular and Regenerative Medicine, Hematology, Oncology and Transfusion Medicine Center, Vilnius University Hospital Santariškiu Clinics, Santariškiu st. 2, Vilnius LT-08661, Lithuania. email@example.com
Uncertainty exists about the origin of BRCA1 c.4035delA mutation which is prevalent in Baltic countries, with the highest frequency being in Lithuania (53% of all BRCA1 mutations), although formal founder mutation analysis by haplotype has not yet been undertaken. In this study we genotyped 78 unrelated BRCA1 c.4035delA mutation carriers families from Lithuania, Latvia, Poland and Russia. The results from the haplotype analyses were used to estimate the age of the mutation. Using maximum likelihood methods we estimated that the mutation arose approximately 1550 years (62 generations of 25 years) ago (ca. 5th century) somewhere in the present territory of Lithuania, in the area inhabited by ancient Baltic tribes at that time. Our results show that this mutation gradually entered the gene pool in the neighboring countries.