BRCA1 5272-1G>A and BRCA2 5374delTATG are founder mutations of high relevance for genetic counselling in breast/ovarian cancer families of Spanish origin

Infante M, Durán M, Acedo A, Pérez-Cabornero L, Sanz DJ, García-González M, Beristain E, Esteban-Cardeñosa E, de la Hoya M, Teulé A, Vega A, Tejada M-I, Lastra E, Miner C, Velasco EA. BRCA1 5272-1G>A and BRCA2 5374delTATG are founder mutations of high relevance for genetic counselling in breast/ovarian cancer families of Spanish origin.
The distribution of BRCA1 and BRCA2 germ line mutations in breast/ovarian cancer families varies among different populations, which typically present a wide spectrum of unique mutations. Splicing mutation 5272-1G>A of BRCA1 and frameshift mutation 5374delTATG of BRCA2 are highly prevalent mutations in Castilla-León (Spain), accounting for 18.4% and 13.6% of BRCA1 and BRCA2 positive families, respectively. To test the presence of founder effects, 9 Spanish 5272-1G>A and 13 5374delTATG families were genotyped with polymorphic markers linked to BRCA1 or BRCA2 . All the 5272-1G>A families shared a common haplotype in eight markers (1.1 Mb region) and the mutation age was estimated in 15 generations (∼380 years). A conserved haplotype associated to 5374delTATG was observed in four markers (0.82 Mb). The mutation occurred approximately 48 generations ago (∼1200 years). Each mutation likely arose from a common ancestor that could be traced to a small area of Castilla-León and expanded to other Spanish regions. They can have a significant impact on the clinical management of asymptomatic carriers as well as on the genetic screening strategy to be followed in populations with Spanish ancestries.