BRCA1 and BRCA2 mutations in Belgian families with a history of breast and/or ovarian cancer.

Certain familial breast and/or ovarian cancers, specially those diagnosed early, are dominantly heritable and have been linked to mutations in BRCA1 and BRCA2 genes. We have tested 30 women selected from 25 different families with specific criteria. Blood samples were always taken with the informed consent and preliminary interview of the patient by a physicologist specialized in presymptomatic testing. Mutation detection were performed by protein truncation test (PTT), gradient gel electrophoresis (DGGE) and subsequent sequencing. The results showed four frameshift mutations among which three induced truncation of the BRCA1 protein and one of the BRCA2 protein. One of the BRCA1 mutations and the only BRCA2 mutation are prevelant among caucasians. Interestingly, one BRCA1 mutation is shared both by Dutch and French families and another one has not yet been reported. Furthermore, a new unclassified variant was identified.,by using specific selection criteria, we have been able to detect BRCA mutations in four out of the 25 families tested. One of the mutations seems to be found only in Belgium. Genetic counselling is being offered to their relatives.