Determination of a BRCA1 gene mutation in a family with hereditary breast cancer

Abstract

Background: Breast cancer is the main cause of death among fore, the women between 40 and 55 years old, in whom the hereditary cases are common. Therefore molecular diagnosis of germ line initiations involved in breast cancer susceptibilily is relevant. BRCA1 and BRCA2 have been described as the two major genes involved in familial breast/ovarian cancer. We are performing a screening for BRCA 1 and BRCA2 genes, in a group of 50 high risk Chilean families for breast/ovarian cancer. We have detected a mutation, 3936 C > T, that leads to a truncated protein, in two affected women from one of the families in study.

Aim: To report the results of the screening for 3936 C > T healthy relatives of index women.

Material and methods: The molecular diagnosis of this mutation was offered to the healthy inemembers of this family, and 17 relatives accepted to be tested. The region of the BRCA 1 gene that includes the 3936 C > T mutation, was analyzed through PCR amplification, digestion with restriction enzyme BstNI, and direct sequencing.

Results: 3936 C > T DNA mutation was present in 8 relatives.

Conclusions: Considering the high risk, of having a mutation in the BRCA 1 gene, specially in pre-menopausal women, the molecualr diagnosis, genetic and clinical counseling are highly relevant. In Chile the molecualr diagnosis is still not widely applied.