[Hereditary predisposition to breast cancer (1): genetics].

The main objective of oncogenetics is to characterize a subpopulation of patients at high risk of cancer development at an early age in order to provide specific recommendations for an optimized follow-up and care path. Oncogenetic counselling helps to assess individual risk from a family history. By a family approach of formal genetics, the key issue is to identify families with a strong aggregation of cancers, and, in particular, suggesting a specific syndrome of inherited predisposition to cancer. This approach can lead to the proposal of germline genetic testing in search of causal mutations. As up to know, the search for a constitutional mutation in the BRCA genes has led to the identification of a causal deleterious mutation in less than 10% of index-cases analyzed. It is therefore important to evaluate the impact of new genes in the current panorama of inherited predisposition to breast and ovarian cancer.