HEREDITARY PREDISPOSITIONS TO CANCER - TH E GENETIC DIAGNOSIS IN PRACTICE

Genetic consultations allow to identify families in which an hereditar y predisposition to cancer is transmitted. in most cases the gene invo lved can be studied leading to identification of families members carr ying or not the mutation conferring the cancer risk. In this case, can cer risk is more accurately explained and measures, adjusted to the ri sk were proposed for early screening of the disease Capacities to cara cterize an inherited mutation of the susceptibility gene vary accordin g to our knowledge of the gene, its structure, its function, the kind of mutation(s) and also, the available techniques. The purpose of this paper is to describe the most frequently used techniques for direct o r indirect molecular diagnosis of cancer predisposition and to specify , for each of them, the situations where its use seem the fittest. The example of breast cancer hereditary predisposition, where multiple su sceptibility genes were identified and other are still unknown, illust rates the various degree of diagnosis that can be proposed and the str ategy techniques used according to the gene.