[Genetic counseling for adults: the risk of late-onset inherited diseases].

Genetic counselling for adults is not classical since it deals with prospective assessment of risk in developing disease. 1% of adults have a monogenic disease, or are carriers of a genotype predisposing to a disease. Situations that need genetic counselling are: confirmation of a diagnosis of an inherited disease already known in the family; discovery of a new genetic disease in an adult with no family history of the disease (reduced penetrance); and presymptomatic and prenatal diagnosis for late onset diseases. The prescription of presymptomatic testing is limited to the intervention of multidisciplinary teams, bringing together medical expertise and notified to needed. This is a special situation because it is not always followed by a preventive action or treatment.