The role of chronogenetics and of gemellology in the prevention of genetic morbidity.

The prevention of hereditary diseases after birth is essentially based on the detection of these diseases at their preclinical level. This may be made possible through a careful pedigree examination and possible identification of a "genealogical alarm", as well as a detailed clinical examination of the subject and possible identification of preclinical signs of the pathogenesis, i.e., of a "clinical alarm". The respective roles of chronogenetics and of gemellology in this approach are reviewed.