[Genetics of human subacute spongiform encephalopathies].

Variations in PRNP, the gene that encodes PrP in humans, play a major role in the genetic predisposition to prion diseases. Mutations in PRNP are found in patients with familial forms and are considered as causative. A coding polymorphism in PRNP (129 Met/Val) defines a predisposing factor to sporadic and acquired forms. Other favouring genes have been searched without real success. Both animal models and cellular models have been constructed to study the molecular mechanisms implied in the disease genesis.