Prion diseases are rare neurologic affections with a poor prognosis, occurring in both humans and animals. Creutzfeldt-Jakob disease (CJD) secondary to human extracted growth hormone treatment is the most frequent condition in pediatrics. In 1994, a new type of CJD (variant CJD) was described in young adults in the United Kingdom, only 10 years after the bovine spongiform encephalopathy epidemic, with recent works showing a direct relationship between the bovine epidemic and the human cases. An accumulation of a single protein called the prion protein (PrP) has been discovered in the brain in all of these cases, animal and human, leading to the hypothesis that a new infectious agent could proceed without any nuclear acid information; another hypothesis is that of a still unknown viral agent. The PRNP gene encoding for this PrP protein is well described: some mutations and a polymorphism in the 129th codon have been shown to be implicated in many cases of CJD. PrP is a ubiquitous protein, with yet unknown physiological function. There are still many questions to be answered: shall we expect new pediatric cases of variant CJD? Assuming that animal-human contamination is related to alimentation, are there other ways of contamination.