An international study led by teams from France, Slovakia, and Spain has analysed the prion strains present in 24 patients with genetic Creutzfeldt–Jakob disease (gCJD) who carry the E200K mutation, the most common variant of the PRNP gene associated with this disease. Using transgenic mouse models with human prion protein, the researchers identified that the strains detected correspond to the two most common strains in sporadic CJD (M1CJD and V2CJD), present individually or in combination. The study also confirmed the presence of prion infectivity in peripheral tissues, with a distribution pattern similar to that observed in sporadic cases. These findings reinforce the idea that carriers of the E200K mutation can serve as a valuable model for studying the preclinical stages of the disease.